Term
| What is the function of the digestive system? |
|
Definition
| Supply nutrients from the environment to the circulatory system |
|
|
Term
| The digestive system is a long tube resembling a _____. |
|
Definition
|
|
Term
| The digestive sys converts ____ into ____. |
|
Definition
| Macromolecules; Micromolecules |
|
|
Term
| Give some examples of macromolecules. |
|
Definition
| Proteins, Fats, Carbohydrates |
|
|
Term
| Give some examples of micromolecules. |
|
Definition
| Amino acids, Fatty acids, Monosaccharides |
|
|
Term
| Macromolecules are converted to micromolecules by _____ means, assisted by _____. |
|
Definition
| Mechanical & Chemical; Accessory Organs |
|
|
Term
| What are the 3 fundamental processes of the digestive sys? |
|
Definition
| Motility, Secretions, Absorption |
|
|
Term
| Motility; = _____ digestion |
|
Definition
| Smooth m. contractions to crush, mix, & propel contents = mechanical digestion |
|
|
Term
| Secretions; = ____ digestion |
|
Definition
| Delivery of digestive enzymes, mucus, ions & fluid to create an aqueous phase = chemical digestion |
|
|
Term
|
Definition
| Transport of nutrients, water, ions across the epithelium |
|
|
Term
| Digestion requires tight ____ systems involving ____ & ____ messages. |
|
Definition
| Control; Hormonal & Neural |
|
|
Term
| What are the 2 main functions of control systems in the digestive sys? |
|
Definition
| Adjust GI activity to quality/quantity of incoming food; Facilitate communication btw GI sections a/o CNS |
|
|
Term
| What type of molecules are absorbed in the GI tract? |
|
Definition
|
|
Term
| What are the basic parts of the GI tract? |
|
Definition
| Mouth, Esophagus, Stomach, Liver/Bile, Pancreas, SI, LI, (Forestomach/Rumen) |
|
|
Term
| What is the function of the mouth? |
|
Definition
| Mechanical breakdown of food, Addition of saliva as a lubricant |
|
|
Term
| What is the function of the esophagus? |
|
Definition
| Conduit mouth/stomach (Conveyer belt) |
|
|
Term
| What is the function of the stomach? |
|
Definition
| Chemical digestion of proteins, liquefaction of food (Food grinder) |
|
|
Term
| What is the first "centerpiece" of digestion? |
|
Definition
|
|
Term
| What is the function of the liver? |
|
Definition
| Provision of bile salts for digestion/absorption of fats |
|
|
Term
| What is the function of the pancreas? |
|
Definition
| Provision of major digestive enzymes |
|
|
Term
| What is the function of the SI? |
|
Definition
| Provision of enzymes, Chemical digestion & absorption of nutrients & water |
|
|
Term
| By what point in the GI tract should chemical digestion & absorption of nutrients be completed? |
|
Definition
|
|
Term
| What is the function of the LI? |
|
Definition
| Absorption of water, feces formation, bacterial fermentation (major species differences) |
|
|
Term
| What is the function of the forestomach/rumen? |
|
Definition
| Bacterial fermentation of nutrients & absorption of fermentation products |
|
|
Term
| Most ingested nutrients are in the form of _____. |
|
Definition
|
|
Term
| Macromolecules need to be ____ by ____ into simple molecules before they can be ____. |
|
Definition
| Hydrolyzed; Enzymes; Absorbed |
|
|
Term
| What is the structure of a protein? |
|
Definition
| Amino Acids (amino & carboxyl group) linked by peptide bonds |
|
|
Term
| What is the structure of a triglyceride? |
|
Definition
| 3 fatty acids w/ a glycerol backbone |
|
|
Term
| What is the structure of glucose? |
|
Definition
| 6 C ring linked @ C1 & C4 (alpha linkage) |
|
|
Term
|
Definition
| Splitting a bondage by add'n of H2O |
|
|
Term
| What is the prefix for a peptide >25? |
|
Definition
|
|
Term
| What is the prefix for a peptide <25? |
|
Definition
|
|
Term
| Most fatty acids have a ____ # of Cs. |
|
Definition
|
|
Term
| The digestive tract is mostly a long, _____ tube, geared towards ______. |
|
Definition
| Smooth m., Coordinated Motility |
|
|
Term
| The GI tract is a single-unit type ____. |
|
Definition
|
|
Term
| GI smooth mm. are ______ cells w/ _____ resting membrane potentials. |
|
Definition
| Self-Excitatory; Undulating |
|
|
Term
| The smooth m. cells of the GI tract exhibit ____ & ____. |
|
Definition
| Slow Waves; Spike Potentials |
|
|
Term
| What is resting membrane potential? |
|
Definition
|
|
Term
| Where is the midline of the GI cell undulations? |
|
Definition
|
|
Term
| What generates the resting membrane potential in the GI tract? |
|
Definition
| Specialized smooth m. cells (Cajal) |
|
|
Term
| b/o ____, slow waves are conducted along a GI section. |
|
Definition
|
|
Term
| Slow waves occur w/ a frequency of ____, d/o the gut section. |
|
Definition
|
|
Term
| Are slow waves contractions? |
|
Definition
|
|
Term
| Only when a slow wave peak reaches _____, contractions occur. |
|
Definition
| Critical Threshold Potential (-40/-35mV) |
|
|
Term
| What happens when slow wave peaks reach threshold? |
|
Definition
| Voltage-gated Ca ch's open --> Rapid influx of Ca causes spike potentials & elicits m. contractions, which spread along GI section |
|
|
Term
| # of contractions is determined by _______. |
|
Definition
| # of peaks/waves reaching threshold |
|
|
Term
| What can the amplitude of slow waves be modulated by? |
|
Definition
| Priming Factors & Hyperpolarizing Factors |
|
|
Term
| What do priming factors do? |
|
Definition
| Depolarize smooth m. membrane |
|
|
Term
| With priming factors, GI motility _______. |
|
Definition
|
|
Term
| With hyperpolarizing factors, GI motility _____. |
|
Definition
|
|
Term
| Examples of priming factors: |
|
Definition
| Gut wall stretching, Parasympathetic stimulation, some GI hormones |
|
|
Term
| Examples of hyperpolarizing factors: |
|
Definition
| Sympathetic stimulation, some GI hormones |
|
|
Term
| What are the 2 basic patterns of GI motility? |
|
Definition
| Segmentation/Mixing; Peristalsis/Propulsion |
|
|
Term
|
Definition
| Localized contraction of mostly circular mm. |
|
|
Term
| Segmentation/Mixing travels over ___ distances & has a _____ effect on gut content. |
|
Definition
|
|
Term
|
Definition
| Circular contraction Cr to a bolus w/ relaxation Cd to the bolus |
|
|
Term
| In Peristalsis/Propulsion, contraction travels ____ over ___ distances; bolus moves _____. |
|
Definition
| Analwards; Longer; Aborally |
|
|
Term
| Bolus moves aborally = strong local reflex called ____. |
|
Definition
|
|
Term
| The secretory & motor functions of the GI tract are tightly controlled by ____, ____, & ____. |
|
Definition
| Endocrine System, Nervous System (Enteric & Autonomic), & Immune System |
|
|
Term
| Which system controls digestive functions by secreting endocrines & paracrines? |
|
Definition
|
|
Term
| The enteric endocrine system controls digestive functions by secreting ____ & ____. |
|
Definition
|
|
Term
| Regulatory peptides that act via blood stream = |
|
Definition
|
|
Term
| Regulatory peptides that act via Diffusion = |
|
Definition
|
|
Term
| Enteric Endocrine system can also be stimulated via ____. |
|
Definition
|
|
Term
| How many regulatory peptides of the enteric endocrine system are known to date? |
|
Definition
|
|
Term
| Name some GI endocrine regulatory peptides. |
|
Definition
| Gastrin, Somatostatin, Secretin, Cholecystokinin, Gastric Inhibitory Peptide, Motilin, Enteroglucagon, Peptide YY |
|
|
Term
| What do the regulatory peptides of the GI endocrine cells affect? |
|
Definition
| Secretions of the GI tract & accessory organs, & their motility functions |
|
|
Term
| What do duodenal endocrine cells react to? |
|
Definition
|
|
Term
| Duodenal endocrine cells react to low pH values & release ____ into circulation |
|
Definition
|
|
Term
|
Definition
| Stimulates pancreas & liver to release buffers into the gut |
|
|
Term
| What is considered the brain of the gut? What does it consist of? |
|
Definition
| Enteric (Intrinsic) NS; Myenteric & Submucosal Plexus |
|
|
Term
| What is the unique NS of the GI system? |
|
Definition
|
|
Term
| Where is the submucosal plexus located? |
|
Definition
| Between Submucosa & 1st m. layer |
|
|
Term
| Whee does the enteric NS lie? |
|
Definition
| In the gut wall extending btw esophagus & anus |
|
|
Term
| How many neurons does the Enteric NS contain? |
|
Definition
| As many as the spinal cord |
|
|
Term
| The enteric NS is ____ & regulates GI _____, _____, & ____. |
|
Definition
| Autonomic; Smooth mm., Endocrine & Secretory cells |
|
|
Term
| What does the enteric NS enable? |
|
Definition
| Communication among adjacent GI sections (=local reflexes) |
|
|
Term
| The enteric NS uses _____. |
|
Definition
|
|
Term
| What are the NT's of the enteric NS? |
|
Definition
| ACh (mostly excitatory), Norepinephrine (mostly inhibitory), Serotonin, Dopamine, CCK, ATP, Somatostatin, Bombesin, Motilin, Substance P, Vasoactive Intestinal Peptide |
|
|
Term
| The Enteric NS is a ______ consisting of _____ |
|
Definition
| Simple Reflex System; Sensory R's, Afferent Fibers, Ganglia Cells, Efferent Fibers, Effectors |
|
|
Term
| What are the effectors of the enteric NS? |
|
Definition
| Smooth m. cells, Secretory cells |
|
|
Term
| What does the myenteric plexus influence? |
|
Definition
|
|
Term
| What does the submucosal plexus influence? |
|
Definition
|
|
Term
| What type of R's are involved w/ the myenteric plexus? What do they do? |
|
Definition
| MechanoR's; Monitor degree of m. stretching |
|
|
Term
| What type of R's are involved w/ the Submucosal Plexus? What do they do? |
|
Definition
| ChemoR's; Monitor chemicals (nutrients, pH) |
|
|
Term
| (Myenteric Plexus): m. stretching --> ______ --> _______ --> ______ |
|
Definition
| Afferent neurons --> Cell Body --> Efferent neurons to m. cells |
|
|
Term
| (Submucosal Plexus): chemicals --> ____ --> _____ -->_____ |
|
Definition
| Afferent neurons --> Cell body --> Efferent neuron to secretory, endocrine, & mucus cells |
|
|
Term
| Many ____ exist btw Myenteric & Submucosal plexuses to coordinate ____ & ____ activity. |
|
Definition
| Interneurons/Collaterals; Muscle & Secretory |
|
|
Term
| Can endocrine cells be stimulated/inhibited by NS? |
|
Definition
| Yes (even though they are autonomous) |
|
|
Term
| Although the Enteric NS works ____, the GI tract is also innervated by ______. (= _____ & _____) |
|
Definition
| Independently; Autonomic NS; Parasympathetic & Sympathetic innervation |
|
|
Term
| What is the parasympathetic system supplied by? |
|
Definition
|
|
Term
| What type of fibers does the parasympathetic system contain? |
|
Definition
| Sensory (from ChemoR's, MechanoR's); Motor (to m. cells, gland cells) |
|
|
Term
| What is the main transmitter of the parasympathetic system? |
|
Definition
|
|
Term
| What does stimulation of the parasympathetic nn. do to GI functions? |
|
Definition
| Increases motility & secretion rates; Decreases sphincter tones |
|
|
Term
| Where does the sympathetic NS originate? |
|
Definition
|
|
Term
| Where does sympathetic NS pass to? |
|
Definition
|
|
Term
| What is the major transmitter of the SNS? |
|
Definition
|
|
Term
| Stimulation of the parasympathetic nn. mostly _____ GI functions. |
|
Definition
|
|
Term
| Stimulation of the sympathetic nn. mostly _____ GI functions. |
|
Definition
|
|
Term
| What does stimulation of the sympathetic nn. do to GI functions? |
|
Definition
| Decreases motility & secretions; Increases sphincter tone |
|
|
Term
| Enteric NS = ____ Reflexes; Autonomic NS = ____ Reflexes. |
|
Definition
|
|
Term
| Are the Enteric & Autonomic NS controlled by the same or different ChemoR's & MechanoR's w/i GI wall? |
|
Definition
|
|
Term
| What type of signals do the MechanoR's & ChemoR's send to the Enteric & Autonomic NS? |
|
Definition
|
|
Term
| What is the main stimulation for GI movements? |
|
Definition
|
|
Term
| What does distention of GI wall stimulate? Via what? |
|
Definition
| Enteric & Autonomic NS via MechanoR's |
|
|
Term
| Distension of GI wall --> Stimulation of NS via MechanoR's --> ________ |
|
Definition
| Release of Priming Factors |
|
|
Term
| What results from the release of priming factors? |
|
Definition
| Opening of ligand-gated ion channels --> Depolarization of smooth m. membranes --> Passing slow waves will reach threshold |
|
|
Term
| What happens when passing slow waves reach threshold? |
|
Definition
| Spike Potentials --> Contractions |
|
|
Term
| What does the enteric immune system consist of? |
|
Definition
| Mesenteric lnn.; Peyer's Patches; Diffuse Lymphoid Tissue; Intraepithelial Leukocytes |
|
|
Term
| What is the enteric immune system concerned w? |
|
Definition
| Potential Pathogens (Defense Sys) |
|
|
Term
| If challenged, what does the enteric immune sys do? |
|
Definition
| Releases inflammatory mediators (prostaglandins, histamine, cytokines, chemokines) |
|
|
Term
| What do prostaglandins, histamine, cytokines, etc. act as in the GI tract? |
|
Definition
| Paracrines; typically stimulating secretory & motility functions |
|
|
Term
| What does stimulation of secretory & motility functions of the GI by the enteric immune sys lead to? |
|
Definition
|
|
Term
| What is Peristaltic Rush? |
|
Definition
| Powerful & Rapid Peristaltic movements of the SI caused by intense mucosal inflammation |
|
|
Term
| What type of response is peristaltic rush? |
|
Definition
| Protective response to quickly push potentially harmful contents into the LI |
|
|
Term
| GI blood flow is largely _____. |
|
Definition
| Autoregulated & Adjusts to the level of local activity |
|
|
Term
| How much can the GI blood flow increase between inactivity & active digestion? |
|
Definition
|
|
Term
| What stimulates GI blood flow? |
|
Definition
| Pumping action of GI mvmt; Several endocrines; Decreased O2/increased CO2 conc during activity phases |
|
|
Term
| What are some endocrines that stimulate GI blood flow? |
|
Definition
|
|
Term
| Sympathetic stimulation leads to _____ of GI blood vessels. |
|
Definition
|
|
Term
| How long can GI blood vessels remain constricted w/o causing damage? |
|
Definition
|
|
Term
| What can overrule the effect of sympathetic stimulation constricting GI blood vessels? What does this do? |
|
Definition
| Autoregulatory Mechanism; Protect Mucosa |
|
|
Term
| What are some causes of long disruption of GI blood supply? |
|
Definition
| R Heart failure; Hepatosis; Ileus |
|
|
Term
| What type of tissues suffer the most from hypoxia? |
|
Definition
|
|
Term
| What is the term for blockage of the gut by a foreign object? |
|
Definition
|
|
Term
|
Definition
| Permanent distension & ingesta back-up |
|
|
Term
|
Definition
| Abdominal Pain/Discomfort |
|
|
Term
| What is another name for the cephalic phase? |
|
Definition
|
|
Term
| What does the cephalic phase involve? |
|
Definition
| Grasping, Chewing & Mixing food w/ saliva in preparation for swallowing |
|
|
Term
| What is the first step of mechanical digestion? |
|
Definition
| Cephalic phase (Mastication/Chewing) |
|
|
Term
| What type of digestion is included in the cephalic phase? |
|
Definition
| Mechanical; Chemical in some spp. (omnivores) |
|
|
Term
| Where does the cephalic phase send signals? What is the purpose of this? |
|
Definition
| Stomach, accessory glands, SI to prepare for incoming food; "warming up" |
|
|
Term
| Disturbances in _____ can hamper adequate food intake. |
|
Definition
|
|
Term
| How many pairs of salivary glands do most animals have? Name them. |
|
Definition
| 3; Parotid, Mandibular, Sublingual |
|
|
Term
| What extra salivary gland is present in ruminants & birds? |
|
Definition
|
|
Term
| What are the functions of saliva? |
|
Definition
| Moisten, lubricate, bind food into bolus; Control bacterial growth; Start carbohydrate digestion in omnivores; Cool body; Protect Mucosa; Vocalization |
|
|
Term
| How does saliva start carbohydrate digestion? |
|
Definition
|
|
Term
| How does saliva cool the body? |
|
Definition
|
|
Term
| In what animals does saliva play a role in thermoregulation? |
|
Definition
| Carnivores, Birds, Reptiles |
|
|
Term
| What do salivary acini secrete? |
|
Definition
| Mucus & plasma-like fluid (primary saliva) |
|
|
Term
| When is primary saliva altered? |
|
Definition
|
|
Term
| During duct passage, what is exchanged in saliva? |
|
Definition
|
|
Term
| Saliva is slightly ____, slightly ____, & ____-rich. |
|
Definition
|
|
Term
| What animals have slightly acidic saliva? What does this cause? |
|
Definition
|
|
Term
| In humans & horses, what is the daily volume of saliva produced? |
|
Definition
|
|
Term
| In horses, what is the daily volume of saliva produced? |
|
Definition
|
|
Term
| What is the pH of saliva? |
|
Definition
|
|
Term
| Saliva is ____ compared to plasma. |
|
Definition
|
|
Term
| What is the daily volume of saliva produced in ruminants? |
|
Definition
|
|
Term
| Salivation is ____, but greatly stimulated during _____, controlled by the _____ in 2 ways. |
|
Definition
| Continuous; Food-intake; ANS |
|
|
Term
| In what 2 ways is salivation controlled by the ANS? |
|
Definition
| Parasympathetic Reflex; Conditional Reflex |
|
|
Term
| What type of R's are involved w/ the parasympathetic salivary reflex? Where are they located? |
|
Definition
| ChemoR's & MechanoR's in the mouth (oral mucosa) |
|
|
Term
| (Parasympathetic Salivary Reflex): ChemoR's & MechanoR's in mouth --> |
|
Definition
| Salivary center/Brain stem |
|
|
Term
| Salivary center in the BS sends _____ efferents via _____ nn., causing ____. |
|
Definition
| Parasympathetic; CrN 7 & 9; Salivation |
|
|
Term
| What contributes to the conditioned salivary reflex? |
|
Definition
| Anticipation & Smell of food |
|
|
Term
| (Conditioned Salivary Reflex): Anticipation & Smell --> |
|
Definition
| Higher CNS --> Salivary Center --> Salivation |
|
|
Term
| The stimuli that cause increased salivation also activate _____ & initiate _____. |
|
Definition
|
|
Term
| Vagal reflexes lead to ___ stimulation of ____. This is called ____. |
|
Definition
| Mild; Stomach, SI, Pancreas, Bile; Warming-up Phase |
|
|
Term
| What is ruminant saliva rich in? What is this essential for? |
|
Definition
| Bicarbonate & Phosphate buffers; Neutralization of Fermentation products in the rumen |
|
|
Term
| What can the continuous production of large amounts of saliva in ruminants lead to when a foreign body is lodged in the esophagus? |
|
Definition
|
|
Term
| _____ of food req's highly coordinated mvmts of voluntary mm., using lips, tongue, teeth, forelimbs, nose. |
|
Definition
|
|
Term
| What does mastication do? |
|
Definition
| Breaks down food & lubricates it for swallowing |
|
|
Term
| What structures are involved in mastication? |
|
Definition
| Teeth, Jaws, Palate, Tongue & Cheeks |
|
|
Term
| Mastication is mainly controlled by ____, involving ___ n. |
|
Definition
|
|
Term
| What is the chewing reflex? |
|
Definition
| Presence of bolus creates pressure against palate which inhibits cheek mm.; Lower jaw drops & stimulates stretch R's in cheek mm. leading to contraction, pressure against palate, etc. |
|
|
Term
| Describe the comparative width of the jaws in carnivores. |
|
Definition
|
|
Term
| Describe the comparative width of the jaws in herbivores. |
|
Definition
| Lower jaw narrower/Upper jaw wider |
|
|
Term
| Describe the jaw movements in carnivores. |
|
Definition
| Vertical --> Cutting Action |
|
|
Term
| Describe the jaw movements in herbivores. |
|
Definition
| Horizontal & Vertical --> Grinding Action |
|
|
Term
| What is another word for swallowing? |
|
Definition
|
|
Term
| What phases are involved in swallowing? |
|
Definition
|
|
Term
| The voluntary + reflex phases of swallowing guarantee _____. |
|
Definition
| Correct closure of nasal & tracheal passageways |
|
|
Term
| What can occur if the nasal & tracheal passageways do not close during swallowing? |
|
Definition
| Fatal Aspiration Pneumonia |
|
|
Term
| What is the voluntary phase of swallowing? |
|
Definition
| Tongue moves bolus into pharynx |
|
|
Term
| What is the 1st step of the reflex phase of swallowing? |
|
Definition
| Touch R's stimulate swallowing center (MO) via CrN 9 (Gag Reflex) |
|
|
Term
| What does the gag reflex initiate? |
|
Definition
| Lifting of soft palate & closure of larynx; peristaltic wave moves over pharynx; upper esophageal sphincter relaxes; Bolus enters esophagus |
|
|
Term
| What m. is the esophageal sphincter a part of? |
|
Definition
|
|
Term
| In the esophageal phase of swallowing, the bolus is propelled by ____ towards ____. |
|
Definition
|
|
Term
| _______ relaxes ahead of peristalsis to allow entry of bolus into stomach. |
|
Definition
| Lower esophageal sphincter |
|
|
Term
| When not in swallowing process, ______ are tightly closed to avoid entry of air & esophageal reflux of gastric contents. |
|
Definition
| Upper & Lower Esophageal Sphincters |
|
|
Term
| What nerve is tested by the gag reflex? |
|
Definition
|
|
Term
| How common are disturbances in pregastric digestion? |
|
Definition
|
|
Term
| What can result from disturbances of pregastric digestion? |
|
Definition
| Reduced nutrient intake &/or insufficient mechanical preparation of food. |
|
|
Term
| What are some examples of pregastric disturbances related to teeth problems or injuries of oral mucosa? What is often caused? |
|
Definition
| Broken teeth, Enamel points, Plaque/Inflammations; "Woody Tongue;" Pain |
|
|
Term
| What are some examples of pregastric disturbances related to nerve or CNS damage? |
|
Definition
| Encephalitis, Tetanus, Rabies, Trigeminal Paralysis |
|
|
Term
| What is blocked during deep anesthesia? |
|
Definition
|
|
Term
| What are 4 causes of megaesophagus? |
|
Definition
| Achalasia; PRAA; MG; Idiopathic |
|
|
Term
|
Definition
| Lower esophageal sphincter fails to relax due to genetic malfunction of myenteric plexus |
|
|
Term
| PRAA --> ____ of esophagus |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| What m. is innervated by the trigeminal n? What results from damage to this n? |
|
Definition
|
|
Term
| Rabies --> ____ m. paralysis |
|
Definition
|
|
Term
| What is the most common disturbance of pregastric digestion related to? |
|
Definition
|
|
Term
| Regurgitation is from _____, where as vomiting is from ____. |
|
Definition
|
|
Term
| What are the 4 functions of the stomach? |
|
Definition
| Temporary Storage of food; Mixing of food w/ gastric secretions & liquefaction of ingesta into chyme; Chemical & enzymatic digestion; Controlled release of liquefied chyme into SI |
|
|
Term
| What is particularly digested by chemical & enzymatic means in the stomach? |
|
Definition
|
|
Term
| What part of the stomach stores food? |
|
Definition
| Proximal (Cardia & Fundus) |
|
|
Term
| Is absorption a physiological gastric function? |
|
Definition
|
|
Term
| Can any substances be absorbed by the stomach? |
|
Definition
| Yes, but not natural diet/nutrients; Alcohol, small lipophilic drugs |
|
|
Term
| What is required before chyme can be passed on to the duodenum? |
|
Definition
| Thorough mixing w/ gastric juices |
|
|
Term
| The duodenum has a limited capacity. What does this necessitate? |
|
Definition
|
|
Term
| Where does storage of food mostly occur? Facilitated by what? |
|
Definition
| Proximal stomach; Accommodation reflex |
|
|
Term
| What is the accommodation reflex? |
|
Definition
| Food enters the stomach & stimulates mechanoRs which initiate a vago-vagal reflex |
|
|
Term
| What is the vago-vagal reflex of the accommodation reflex? |
|
Definition
| Reduction in m. tone in proximal parts of stomach --> Relaxation --> Expansion of stomach w/o pressure increase |
|
|
Term
| What is most likely the NT of the vago-vagal reflex? |
|
Definition
|
|
Term
| What reduces the accommodation reflex? |
|
Definition
| Suppression of vagus or Stimulation of Sympathetic sys --> Increased gastric pressure after food intake --> Satiety feeling |
|
|
Term
|
Definition
| Vasoactive Intestinal Peptide |
|
|
Term
| In what part of the stomach does mixing occur? |
|
Definition
|
|
Term
| What type of foods require grinding & mixing? |
|
Definition
|
|
Term
| What are semi-solid & solid foods mixed with in the distal stomach? |
|
Definition
|
|
Term
|
Definition
| Strong, sleeve-like sphincter |
|
|
Term
| What does presence of food in the distal stomach stimulate? |
|
Definition
| Local & Central Reflexes --> Enhance peristalsis originating in pacemaker area |
|
|
Term
| Peristalsis originating in the pacemaker area of the distal stomach travel towards the _____. |
|
Definition
|
|
Term
| What happens when peristalsis reaches the antrum? |
|
Definition
| Pylorus contracts ahead of peristaltic wave --> Content is kneaded & squirted back (Retropulsion) |
|
|
Term
| What does mixing in the distal stomach do to content? |
|
Definition
|
|
Term
| When content of the distal stomach is liquefied, peristalsis begins to include _____ & becomes ____. |
|
Definition
| Prox stomach; More Intense |
|
|
Term
| When peristalsis includes the proximal stomach, small amounts of ____ are passed through the _____ ahead of strong peristaltic waves & chyme enters _____. |
|
Definition
|
|
Term
| How long after a solid meal until the stomach is empty? |
|
Definition
|
|
Term
| What occurs during fasting phases/empty stomach? What is this called? |
|
Definition
| Occasional strong peristaltic waves btw stomach & ileum while pylorus is relaxed; Migrating Motility Complex |
|
|
Term
|
Definition
| Migrating Motility Complex |
|
|
Term
| What initiates the MMC? What does the MMC do? |
|
Definition
| Motilin; Clear stomach & SI of undigested food particles |
|
|
Term
| How long does a ferret take from eating to defecation? |
|
Definition
|
|
Term
| What can be done <30 min after a foreign object is ingested? |
|
Definition
|
|
Term
|
Definition
| Distension, Pain, Unstoppable Vomiting |
|
|
Term
| What is another name for the MMC? |
|
Definition
|
|
Term
| How many types of mucosa does the stomach contain? What are they? |
|
Definition
| 2; Non-Glandular & Glandular |
|
|
Term
| What is another name for non-glandular mucosa of the stomach? |
|
Definition
|
|
Term
| What is the function of the non-glandular stomach? |
|
Definition
| Unclear (Storage/Fermentation?) |
|
|
Term
| What monogastric has a particularly large non-glandular stomach? |
|
Definition
|
|
Term
| What is the glandular mucosa of the stomach composed of? |
|
Definition
| Cardiac, Parietal, & Pyloric Region which contain tubular glands |
|
|
Term
| What type of cells are in the glandular mucosa of the stomach? |
|
Definition
| Mucus, Parietal, Enterochromaffin-like, Chief, & G (Endocrine) Cells |
|
|
Term
| What type of cells are in the glandular mucosa of the stomach? |
|
Definition
| Mucus, Parietal, Enterochromaffin-like, Chief, & G (Endocrine) Cells |
|
|
Term
| What are the mucus cells of the stomach? How many are there? |
|
Definition
| Surface & Neck cells; Very numerous |
|
|
Term
| What do parietal cells of the stomach secrete? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What do enterochromaffin-like cells secrete? |
|
Definition
|
|
Term
| What do chief cells secrete? |
|
Definition
| Pepsinogen or Prochymosin |
|
|
Term
| What do G/Endocrine Cells secrete? Where are they present? |
|
Definition
| Gastrin; Pyloric Region only |
|
|
Term
| What are very numerous throughout the GI mucosa, enabling continual replenishment of all GI cells? |
|
Definition
|
|
Term
| Stem cells give the GI mucosa a high _______. |
|
Definition
|
|
Term
| The mucus layer is absolutely essential to protect the gastric mucosa against _________. |
|
Definition
| Mechanical stress, Acids, Digestive enzymes, Diffusion of damaging chemicals |
|
|
Term
| What is mucus produced by? |
|
Definition
| Mucus/Goblet cells covering the entire glandular mucosa |
|
|
Term
|
Definition
| A coat of highly viscous, adherent, nearly insoluble mucins |
|
|
Term
| What are mucins? What do they provide? |
|
Definition
| Glycoproteins; Protection against mechanical stress & diffusion of damaging chemicals |
|
|
Term
| Is mucus acidic or alkaline? Why? |
|
Definition
| Alkaline, contains bicarbonate = protection against protons |
|
|
Term
| What controls mucus secretion? |
|
Definition
| Local Reflexes (Enteric NS) & Central Reflexes (Vagus) |
|
|
Term
| What increases mucus & bicarbonate release? |
|
Definition
| Synthesis of Prostaglandin (PGE2) in goblet cells |
|
|
Term
|
Definition
|
|
Term
| Drugs interfering w/ PG synthesis will affect _____. |
|
Definition
|
|
Term
| NSAIDs interfere _____ w/ ______, leading to ______. |
|
Definition
| Non-selectively, PGs; decreased mucus layer & protection, ulcers, erosion, inflammation |
|
|
Term
| Parietal cells secrete into the stomach lumen a(n) ______ sol'n of pH _____. |
|
Definition
|
|
Term
| What is involved w/ parietal cell secretion of isotonic sol'n? |
|
Definition
| Proton Pump (H+/K+ exchanger) |
|
|
Term
| What are the functions of HCl? |
|
Definition
| Macerate ingesta into fluid, Denature proteins, Begin emulsification of fats, Activate proteolytic enzymes pepsinogen or prochymosin, Bactericidal |
|
|
Term
| Stimulation of parietal cells --> |
|
Definition
|
|
Term
| What are some factors that stimulate parietal cells? |
|
Definition
|
|
Term
| ACh is released via ____ & ____ reflexes. |
|
Definition
|
|
Term
| What is one of the main stimulators of the gut? |
|
Definition
|
|
Term
| Gastrin is released from _____ into ____ in response to ____ (____ stimulus). |
|
Definition
| G Cells; Blood; Peptides (mild direct stimulus) |
|
|
Term
| Histamine is released from _______ (= ____stimulus) in response to _____. |
|
Definition
| Enterochromaffin-like cells; Strong; Gastrin |
|
|
Term
| What is the pH of the stomach in pigs & humans? In carnivores? |
|
Definition
|
|
Term
| Fats must be _____ for enzymes to work on them. |
|
Definition
|
|
Term
| What is one of the main factors in combating incoming pathogens? |
|
Definition
|
|
Term
| Pepsinogens are precursors of _____. |
|
Definition
|
|
Term
| Activation from pepsinogens to pepsins req's ______ environment. |
|
Definition
|
|
Term
| Pepsins' pH optimum lies btw _____. |
|
Definition
|
|
Term
| What type of enzymes are pepsinogens? |
|
Definition
| Proteolytic --> Initiate protein digestion |
|
|
Term
| How do pepsinogens hydrolyze collagen? |
|
Definition
| Splitting large polypeptides into smaller polypeptides & some oligopeptides |
|
|
Term
| How many peptides are in an oligopeptide? |
|
Definition
|
|
Term
| Nursing animals secrete ______ instead of pepsinogen, which is specific for _____. |
|
Definition
| Prochymosin (Rennin in calves); Coagulation of casein |
|
|
Term
| IF is released from ____ cells & co-secreted w/ _____. |
|
Definition
|
|
Term
| What is IF essential for? |
|
Definition
| Intestinal absorption of Vit B12 (necessary cofactor for erythropoiesis) |
|
|
Term
| Suppression of HCl & IF can lead to _____. |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is the purpose of tight control of gastric motility & secretions? |
|
Definition
| Prepare stomach for incoming food; Match rate of gastric secretions & grinding w/ quantity & quality of ingested food; Match emptying of chyme w/ digestive & absorptive capacity of SI |
|
|
Term
| What are the 3 components of the gastric motility/secretion control system? |
|
Definition
| Cephalic Phase, Gastric Phase, Intestinal Phase |
|
|
Term
| What is the cephalic phase of the stomach? |
|
Definition
| Anticipation of food, smell, taste, or touch stimulate Vagus, which mildly stimulates gastric motility & secretions |
|
|
Term
| Describe motility & secretions in the cephalic phase in the stomach. |
|
Definition
| Proximal relaxation/distal peristalsis; Mucus, Gastrin, Histamine, HCl, Pepsinogen |
|
|
Term
| How much stomach juice do humans produce each day? |
|
Definition
|
|
Term
| What is the gastric phase of the stomach? |
|
Definition
| Arrival of food in stomach --> Stimulation of gastric mechano- & chemoRs --> Strong stimulation of local (plexus) & central (vagal) reflexes |
|
|
Term
| What are the effects of the gastric phase on the stomach? |
|
Definition
| Relaxation of mm. (accommodation) in proximal parts; Vigorous m. contractions (mixing/grinding) in distal parts; Strong stimulation of all gastric secretions w/ massive HCl release |
|
|
Term
| Describe the self-limitation of the gastric phase in the stomach. |
|
Definition
| When pH <2, gastrin release becomes blocked & vagal & local reflexes become inhibited to prevent excessive acidification |
|
|
Term
| When gastrin is blocked, ____ & ____ are subsequently blocked. |
|
Definition
|
|
Term
| The SI has a ____ capacity. |
|
Definition
|
|
Term
| What is the intestinal phase of digestion? |
|
Definition
| Chyme arrives in duod --> inhibition of gastric glands & motility due to activation of R's in SI to prevent overloading of SI (Negative feedback) |
|
|
Term
| What are the stimuli of the intestinal phase? |
|
Definition
| Distension of SI, High Acidity, High Nutrient Content, Irritation of Mucosa (Enterogastric Reflex) |
|
|
Term
| Intestinal phase is transmitted largely by ______. |
|
Definition
|
|
Term
| What endocrines are involved w/ the intestinal phase? |
|
Definition
|
|
Term
| What stimulates secretin, & what does secretin do? |
|
Definition
| Low pH; Reduces gastric secretions |
|
|
Term
|
Definition
|
|
Term
| What stimulates CCK & what does it do? |
|
Definition
| Fats & Proteins; Reduces gastric motility |
|
|
Term
|
Definition
| The forceful expulsion of stomach/SI contents through the mouth |
|
|
Term
| Vomiting involves coordination of _____. |
|
Definition
|
|
Term
| Coordination of m. groups in vomiting: |
|
Definition
| Contraction of duod, Closure of pylorus, Gastric wall & Cardia relax, Abd mm. contract, Diaphragm fixed, Reversal of swallowing |
|
|
Term
| Vomiting is a reflex under the control of the _____. |
|
Definition
| Vomiting Center in the brain stem |
|
|
Term
| The vomiting center receives afferent signals from: |
|
Definition
| GI mechano- & chemoR's, Viscera other than GI tract, Extramedullary centers (psychogenic), ChemoR trigger zones |
|
|
Term
| What is one factor that stimulates GI mechano- & chemoR's leading to vomiting? |
|
Definition
|
|
Term
| What are some factors that stimulate vomiting via viscera other than GI tract? |
|
Definition
| Inflammation of liver & kidneys |
|
|
Term
| In what animals is extramedullary cortex/psychogenic center a factor in vomiting? |
|
Definition
|
|
Term
| What stimulates the ChemoR trigger zone of the vomiting center? |
|
Definition
| Drugs, Toxins, Inflammation products |
|
|
Term
| Is regurgitation voluntary? Vomiting? |
|
Definition
|
|
Term
| What are some consequences of severe vomiting? |
|
Definition
| Loss of fluid, Loss of K+, Loss of H+ |
|
|
Term
| What results from loss of fluid? |
|
Definition
| Hypovolemia, decrease BP, Circulatory Shock |
|
|
Term
| What results from loss of K+? |
|
Definition
| Hypokalemia, Hyperpolarization of membranes, Reduced excitability of n/m cells, Weakness & Hyporeflexia |
|
|
Term
| What results from loss of H+? |
|
Definition
| Metabolic Alkalosis & Hypoventilation |
|
|
Term
| Why is vomiting nearly impossible in horses? |
|
Definition
| Acute angle btw esophagus/stomach & clamp-like structure of diaphragm --> danger of stomach rupture |
|
|
Term
| During vomiting, what happens to protect the respiratory tract? |
|
Definition
| Soft palate lifts, Trachea & Epiglottis close |
|
|
Term
| What can be used to induce vomiting? Examples? |
|
Definition
| ChemoR trigger zone; morphine, xylazine in cats |
|
|
Term
| What ceases to function in the absence of K+? |
|
Definition
|
|
Term
|
Definition
| The GI mucosa forms a barrier btw the gut lumen & body, allowing transfer of nutrients while protecting the body against harmful chemicals & bacteria |
|
|
Term
| What are the components of the GI barrier? |
|
Definition
| Mucus & bicarbonate, PGE2, Epithelial cells w/ tight junctions & stem cells, Bactericidal peptides/IgA |
|
|
Term
| What do mucus & bicarbonate do in the GI barrier? |
|
Definition
| Coat cells, neutralize acids, bind to bacteria |
|
|
Term
| What does PGE2 do in the GI barrier? |
|
Definition
| Increase blood flow, mucus, & bicarb secretions |
|
|
Term
| What do stem cells do in the Gi barrier? |
|
Definition
| Supply high regenerative capacity |
|
|
Term
| What do the tight junctions btw epithelial cells do in the GI barrier? |
|
Definition
| Make tract impenetrable to large particles |
|
|
Term
| What is the #1 cause of disruptions to the GI barrier? |
|
Definition
|
|
Term
| What are some causes of disruptions to the GI barrier? |
|
Definition
| Stress, NSAIDs, Ischemia, Infections |
|
|
Term
| How does stress disrupt the GI barrier? |
|
Definition
| Sympathetic stimulation & cortisol release --> reduced blood flow, mucus, HCO3, healing |
|
|
Term
| What, in particular, does cortisol impede? |
|
Definition
|
|
Term
|
Definition
| Total lack of blood supply |
|
|
Term
| How does ischemia disrupt the GI barrier? |
|
Definition
|
|
Term
| How do infections disrupt the GI barrier? What is one such infection? |
|
Definition
| Tissue damage; Helicobacter pylori |
|
|
Term
| What are consequences of disruption of the GI barrier? |
|
Definition
| Cell injury, Gastritis, Auto-digestion, Erosion, Ulceration, Enteritis |
|
|
Term
|
Definition
|
|
Term
| What is the Tx for disruption of the GI barrier? |
|
Definition
| Stress relief, Histamine (H2) blockers, Proton pump blockers, Antibiotics |
|
|
Term
|
Definition
|
|
Term
| Give 2 examples of NSAIDs |
|
Definition
|
|
Term
| What are some causes of stress in animals? |
|
Definition
| Transportation, Food changes, Dz, Abnormal feeding patterns |
|
|
Term
| What is a major damaging factor in the stomach? |
|
Definition
|
|
Term
| What is the pH of chyme entering the SI? |
|
Definition
|
|
Term
| When leaving the stomach, chyme is a fluid mixture of: |
|
Definition
| Polypeptides (via action of HCl & pepsins), Large emulsified fat globules (via action of HCl), Unchanged dietary carbohydrates (respectively some oligosaccharides in omnivores via salivary amylase) |
|
|
Term
| Can chyme that leaves the stomach be absorbed in the SI? |
|
Definition
|
|
Term
| What 2 events must occur to chyme leaving the stomach? |
|
Definition
| Neutralization of gastric acid; Hydrolysis of macromolecules into micromolecules |
|
|
Term
| Why must neutralization of gastric acid in the chyme leaving the stomach take place? |
|
Definition
|
|
Term
| Why must macromolecules be hydrolyzed into micromolecules? |
|
Definition
| For absorption (Monosaccharides, tri/dipeptides and aa's & FFAs/monoglycerides) |
|
|
Term
| To achieve neutralization of gastric acid & hydrolysis of macromolecules, _____, _____, & _____ must cooperate. |
|
Definition
| Pancreas, Bile, & SI Mucosa |
|
|
Term
| What does the pancreas provide for chyme leaving the stomach? |
|
Definition
| Buffers & Major digestive enzymes |
|
|
Term
| What does bile provide for chyme leaving the stomach? |
|
Definition
|
|
Term
| What does the SI mucosa provide for chyme leaving the stomach? |
|
Definition
| Buffers, Final digestive enzymes, Absorptive mechanisms |
|
|
Term
| What mildly stimulates the exocrine pancreas to secrete enzymes & bicarb ("warming up")? Via what? |
|
Definition
| Cephalic phase via vagal stimulation & Gastric phase via gastrin release |
|
|
Term
| What is the main phase of pancreatic stimulation? |
|
Definition
|
|
Term
| The intestinal phase stimulates the pancreas via _______ |
|
Definition
|
|
Term
| wrt pancreatic stimulation, what role does Secretin play? |
|
Definition
| Released from duodenal endocrine cells into blood when pH of chyme is low (<4.5) --> Stimulates bicarb secretion |
|
|
Term
| wrt pancreatic stimulation, what role does CCK play? |
|
Definition
| Proteins & fats stimulate release of CCK from duodenal endocrine cells into blood --> Stimulates release of pancreas enzymes |
|
|
Term
| How much pancreatic fluid do humans produce per day? |
|
Definition
|
|
Term
| What are the direct digestive functions of the liver? Via what? |
|
Definition
| Facilitate digestion & absorption of fats & lipophilic vitamins via secretion of bile acids; Neutralize acidic chyme via bicarb secretion |
|
|
Term
| What are the fat soluble vitamins? |
|
Definition
|
|
Term
| What cell types secrete bile juices? |
|
Definition
|
|
Term
| What type of bile juices do hepatocytes secrete? |
|
Definition
| Bile acids (>50% of solutes); Lipophilic waste products (bile pigments/bilirubin, cholesterol) |
|
|
Term
| What type of bile juices do duct cells secrete? |
|
Definition
| Bicarb, Electrolytes & Water |
|
|
Term
| Where is bile juice temporarily stored? Until when? Which animals lack this structure? |
|
Definition
| Gall Bladder; Until needed; Horses, Deer, Elephants, Giraffes |
|
|
Term
| What happens in horses since they lack a GB? |
|
Definition
| Continuous absorption of electrolytes & water leads to concentration of organic compounds |
|
|
Term
| What does the gall bladder do to bile? |
|
Definition
|
|
Term
| What are bile acids derived from? |
|
Definition
|
|
Term
| Cholesterol --> ____ --> ____ |
|
Definition
| Cholic acid --> Conjugated w/ aa's |
|
|
Term
| What aa's is cholic acid conjugated w/? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Detergent has a ______ & _____ end. |
|
Definition
|
|
Term
| What are the functions of bile acids? |
|
Definition
| Emulsification & Transport |
|
|
Term
| Where do bile acids attach to fat globules? |
|
Definition
|
|
Term
| Bile acids attach to fat globules --> ______ --> _____ |
|
Definition
| Vigorous mixing in aqueous chyme --> Globules break up into smaller pieces |
|
|
Term
| What does breaking up of fat globules into smaller pieces accomplish? |
|
Definition
| Increases SA for action of pancreatic lipases |
|
|
Term
| After hydrolysis by lipases, fatty acids & monoglycerides form _____ w/ _____ (=____). |
|
Definition
| Aggregates; Bile Acids; Micelle |
|
|
Term
| Micelles have ___ ends pointing outward & ____ ends pointing inward. |
|
Definition
|
|
Term
| What is the importance of having the lipophilic ends inside the micelle? |
|
Definition
| Keeps lipids in sol'n & enables their transport w/i aqueous chyme |
|
|
Term
| Micelle formation allows for _____. |
|
Definition
| Transport to & absorption from mucosa |
|
|
Term
| Some bile juice is released during ______ phase(s). The main stimulation occurs during _____ phase(s). |
|
Definition
| Cephalic & Gastric; Intestinal |
|
|
Term
| The main stimulation of bile juice release occurs during the intestinal phase via what hormones? |
|
Definition
|
|
Term
| wrt bile release, CCK stimulates _____. |
|
Definition
| Gall bladder contraction & release of stored bile |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| In animals w/o GB, the ____ is not an efficient barrier & bile is continuously release into duod. |
|
Definition
|
|
Term
| wrt bile secretion, what does secretin stimulate? |
|
Definition
| Bicarb secretion into bile system when pH of chyme is low |
|
|
Term
| Secretion of pancreatic & bile juices are _____. |
|
Definition
|
|
Term
| What % of bile acids are reabsorbed? Where? |
|
Definition
|
|
Term
| Once reabsorbed, where do bile acids re-enter? |
|
Definition
|
|
Term
| Bile acids are recycled and secreted again & again up to _____ times. |
|
Definition
|
|
Term
| What % of bile acids are shed w/ feces? |
|
Definition
|
|
Term
| What is the choleretic effect of bile acids? |
|
Definition
| Re-uptake of bile acids stimulates hepatocytes to secrete more bile juice (positive feedback) |
|
|
Term
| What are damaged hepatocytes incapable of? What does this lead to? |
|
Definition
| Extracting bile acids from portal blood; Bile acids may increase in plasma |
|
|
Term
| What is one diagnostic indicator of liver dz? |
|
Definition
| Increased bile acids in plasma |
|
|
Term
| Inflammation of the pancreas leads to liberation of _______,which are then in contact w/ digestive enzymes leading to ___ & ___. |
|
Definition
| Proteolytic enzymes; Activation & Autodigestion |
|
|
Term
| What is found PM when an animal had pancreatitis? |
|
Definition
|
|
Term
| How common are GB inflammation & stones in vet med? |
|
Definition
|
|
Term
| Typically, bile issues are secondary to _____. |
|
Definition
|
|
Term
| What is the strongest stimulator of HCl secretion from parietal cells? |
|
Definition
|
|
Term
| Gastrinoma leads to increased secretion of ____, which causes increased production of _____ & _____. |
|
Definition
| Gastrin; HCl; Corrosion, Erosion, Ulcers |
|
|
Term
| What can be used to decrease or stop HCl production? |
|
Definition
|
|
Term
| Gastrin stimulates ___ cells to secrete ____. |
|
Definition
| ECL, Histamine; Parietal, HCl |
|
|
Term
| What is the center of the food processing plant? |
|
Definition
|
|
Term
| Where are macronutrients digested & absorbed as simple molecules? |
|
Definition
|
|
Term
| What are the main tasks of the SI? |
|
Definition
| Receive, mix, & propel chyme, pancreatic enzymes, bile juice, & buffers; Add lg volumes of buffered fluid; Provide add'l means to finalize digestive process started by gastric & pancreatic enzymes (i.e. its mucosal enzymes); Absorb virtually all micromol's & the majority of H2O & electrolyes |
|
|
Term
| What does the large volume of buffered fluid added by the SI do? |
|
Definition
| Create a suitable aqueous dilution enabling digestion & absorption |
|
|
Term
| Where is chemical digestion finalized? |
|
Definition
|
|
Term
| Digestive enzymes work via _____, therefore need ____. |
|
Definition
| Hydrolysis; Aqueous medium |
|
|
Term
| Should nutrients go through to the LI? |
|
Definition
|
|
Term
| What is stimulated in the SI by incoming chyme? |
|
Definition
| Mixing & Peristaltic Contractions |
|
|
Term
| What do contractions in the SI assist in? |
|
Definition
| Mixing incoming chyme w/ intestinal fluid, pancreatic juice & bile; Distributing chyme along SI; Enabling contact btw digestive products & absorptive cells |
|
|
Term
| What does the ileocecal sphincter do? |
|
Definition
| Controls flow of ingesta btw SI &LI; Impede flow of ingesta into LI during digestive phase/active digestion (Closed); Avoid backflow of bacteria from LI into SI |
|
|
Term
| The ileocecal sphincter is a "____" btw SI & LI. |
|
Definition
|
|
Term
| The ileocecal sphincter is a ___-way valve. |
|
Definition
|
|
Term
| Are there a lot of bacteria in the SI, LI, or both? |
|
Definition
|
|
Term
| What can result from backward flow through the ileocecal sphincter? |
|
Definition
| SIBO (SI Bacterial Overgrowth) |
|
|
Term
| What are the SI tube & its mucosa characterized by? |
|
Definition
| Vast increase in SA by having folds, villi, & microvilli (600 fold increase) |
|
|
Term
| What is the purpose of the Brush Border & Microvilli? |
|
Definition
| Increase SA for absorption |
|
|
Term
| The intestinal mucosa contains numerous stem cells found w/i the _______. |
|
Definition
|
|
Term
| What type of SI cells do stem cells differentiate into? |
|
Definition
|
|
Term
| How often is the SI mucosa replaced? |
|
Definition
|
|
Term
| What are the consequences of stem cells in the SI mucosa? |
|
Definition
| Great regenerative capacity after injury; Highly active tissue, thus vulnerable to hypoxia, metabolic disturbances, some viral inf's |
|
|
Term
| How long does it typically take for diarrhea to clear itself? |
|
Definition
|
|
Term
| What does Parvo virus affect? |
|
Definition
| Stem cells in Crypts of Lieberkuhn --> Loss of mucosal lining |
|
|
Term
| What do stem cells of the SI first differentiate into? Then? |
|
Definition
| Young enterocytes (Secretory Cells); Mature Enterocytes (Absorptive Cells) |
|
|
Term
| As young enterocytes of SI divide, they migrate _____. |
|
Definition
|
|
Term
| Where are the young enterocytes of the SI? |
|
Definition
| Lining Crypts of lieberkuhn |
|
|
Term
| Where are the mature enterocytes of the SI? |
|
Definition
|
|
Term
| After how long do mature enterocytes excoriate? To where? |
|
Definition
| ~5 days --> Gut lumen to be digested |
|
|
Term
| Aside from enterocytes, what do SI stem cells differentiate into? |
|
Definition
| Endocrine cells, mucus cells, paneth cells |
|
|
Term
| What do endocrine cells of the SI produce? |
|
Definition
| Endocrines (CCK, Secretin) |
|
|
Term
| What cells are the "body guard" in close proximity to SI stem cells? |
|
Definition
|
|
Term
| Paneth cells are ____. They secrete ____ & ____. |
|
Definition
| Protective; Bactericidal substances & Ab |
|
|
Term
| Some toxins (E. coli, Cholera), inflammatory mediators & viruses stimulate _____ transport --> massive _______ --> severe ______. |
|
Definition
| Cl- Transport; Secretion of fluid into gut; Secretory Diarrhea |
|
|
Term
| What do young enterocytes of SI secrete? For what? |
|
Definition
| Lg volumes of intestinal fluid to facilitate digestion & absorption through active Cl- secretion into gut lumen |
|
|
Term
| What does active Cl- secretion into the SI lumen create? |
|
Definition
| Electrical Gradient which pulls Na+ |
|
|
Term
| What does the pull of Na+ into the SI lumen create? |
|
Definition
| Osmotic Gradient which pulls water |
|
|
Term
| How much H2O is osmotically pulled into the SI lumen each day in humans? |
|
Definition
|
|
Term
| What does the osmotically pulled H2O do in the SI lumen? |
|
Definition
|
|
Term
| What do mature enterocytes develop? |
|
Definition
| Numerous Microvilli called BBM |
|
|
Term
|
Definition
|
|
Term
| What does the BBM contain? |
|
Definition
| Digestive enzymes & absorptive mechanisms |
|
|
Term
| What is the most powerful toxin that causes secretory diarrhea? |
|
Definition
|
|
Term
| What cells in the SI create an NaCl sol'n? |
|
Definition
|
|
Term
| What animals are more vulnerable to E. coli? |
|
Definition
|
|
Term
| What cells of the SI finalize digestion & absorption of micronutrients? |
|
Definition
|
|
Term
| Through mixing/peristaltic action, Mature enterocytes of the SI come into contact w/ end products of _______. |
|
Definition
|
|
Term
| What are the end products of luminal digestion? |
|
Definition
| Salivary, Gastric, & Pancreatic Enzymes |
|
|
Term
| The end-products of luminal digestion are largely ______, & must be _____ by ____. |
|
Definition
| Non-absorbable; Hydrolyzed further by BBM enzymes |
|
|
Term
| What is hydrolysis of luminal digestion end-products by BBM enzymes? |
|
Definition
|
|
Term
| Where are carbohydrates digested? |
|
Definition
|
|
Term
| What is the storage form for sugar in animals? |
|
Definition
|
|
Term
| What is the storage form of sugar in plants? |
|
Definition
|
|
Term
| What is the most common carbohydrate? |
|
Definition
|
|
Term
| What type of carbohydrate is starch & glycogen? |
|
Definition
| Polysaccharide consisting of glucose in alpha-1-4 & alpha-1-6 (branched) glycosidic linkages |
|
|
Term
| What are the phases of glycogen & starch digestion? |
|
Definition
| Luminal Phase (Salivary, Pancreatic enzyme) & Brushborder Phase |
|
|
Term
| Luminal Phase of starch/glycogen digestion: |
|
Definition
| alpha-amylase hydrolyzes only alpha-1-4 linkages; products are oligo- & some disaccharides (mostly maltase), which cannot be absorbed |
|
|
Term
| Brushborder phase digestion of starch/glycogen: |
|
Definition
| Oligo- & disaccharidases w/i BBM (eg by maltose) hydrolyze alpha-1-4 & alpha 1-6 linkages; endproducts are monosaccharides (Glc) = absorbable |
|
|
Term
| The end products of which phase of starch/glycogen digestion are absorbable? |
|
Definition
|
|
Term
| Can alpha amylase hydrolyze disaccharides? |
|
Definition
|
|
Term
| What is req'd to digest disaccharides? |
|
Definition
|
|
Term
| What is req'd to digest sucrose? What is it digested into? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is req'd for digestion of lactose? What is it digested into? |
|
Definition
|
|
Term
| What is the only carb-digesting enzyme in neonates? |
|
Definition
|
|
Term
| When does BBM lactase activity decline? |
|
Definition
|
|
Term
| Many adults are sensitive to _____. |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is lactose intolerance? |
|
Definition
| Genetic lactase deficiency in kittens & humans; Lactose is fermented to lactic acid --> Mucosal irritant --> Diarrhea |
|
|
Term
| What happens to alpha amylase in the stomach? |
|
Definition
| Destroyed by HCl & pepsinogens |
|
|
Term
| In what part of the stomach does alpha-amylase continue to function in humans & pigs? |
|
Definition
|
|
Term
| What % of carb digestion occurs in the mouth & prox stomach in humans & pigs? |
|
Definition
|
|
Term
| Absorption of Glc & Gal into absorptive cells occurs via _______. |
|
Definition
| Secondary active Na-cotransport mechanism |
|
|
Term
| Secondary active Na-cotransport mechanism d/o _______ |
|
Definition
| Electrochemical sodium gradient created by Na/K pump @ the basolateral side |
|
|
Term
| What is an exception to Secondary active Na-cotransport mechanism for monosaccharide absorption? |
|
Definition
| Fructose is absorbed via facilitated diffusion |
|
|
Term
| What occurs w/ monosaccharides @ the basolateral membrane? |
|
Definition
| Leave enterocytes by FD into interstitium --> Diffuse into blood --> Tissues |
|
|
Term
| How are structural carbohydrates digested? Why? |
|
Definition
| Fermented by microbial action; Can't be hydrolyzed by any mammalian enzyme |
|
|
Term
|
Definition
|
|
Term
|
Definition
| No; Needs Carrier molecule |
|
|
Term
| Proteins must be converted into _____ for absorption. |
|
Definition
| Tri- or dipeptides, or aa's |
|
|
Term
| What are the 2 phases of peptide absorption? |
|
Definition
|
|
Term
| Which transporter is not inhibited by enterotoxins? |
|
Definition
|
|
Term
| What is the luminal phase of protein digestion? |
|
Definition
| HCl denatures proteins & activates pepsin; Pepsin hydrolyzes proteins into polypeptides; Pancreatic endo- & exopeptidases hydrolyze polypeptides into oligopeptides |
|
|
Term
| What is the BBM phase of protein digestion? |
|
Definition
| Brushborder enzymes hydrolyze oligopeptides into tri- & dipeptides & aa's |
|
|
Term
| Neonates of some species absorb colostral Ig's by endocytosis. Digestion of these proteins is avoided by: |
|
Definition
| Limited HCl secretion; Limited pro-chymosin secretion; Trypsin-inhibitor in colostrum |
|
|
Term
| How are aa's & di- & tripeptides absorbed? |
|
Definition
| Similar mechanisms as Glc (Secondary Active Na-Cotransport) |
|
|
Term
| Absorption of the end products of carb & protein digestion d/o in tact _____, needs specific _____, d/o ______ & req's _____. |
|
Definition
| Enterocytes, Specific Transporters, Na absorption, energy |
|
|
Term
| What does digestion/absorption of fats d/o? |
|
Definition
| Pancreatic enzymes & bile salts (does not req BB enzymes or transporters) |
|
|
Term
| Fat globules are emulsified by _____. |
|
Definition
|
|
Term
| What attaches to the surface of fat globules? What does it do? |
|
Definition
| Pancreatic lipase/Colipase; Hydrolyze triglycerides into monoglycerides & FFAs |
|
|
Term
| Monoglycerides & FFAs form aggregates w/ ______ (=_____). |
|
Definition
| Conjugated bile acids (Micelles) |
|
|
Term
| Micelles transport _______ to ______ where they _____ into ______. |
|
Definition
| Monoglycerides & FFAs to BBM; Diffuse into epithelial cell |
|
|
Term
| Free conjugated bile acids return to _________. |
|
Definition
| Emulsify more fat globules or form new micelles |
|
|
Term
| What happens to FFAs & monoglycerides after diffusion into enterocyte? |
|
Definition
| Mostly recombined to triglycerides |
|
|
Term
| What aggregates into chylomicrons? |
|
Definition
| Triglycerides, cholesterol, phospholipids, fat-soluble vitamins & newly formed lipoproteins |
|
|
Term
|
Definition
| Transport form for lipids in plasma |
|
|
Term
| How do chylomicrons leave the endothelial cell? What do they enter? |
|
Definition
| Exocytosis; Lymphatic System --> Circulation (plasma can turn milky) |
|
|
Term
| Hepatic (bile) & Pancreatic (lipase) disorders can lead to __________. |
|
Definition
| Maldigestion/Malabsorption of dietary fats |
|
|
Term
|
Definition
|
|
Term
| Every day, the equivalent of up to ____% of an animal's BW enter the GI as fluid, which has to be ____ to avoid ____. |
|
Definition
| 10%; Reabsorbed; Dehydration |
|
|
Term
| Massive amounts of water & electrolytes are _____ into the gut lumen via ______. |
|
Definition
| Actively Secreted; Saliva, Stomach juices, Intestinal Fluid, Pancreas & Bile juice |
|
|
Term
| The # of micromolecules _____ dramatically once hydrolysis of nutrients begins. |
|
Definition
|
|
Term
| Osmotic pressure of chyme ____ before absorption & water is ______ via _____. |
|
Definition
| Increases; Sucked into gut lumen; Osmotic Pull |
|
|
Term
|
Definition
| # of particles/V of sol'n |
|
|
Term
| As # of particles in V of sol'n increases, osmotic P ____. |
|
Definition
|
|
Term
| Water always follows ______ & its absorption entirely d/o absorption of _______ & _______. |
|
Definition
| Osmotic Gradients; Electrolytes & Nutrients |
|
|
Term
| What is the driving force for absorption of Glc, Gal, Na, Small peptides, aa's & Cl-? |
|
Definition
|
|
Term
| During absorption, accumulation of electrolytes & nutrients intracellularly & then in the lateral spaces before being transported off via blood creates steep _______ --> ______ follows ______ = is ______. |
|
Definition
| Osmotic Gradients; Water, Passively; Reabsorbed |
|
|
Term
| When more Na is absorbed, more _____ is reabsorbed. |
|
Definition
|
|
Term
| By the time chyme leaves SI, how much of its water content has been reabsorbed? |
|
Definition
|
|
Term
| Large amounts of bicarb are secreted into the gut lumen via ________ & must be recovered to _______. |
|
Definition
| Saliva, Pancreas, Bile, Intestinal Fluid, Mucus; Maintain pH neutrality |
|
|
Term
| What does recovery of bicarb d/o? What is it achieved by? |
|
Definition
| Sodium gradients; Absorption of CO2 |
|
|
Term
|
Definition
| Passively along its chemical gradient |
|
|
Term
| Is it more essential to reabsorb water or bicarb? |
|
Definition
|
|
Term
| What type of diarrhea do laxatives create? |
|
Definition
|
|
Term
|
Definition
| Softer than normal feces caused by an imbalance btw water absorption & secretion, leading to loss of body water, electrolytes, & bicarb via feces |
|
|
Term
| What is another name for osmotic diarrhea? |
|
Definition
|
|
Term
| If gut contains a lg # of mol's which are poorly or not absorbed --> _______ --> ______ |
|
Definition
| High osmolality of chyme --> Water is sucked into lumen |
|
|
Term
| What causes osmotic diarrhea? |
|
Definition
| Intake of non- or low absorbable compounds; Accumulation of partially digested ingesta; Loss of absorptive cells due to mucosal damage |
|
|
Term
| What are some non- or low absorbable compounds that can cause osmotic diarrhea? |
|
Definition
| Fructose, Sorbitol, Lactic acid, Laxatives |
|
|
Term
| What could cause accumulation of partially digested ingesta & osmotic diarrhea? |
|
Definition
|
|
Term
| What could cause loss of absorptive cells, resulting in incomplete digestion & malabsorption of micromol's? |
|
Definition
| Inflammations, Infections, Some Toxins |
|
|
Term
| What do toxins inhibit? Which one is kept in tact? |
|
Definition
| Many Na-cotransport mechanisms; Na-Glc |
|
|
Term
| What is secretory diarrhea? |
|
Definition
| Direct stimulation of secretory cells a/o mucus cells to secrete more fluid/mucus into gut lumen |
|
|
Term
| What are some causes of secretory diarrhea? |
|
Definition
| Some toxins; Mucosal irritants; Inflammatory mediators; Parasympathetic stimulation |
|
|
Term
| What are some toxins that cause secretory diarrhea? |
|
Definition
| E. coli toxin, Cholera toxin |
|
|
Term
| When are inflammatory mediators released that can cause secretory diarrhea? |
|
Definition
|
|
Term
| Describe what happens in secretory diarrhea. |
|
Definition
| More fluid is secreted than can be absorbed; Distension of GI wall; Stimulates Motility; Diarrhea |
|
|
Term
| Secretory diarrhea is more severe when ____ is present. |
|
Definition
|
|
Term
| What are the consequences of diarrhea? |
|
Definition
| Fluid loss; Bicarb loss; K+ loss; Epithelial defects/intestines |
|
|
Term
| What happens after fluid loss from diarrhea? |
|
Definition
| Hypovolemia; Hypoxia/Metabolic Acidosis/Tissue Damage + Shock & Circulatory collapse |
|
|
Term
| What happens after bicarb loss from diarrhea? |
|
Definition
| Loss of buffering capacity; Metabolic Acidosis; Tissue Damage |
|
|
Term
| What results from K+ loss from diarrhea? |
|
Definition
| Hypokalemia; Hyperpolarization of n/m membranes; Weakness & Hyporeflexia |
|
|
Term
| What results from epithelial defects/intestines from diarrhea? |
|
Definition
| Denuding of villi; Loss of barrier effect; Septicemia |
|
|
Term
| After K+ loss, are n. & m. cells more or less excitable? |
|
Definition
|
|
Term
| What is the most common cause of diarrhea? |
|
Definition
|
|
Term
| Where is enzymatic digestion & absorption of nutrients completed? |
|
Definition
|
|
Term
| The LI receive largely ____ material. |
|
Definition
|
|
Term
| What are some indigestible materials received by LI? |
|
Definition
| Structural carbs; Trapped nutrients like whole grain |
|
|
Term
| Which part of the GI displays large anatomical differences across spp? |
|
Definition
|
|
Term
| What are the 4 basic functions of LI in all spp? |
|
Definition
| Propulsion of chyme towards rectum; Absorption of remaining water & electrolytes; Microbial fermentation of undigested organic matter; Storage & expulsion of feces |
|
|
Term
| Do dogs have long or short LI? Horses? |
|
Definition
|
|
Term
| What does decreased blood glucose cause? |
|
Definition
|
|
Term
| At the end of ____ digestion, an animal will typically take in the next meal. |
|
Definition
|
|
Term
| Next meal --> _____ initiates _______ |
|
Definition
| Gastric Distension --> Gastro-Ileal Reflex |
|
|
Term
|
Definition
| Ileocecal Sphincter opens & ingesta is propelled into cecum |
|
|
Term
| Arrival of chyme in LI stimulates _____ |
|
Definition
|
|
Term
| When mechano- & chemoR's in the LI are stimulated, induces _______ |
|
Definition
| Increased motility to propel chyme towards rectum |
|
|
Term
| What is the LI motility pattern? |
|
Definition
| Mixing/Segmentation mvmts; Peristaltic & Antiperistaltic mvmts; Mass mvmts btw distal colon & rectum |
|
|
Term
| What is the purpose of mass mvmts btw distal colon & rectum? |
|
Definition
|
|
Term
| What induces mass mvmts in the LI? |
|
Definition
| Gastro-Colic & Duodeno-colic Reflex (Vagal); Irritation of Colon; Stimulation of PNS |
|
|
Term
| What animal has a lot of anti-peristaltic mvmts in the LI? |
|
Definition
|
|
Term
| Compared to SI, mucosa of LI is much ____ |
|
Definition
|
|
Term
| Does LI mucosa contain villi? C of L? |
|
Definition
|
|
Term
| Do absorptive cells of the LI express BBM enzymes? Transporters? |
|
Definition
|
|
Term
| Where are the secretory & mucus cells of the LI? |
|
Definition
|
|
Term
| What is fermented in the LI? By what? Into what? |
|
Definition
| Indigestible matter & "escaped" nutrients; Bacterial enzymes; VFA's, CO2, CH4 |
|
|
Term
| What type of pH does fermentation create? |
|
Definition
|
|
Term
| What is secreted in the LI? |
|
Definition
| Bicarb-rich fluid & mucus |
|
|
Term
| What is the purpose of the bicarb-rich fluid & mucus in the LI? |
|
Definition
| Buffering of fermentation products to protect mucosa |
|
|
Term
| What is osmotic water influx in the LI b/o? |
|
Definition
|
|
Term
| As fermentation increases, [VFA] _____ |
|
Definition
|
|
Term
| What is absorbed in the LI? |
|
Definition
| Sodium; Fermentation Products, Some vitamins produced by bacteria (K) |
|
|
Term
| How is sodium absorbed in the LI? What follows? |
|
Definition
| Active Na-K pump; Chloride & Water |
|
|
Term
| What regulates the Na-K pump in the LI? |
|
Definition
|
|
Term
| How are fermentation products absorbed? Followed by what? |
|
Definition
| Simple diffusion; Water (osmotically) |
|
|
Term
| What, in the LI, can lead to copious secretion of mucus & fluid --> diarrhea? |
|
Definition
| Intense irritation (colitis) or psychogenic tension (anxiety) |
|
|
Term
| What is 1 cause of colitis? |
|
Definition
|
|
Term
| Psychogenic Tension via ____ causes _____ |
|
Definition
| Limbic system; Parasympathetic stimulation |
|
|
Term
| When aldosterone increases, Na absorption ____. |
|
Definition
|
|
Term
| What reflexes are associated w/ defecation? |
|
Definition
| Myenteric & Parasympathetic (via pelvic nn.) |
|
|
Term
| What is the myenteric reflex of defecation? |
|
Definition
| Mass mvmts move feces from colon to rectum; stimulates pressure R's in rectum; stimulates myenteric plexus; Peristalsis & Internal sphincter relaxation --> Defecation |
|
|
Term
| The myenteric reflex is a ____ reflex, fortified by ___. |
|
Definition
| Weak; Parasympathetic Reflex |
|
|
Term
| What is the parasympathetic reflex of defecation? |
|
Definition
| Rectum distension --> Afferent parasymp. fibers --> spinal cord --> efferent parasy. fibers/pelvic nn. --> Intensified peristalsis |
|
|
Term
| What can block the defecation reflex? Via what nerve? |
|
Definition
| Voluntary constriction of external sphincter & puborectal mm. (via pudendal n.) |
|
|
Term
| Pelvic n. damage --> _____ --> _____ |
|
Definition
| Paralyses defecation reflex --> Constipation |
|
|
Term
| Pudendal n. damage --> _____ --> _____ |
|
Definition
| Abolishes control --> Fecal Incontinence |
|
|
Term
| Damage of what n. leads to constipation? |
|
Definition
|
|
Term
| Damage of what n. leads to fecal incontinence? |
|
Definition
|
|
Term
| Which of the defecation reflexes is more powerful? |
|
Definition
|
|
Term
| Is the external anal sphincter voluntary or involuntary? |
|
Definition
|
|
Term
| Is the inner anal sphincter voluntary or involuntary? |
|
Definition
|
|
Term
| Maldigestion/Malabsorption = _____ |
|
Definition
|
|
Term
| What, in evolutionary terms, is the most successful group of land mammals? |
|
Definition
|
|
Term
| What is the problem of land mammals? |
|
Definition
| The most abundant component of natural food resources, namely structural carbohydrates, can't be digested by any mammalian enzyme system |
|
|
Term
| What type of linkages do structural carbs have? |
|
Definition
|
|
Term
| What is the solution that ruminants developed for the problem of land mammals? |
|
Definition
| Symbiotic relationship w/ microbes, which are able to ferment structural carbs |
|
|
Term
| What are the compromises of ruminants? |
|
Definition
| Enormous fermentation chambers to gain sufficient energy out of a slow process; All ingested food 1st exposed to & shared w/ microbes (even if host could digest these nutrients itself) |
|
|
Term
| What does the ruminant's forestomach consist of? |
|
Definition
|
|
Term
| What part of the forestomach are pseudoruminants lacking? What is one pseudoruminant? |
|
Definition
|
|
Term
| Which part of the ruminant forestomach has a honeycomb-like appearance? |
|
Definition
|
|
Term
| What is the size of the reticulo-omasal orifice? |
|
Definition
|
|
Term
| What is the volume of the reticulorumen in cattle? |
|
Definition
|
|
Term
| What divides the reticulorumen into functional compartments? |
|
Definition
|
|
Term
| What is the reticulorumen covered w/? |
|
Definition
| Stratified Squamous Epithelium (Aglandular) |
|
|
Term
| The motility pattern of the reticulorumen is ____. |
|
Definition
|
|
Term
| Reticulorumen has complex motility pattern in order to... |
|
Definition
| Mix & retain ingesta to enable microbiotic activity; Enable release of gas; Coordinate regurgitation; Pass on fermented matter into omasum |
|
|
Term
| How long does full fermentation req? |
|
Definition
|
|
Term
| How much saliva do ruminants produce each day? |
|
Definition
|
|
Term
| What is stratification of ruminal ingesta b/o? |
|
Definition
| Density of food/Differences in gravity |
|
|
Term
| From top to bottom, what is the stratification of ruminal ingesta? |
|
Definition
| Gas Cap, Plant Mat (solid zone), Slurry zone, Potential escape zone, Liquid zone |
|
|
Term
| What is the solid zone of the ruminal ingesta? |
|
Definition
| D rumen receives undigested plant matter, ~1-2cm long, forming a mat of entangled fibers w/ air & gas trapped in btw (floating mat) |
|
|
Term
| What is the gas cap of the ruminal ingesta? |
|
Definition
| Microorganisms produce gas during fermentation, which floats to the top |
|
|
Term
| Which ruminal strata are plant fibers in? |
|
Definition
|
|
Term
| What is the liquid zone of the ruminal ingesta? |
|
Definition
| Mixing & fermentation break fibers up & small particles sediment into the liquid zone (saliva & water) |
|
|
Term
| Is liquid heavier or lighter than plant matter? |
|
Definition
|
|
Term
| What is the potential escape zone of the ruminal ingesta? |
|
Definition
| Only sufficiently fermented (small) particles & fluid move from here into the omasum |
|
|
Term
| What is the A cycle of rumination? |
|
Definition
| Primary Contraction/Mixing Cycle |
|
|
Term
| What is the 1st reticulorumen mvmt of the A cycle? |
|
Definition
| Biphasic contraction of reticulum; During 2nd contraction, omasal orifice dilates & omasum relaxes (suction) |
|
|
Term
| What is the 1st ingesta mvmt of the A cycle? |
|
Definition
| Coarse, light particles --> D sac; Smal, heavy particles + Fluid --> Cr Sac & Omasum |
|
|
Term
| What is the 2nd reticulorumen mvmt of the A cycle? |
|
Definition
| Reticulum relaxes; Cr sac contracts; Cr-Cd contraction of D sac & D blindsac |
|
|
Term
| What is the 2nd ingesta mvmt of the A cycle? |
|
Definition
| Fluid flows back into reticulum; Coarse, light particles mixed in D rumen; Small heavy particles + fluid pressed V'ly |
|
|
Term
| What is the 3rd reticulorumen mvmt of the A cycle? |
|
Definition
| Cr-Cd contraction of V sac & V blind sac followed by Cd-Cr moving contraction |
|
|
Term
| What is the 3rd ingesta mvmt of the A cycle? |
|
Definition
| Small particles & fluid pressed D & flow back into Cr sac/reticulum; Coarse fibers remain in D sac |
|
|
Term
| A cycles occur w/ a frequency of ______ d/o coarseness of diet. |
|
Definition
|
|
Term
| When are A cycles absent? |
|
Definition
|
|
Term
| What are the overall effects of the stratification & A cycle? |
|
Definition
| Freshly swallowed food is moved into rumen & added to floating mat; Floating mat compressed & mixed; Small fermented particles pressed out & sink into fluid; Small particles & fluid move via Cr sac back into reticulum & pass through omasal orifice w/ next reticular contraction |
|
|
Term
| In the A cycle, how are different passage rates achieved? |
|
Definition
| D/o digestibility (fermentability) of ingesta |
|
|
Term
| Are coarse fibers of low digestibility or easily fermented? Lush grass & concentrates? |
|
Definition
| Low digestibility; Easily fermentable |
|
|
Term
| How long are coarse fibers retained? |
|
Definition
|
|
Term
| What is the B cycle of rumination? |
|
Definition
| Secondary Contraction/Eructation contraction of the Reticulorumen & Ructus |
|
|
Term
|
Definition
|
|
Term
| Gases formed during fermentation (up to ____ in cattle per day) must be _____. |
|
Definition
|
|
Term
| What are the B cycle movements? |
|
Definition
|
|
Term
| The B cycle follows after how many A cycles? Depending on what? |
|
Definition
| 2-3; Rate of gas formation |
|
|
Term
|
Definition
| Cd-Cr contraction of rumen push gas cap fwd to cardia region; activates cardia R's; sphincter relaxation; gas enters esophagus; Antiperistaltic wave moves gas orally |
|
|
Term
|
Definition
| Lateral recumbency during anesthesia, obstruction of esophagus, ruminal stasis |
|
|
Term
| What does inhibition of ructus lead to? |
|
Definition
| Accumulation of gas; BLOAT; pressure on thoracic organs; Circulatory failure |
|
|
Term
| What reflex controls reticulorumen motility? |
|
Definition
|
|
Term
| What is involved in the vagal reflex of reticulorumen motility? |
|
Definition
| R's in mouth, forestomach, stomach, SI; Vagal afferent fibers; Motility center in MO; Vagal efferent fibers |
|
|
Term
| In reticulorumen motility vagal reflex, intrinsic system can ____ activity, but can't maintain ____. |
|
Definition
| Modulate; Coordinated motility pattern |
|
|
Term
| What are the main R's of the vagal reflex of reticulorumen motility? |
|
Definition
|
|
Term
| What stimulates stretch R's in the reticulorumen? |
|
Definition
| Mild to moderate distension of reticulorumen wall |
|
|
Term
| What do stretch R's of the reticulorumen do? What inhibits them? |
|
Definition
| Increase motility & rumination; Severe Distension |
|
|
Term
| What do chemoR's of the reticulorumen monitor? |
|
Definition
|
|
Term
| What is the normal pH range of the reticulorumen? |
|
Definition
|
|
Term
| What pH do chemoR's in the reticulorumen respond to? |
|
Definition
|
|
Term
| What do chemoR's of the reticulorumen do when pH falls <5? |
|
Definition
| Depress motility to slow down fermentation |
|
|
Term
| What pH is considered rumen acidosis? |
|
Definition
|
|
Term
| Does the motility center in ruminants show spontaneous activity? What is it driven by? |
|
Definition
| No; Excitatory signals from R's |
|
|
Term
| wrt the motility center in ruminants, what results from R damage or inhibition? |
|
Definition
| Ruminal Stasis (Vagal indigestion), e.g. TRP (Traumatic Reticuloperitonitis) |
|
|
Term
| Aside from pH <5, what can inhibit reticulorumen activity? |
|
Definition
|
|
Term
| What is ejection/rumination? What happens? |
|
Definition
| Remastication; An extra contraction of the reticulum, cardia relaxes, glottis closes, inspiration mvmt sucks bolus into esophagus, antiperistaltic wave propels bolus into mouth, water pressed out/swallowed; rechewing |
|
|
Term
| Ejection/rumination is a crucial part of a ruminant's digestion to: |
|
Definition
| Break up coarse fibers, increasing SA for microbes; Stimulate saliva secretion to stabilize rumen environment (buffers) |
|
|
Term
| In ruminants, periods of ____ alternate w/ periods of ___. ( ___ ) |
|
Definition
| Feeding; Rumination (Circadian Rhythm) |
|
|
Term
| Ejection/Rumination is a ______ reflex involving ________ stimulated by _______ which react to _____. |
|
Definition
| Complex Vagal Reflex; Rumination Center/MO; MechanoR's; Fiber coarseness & degree of filling |
|
|
Term
| When does ejection/rumination occur? |
|
Definition
| Immediately befoe an A-cycle |
|
|
Term
| What does rumination indicate? When is it disturbed? |
|
Definition
| Animal's well-being; Stress, Sickness, Pain |
|
|
Term
| A-cycle contractions involve what parts of the reticulorumen? |
|
Definition
|
|
Term
| B-cycle contractions involve what parts of the reticulorumen? |
|
Definition
|
|
Term
| What is the most important stimulus for salivation in ruminants? |
|
Definition
|
|
Term
| What does the host provide to microbes of the forestomach? |
|
Definition
| Shelter, Food, Water, Removes waste products, Maintains constant environmental conditions (temp, pH, osmolality, low O2) |
|
|
Term
| What do microbes provide to the host? |
|
Definition
| Energy through fermentation of otherwise undigestible food; Nutrients through synthesis (proteins, vitamins) |
|
|
Term
|
Definition
| Anaerobic metabolism (hydrolysis) of nutrients by microbes |
|
|
Term
| What is the forestomach ecosystem? |
|
Definition
| Symbiotic relationship btw host & microorganisms; Both partners benefit & would not survive w/o e/o |
|
|
Term
| Which part of the rumen's stomach is like the monogastric stomach? |
|
Definition
|
|
Term
| Does the stomach have a high or low accommodation capacity? The abomasum? |
|
Definition
|
|
Term
| What is the function of the omasum? |
|
Definition
| Passing on of fermented particles from reticulum to abomasum; Absorption of residual VFA, H2O & bicarb; Some grinding effect |
|
|
Term
| What allows some grinding effect of the omasum? |
|
Definition
| Partly cornified epithelium |
|
|
Term
| What does passing on of fermented particles from reticulum to abomasum d/o? What can impair this? |
|
Definition
| Correct stratification of food in reticulum; TRP |
|
|
Term
| How important is the omasum? |
|
Definition
| Not extremely (Pseudorum's don't have one) |
|
|
Term
| Describe motility of the omasum. |
|
Definition
| Ingesta passes through reticulo-omasal orifice during 2nd contraction of reticulum (pushing action) while omasum relaxes (sucking action); Fluid & small particles enter omasum; Orifice closes briefly, canal contracts pressing ingesta btw leaves; body contracts pressing ingesta fwd into abomasum (pumping action) |
|
|
Term
| What is the retention time in the omasum? |
|
Definition
|
|
Term
| What controls omasal motility? |
|
Definition
|
|
Term
| What are 3 ruminal microbes? |
|
Definition
| Bacteria, Protozoa, Fungi |
|
|
Term
| Which ruminal microbes are essential? Which are non-essential? |
|
Definition
| Bacteria; Protozoa & Fungi |
|
|
Term
| When do bacteria colonize the rumen? From what? |
|
Definition
| After birth; Environment, Food, Contact |
|
|
Term
| How many species of bacteria are ruminal microbes? |
|
Definition
|
|
Term
| Ruminal bacteria are mostly _____ |
|
Definition
|
|
Term
| How are ruminal bacteria grouped? (E.g.) |
|
Definition
| According to function (Cellulolytic, Amylolytic, Proteolytic, Methanogenic) |
|
|
Term
| How do ruminal bacterial groups differ? |
|
Definition
| Main substrate, growth rate, fermentation speed, pH sensitivity |
|
|
Term
| When do protozoa colonize the rumen? How? |
|
Definition
| After birth; Contact to other ruminants |
|
|
Term
| How much of the microbial biomass of the rumen do protozoa constitute? |
|
Definition
|
|
Term
| What do ruminal protozoa provide the host? |
|
Definition
|
|
Term
| What is the fermentation pattern of protozoa similar to? |
|
Definition
|
|
Term
|
Definition
| Anaerobic, metabolize wide range of carbs |
|
|
Term
| What are the major VFAs? What % does each represent? |
|
Definition
| Acetate (60-70%), Propionate (20-30%), Butyrate (10%) |
|
|
Term
| What type of microbes ferment starch? |
|
Definition
|
|
Term
| Is starch soluble or insoluble? |
|
Definition
|
|
Term
| Amylolytic, Cellulolytic, & Hemicellulolytic microbes convert soluble & structural carbs to _____. |
|
Definition
|
|
Term
| What microbes ferment structural carbs? What are 3 examples of such carbs? |
|
Definition
| Cellulolytic & Hemicellulolytic; Cellulose, Hemicellulose, Pectin |
|
|
Term
| Microbes must enter plant matter through ____ or ____ for fermentation to begin. |
|
Definition
|
|
Term
| What are microbial enzymes a part of? |
|
Definition
|
|
Term
| What is released when Fructose is converted to Pyruvate? |
|
Definition
|
|
Term
| What are some short chain fatty acids? |
|
Definition
| Valeric, Isovaleric, Isobutyric, Methylbutyric Acid |
|
|
Term
| What is pyruvate converted to? |
|
Definition
| Acetate, Propionate, Butyrate, Lactate |
|
|
Term
| What is lactate converted to? |
|
Definition
|
|
Term
| What is released when pyruvate is converted to acetate? |
|
Definition
|
|
Term
| What is NADH2 converted to when pyruvate is converted to either propionate or butyrate? |
|
Definition
|
|
Term
| How many C does acetate contain? |
|
Definition
|
|
Term
| Microbes are continually flushed into _____ |
|
Definition
|
|
Term
| Rum's d/o digesting microbes to cover their own ______ |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is NPN supply achieved by in rum's? |
|
Definition
| Dietary Supplementation; Rumino-Hepatic N recycling |
|
|
Term
| Urea is a waste product of _____, formed in the _____. |
|
Definition
|
|
Term
|
Definition
| Catabolism of endogenous aa's (m. tissue) & Ammonia absorption from the rumen |
|
|
Term
| What happens if ruminal [NH3] is low? |
|
Definition
| Urea is secreted directly or via saliva into rumen for bacterial growth |
|
|
Term
| What happens if ruminal [NH3] is high? |
|
Definition
| Urea is excreted via kidneys |
|
|
Term
| In ruminants, most dietary proteins are ____ by ____ into ____. |
|
Definition
| Fermented, Microbes; NH3 & VFAs |
|
|
Term
| For their own growth, microbes synthesize _____ |
|
Definition
|
|
Term
| What do microbes req for protein synthesis? |
|
Definition
| Carbon skeleton (VFA), N source, ATP |
|
|
Term
| What are some sources of N for microbial protein synthesis? |
|
Definition
| Ammonia from proteinolysis (very limited in natural diet); NPN |
|
|
Term
|
Definition
|
|
Term
| What is the bottleneck for microbial production of protein? |
|
Definition
|
|
Term
| How does absorption of VFAs occur? |
|
Definition
| As free acids (lipophilic); In ionized form |
|
|
Term
| What is req'd for absorption of VFAs as free acids? |
|
Definition
|
|
Term
| What is probably involved w/ absorption of VFAs in ionized form? |
|
Definition
|
|
Term
| What does the increase in VFAs during fermentation do to rumen pH? |
|
Definition
|
|
Term
| Because of acidification from fermentation, the rumen must be constantly ______ via _______ |
|
Definition
| Buffered; Flow of saliva & bicarb secretion via rumen wall |
|
|
Term
| Are soluble carbs (concentrates) fermented faster or slower than structural carbs? |
|
Definition
|
|
Term
| Compared to structural carbs, fermentation of soluble carbs releases (more/less) VFAs, (more/less) energy for host, (favorable/unfavorable) for production systems. |
|
Definition
|
|
Term
| What does rapid acid increase in the rumen challenge? |
|
Definition
| Buffering capacity; can suppress useful bacterial pop's (potentially harmful) |
|
|
Term
| Do concentrates stimulate chewing & remastication? |
|
Definition
|
|
Term
| Fermentation yields ____ via ____ p'way |
|
Definition
|
|
Term
| What is the main p'way of fermentation? |
|
Definition
|
|
Term
| What is ATP utilized to regenerate? Via what p'ways? |
|
Definition
| Reduced co-factors (NADH2--> NAD+) via propionate & butyrate to keep p'ways open |
|
|
Term
| What is a waste product of the acetate p'way? |
|
Definition
|
|
Term
| CO2 is partly reduced by _______ to ______. What is the purpose of this? |
|
Definition
| Methanogenic bacteria; CH4; Regeneration of more co-factors |
|
|
Term
| CH4 contains large amts of ______ (lost) |
|
Definition
|
|
Term
| What microbial waste products diffuse out into rumen fluid? |
|
Definition
| Acetic, Butyric, & Propionic Acid (or salts) |
|
|
Term
| What type of carbs can ruminants digest? |
|
Definition
|
|
Term
| Waste products of fermentation contain ____ for host. |
|
Definition
|
|
Term
| The rumen eventually digests _____, which are its main protein source. |
|
Definition
|
|
Term
| What is the major energy source for the ruminant host? How much of the host's energy req's do they cover? |
|
Definition
|
|
Term
| What does decreased chewing & rumination do to buffer flow? |
|
Definition
|
|
Term
| What is the cause of rumen acidosis? Examples? |
|
Definition
| Imbalance btw VFA prod & buffering capacity; Sudden ingestion of lg quantities of highly digestible carbs (grain engorgement) |
|
|
Term
| In rumen acidosis, VFA ____, Salivation/Rumination ____, pH _____. |
|
Definition
| Increases; Decreases; Decreases |
|
|
Term
| What can cause grain engorgement? |
|
Definition
| Breaking into a grain store; Concentrate diets, esp. before slaughter |
|
|
Term
| What pH is considered rumen acidosis? |
|
Definition
|
|
Term
| When rumen pH drops <5.5, VFAs shift from _____ to ____. (pka ___) |
|
Definition
| Ionic to free acid state (pka 4.8) |
|
|
Term
| VFAs in free acid state are (ease of absorption). |
|
Definition
| Readily absorbed (just req's a conc gradient) |
|
|
Term
| What is normal intracellular pH? |
|
Definition
|
|
Term
| VFAs in free acid state + IC pH 7 --> _____. |
|
Definition
| Dissociation of free acids to ionic form & H+ |
|
|
Term
| When free acids dissociate to ionic form & H+, what happens to the H+/Na+ exchanger? Intracellular pH? |
|
Definition
| Becomes overloaded; Drops |
|
|
Term
| What does drop in pH do to Na+/K+ pump? |
|
Definition
| Inhibits, leading to further accumulation of H+ & Na+ |
|
|
Term
| What does IC Na accumulation lead to? |
|
Definition
| Water influx into epithelial cells = swelling |
|
|
Term
| What do low pH & edema do to epithelial cells? |
|
Definition
| Damage --> Necrosis (Ruminitis) |
|
|
Term
| Low pH favors _____ & inhibits ____. |
|
Definition
| Lactate producers; Fermentation to VFA |
|
|
Term
| Lactic acid is (ease of absorption). --> _____ |
|
Definition
| Not absorbed easily; Strong acid, pH drops further, osmolality rises, water enters rumen |
|
|
Term
| What are the results of rumen acidosis? |
|
Definition
| Damaged epithelium, Barrier function & absorption impaired, Systemic inf's (Liver), Metabolic acidosis, Ruminal stasis, Dehydration, Renal failure, Shock, Death |
|
|
Term
| What is the main contributing factor to ruminal stasis? |
|
Definition
|
|
Term
| Acute ruminal acidosis --> _____ |
|
Definition
|
|
Term
| What is the solution for ruminal acidosis? |
|
Definition
| Pump out & replace reticulorumen fluid (Expensive & rarely done) |
|
|
Term
| What can cause chronic rumen acidosis? |
|
Definition
| Overfeeding of soluble carbs, e.g. dairy cows |
|
|
Term
| Describe chronic rumen acidosis. |
|
Definition
| Borderline acidotic; Cornification of epithelium & decreased absorption (parakeratosis); Liver abscesses |
|
|
Term
| What is the function of the hindgut? |
|
Definition
| Absorption of water & electrolytes; Fermentation (to various degrees in all mammals); Feces formation/storage |
|
|
Term
| What is the energy coverage through fermentation in rabbits? |
|
Definition
|
|
Term
| What is the energy coverage through fermentation in horses? |
|
Definition
|
|
Term
| What is the energy coverage through fermentation in pigs? |
|
Definition
|
|
Term
| What is the energy coverage through fermentation in dogs? |
|
Definition
|
|
Term
| What is the energy coverage through fermentation in humans? |
|
Definition
|
|
Term
| What animals are cecum fermenters? |
|
Definition
| Rabbit, Chinchilla, Guinea Pig, Koala |
|
|
Term
| What animals are colon fermenters? |
|
Definition
| Horse, Elephant, Rhinoceros, Pig, Some Primates |
|
|
Term
| HG fermenters are always a combination of ____ & ____. |
|
Definition
|
|
Term
| What animal is in btw cecum/colon fermentor? |
|
Definition
|
|
Term
| What is the most successful HG fermentor? |
|
Definition
|
|
Term
| As a general rule, HG fermentation is very similar to ________. |
|
Definition
|
|
Term
| How long is the horse cecum? |
|
Definition
|
|
Term
| What is the horse's cecum divided into? |
|
Definition
|
|
Term
| What does the cecum receive?(Horse) |
|
Definition
| Slurry-like ingesta from SI |
|
|
Term
| What is the function of the cecum?(Horse) |
|
Definition
| Mixing mvmt's btw haustra; Occasional mass mvmt's - apex & corpus contract, then base --> ingesta moves through cecocolic orifice into RVC |
|
|
Term
| What is the sequence of the VC?(Horse) |
|
Definition
| RVC, Sternal Flexure, LVC, Pelvic Flexure |
|
|
Term
| What type of segmentation does the VC have? What is its function?(Horse) |
|
Definition
| Haustric; Mixing, Peristalsis & Anti-Peristalsis originating from Pelvic Flexure --> Long retention of ingesta in VC |
|
|
Term
| Describe the Pelvic Flexure. What is its function?(Horse) |
|
Definition
| Marked reduction of diameter; Functions similar to pylorus; Helps to retain lg particles & pass on liquid & sm fermented particles |
|
|
Term
| What is the sequence of the DC?(Horse) |
|
Definition
| LDC, Diaphragmatic Flexure, RDC, junction to SC |
|
|
Term
| Describe the function of the DC. (Horse) |
|
Definition
| Mvmt's similar to VC w/ retention of ingesta @ junction |
|
|
Term
| What is the total retention time in the lg colon of horses? |
|
Definition
|
|
Term
| What is the total volume of the lg colon in horses? |
|
Definition
|
|
Term
| In the horse, where does most fermentation occur? |
|
Definition
|
|
Term
| What is the pacemaker area of the LC of the horse? |
|
Definition
|
|
Term
| What is the biggest difference of HG fermentation (compared to rumen)? |
|
Definition
| HG receives pre-digested mix of feeds, endogenous fluids & cells |
|
|
Term
| Describe digestion in the SI of the horse. |
|
Definition
| Not very efficient; Fast passage rate of ingesta; Pancreatic enzymes not very important; Even many soluble carbs reach LI & will be fermented |
|
|
Term
| What occurs in the HG during fermentation & absorption? (Different from rumen) |
|
Definition
| Large Water Mvmt's via osmosis & Cl-secretion from crypts |
|
|
Term
| What is the daily fluid volume entering/leaving HG? |
|
Definition
| = Total ECF volume of horse (20-25% BW) |
|
|
Term
| In the HG, how is buffering of VFAs achieved? |
|
Definition
| Mucosal secretion of HCO3- (ileum & HG secretion) |
|
|
Term
| What is the most favorable difference btw HG fermentation & ruminal fermentation? |
|
Definition
| Acetate instead of CH4 production (less energy loss): 4 H2 + 2CO2 --> CH3COOH + 2 H2O |
|
|
Term
| In HG fermentation, N recycling exists w/ _____ into cecum & colon. |
|
Definition
|
|
Term
| In HG fermetors, are microbial proteins & vit's (K & B complex) available to the host? |
|
Definition
|
|
Term
| What is done to make up for the deficiency of microbial proteins & vit's in Lagomorphs? |
|
Definition
|
|
Term
| What is another term for Coprophagia? |
|
Definition
|
|
Term
|
Definition
| Microbe-rich cecum content excreted once daily through rapid peristalsis --> Ingested --> Proteins & Vit's recovered via SI digestion/absorption |
|
|
Term
| Describe coprophagia in neonates. |
|
Definition
| Coprophagia from mothers --> access to microbes |
|
|
Term
| Horses are ____ grazers, giving them more access to ____ than cows, which are _____ grazers. |
|
Definition
|
|
Term
| HG fermentors are vulnerable to antibiotics, esp. _____ specific; _______ (killed intestinal flora) |
|
Definition
|
|
