Term
| 4 things that make up the gastrointestinal tract (GI tract) |
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Definition
1. esophagus
2. stomach
3. small intestine
4. large intestine |
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Term
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Definition
| the portion of the GI tract running from the stomach to the anus |
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Term
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Definition
| the soupy mixture of food & secretions |
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Term
3 pairs of salivary glands
*where the first stages of digestion begin in the oral cavity with chewing & the secretion of saliva* |
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Definition
1. sublingual glands (under the tongue)
2. submandibular glands (under the mandible)
3. parotid glands (near the hinge of the jaw) |
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Term
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Definition
| the narrow tube that travels through the thorax to the abdomen that swallowed food passes through |
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Term
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Definition
| a baglike organ that can hold as much as 2 liters of food & fluid when fully expanded; lies just below the diaphragm; where the esophagus ends |
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Term
| 3 sections of the stomach |
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Definition
1. upper fundus
2. central body
3. lower antrum |
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Term
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Definition
| the opening between the stomach & the small intestine that is guarded by the pyloric valve |
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Term
| 3 sections of the small intestine |
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Definition
1. duodenum
2. jejunum
3. ileum |
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Term
| After digestion finishes in the small intestine & nearly all digested nutrients & secreted fluids have been absorbed, how much chime per day passes into the large intestine? |
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Definition
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Term
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Definition
| the proximal section of the large intestine where watery chime becomes semisolid feces as water & electrolytes are absorbed out of the chime & into the ECF |
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Term
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Definition
| the terminal section of the large intestine where feces are propelled into; has a defecation reflex triggered by distension of the rectal wall |
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Term
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Definition
| where feces leaves the GI tract via its external anal sphincter which is under voluntary control |
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Term
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Definition
| small fingerlike extensions in which the intestinal mucosa projects into the lumen |
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Term
| What is the difference between "gastric glands" & "crypts"? |
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Definition
gastric glands = invaginations in the stomach
crypts = invaginations in the small intestine |
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Term
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Definition
| secretory glands formed by the deepest invaginations that open into the lumen through ducts |
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Term
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Definition
1. an inner mucosa facing the lumen
2. submucosa
3. muscularis externa (layers of smooth muscle)
4. serosa (a covering of connective tissue) |
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Term
| 3 layers of the mucosa (inner lining of the GI tract) |
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Definition
1. mucosal epithelium (a single layer facing the lumen)
2. lamina propria (subepithelial connective tissue that holds the epithelium in place)
3. muscularis mucosae (a thin layer of smooth muscle) |
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Term
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Definition
| larger visible bumps in the mucosa formed from collections of lymphoid tissue adjoining the epithelium |
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Term
| What tissue is majorly made up of lymphoid aggregations such as Peyer's patches? |
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Definition
| gut-associated lymphoid tissue (GALT) |
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Term
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Definition
| the middle layer of the gut wall |
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Term
| What system is the submucosal plexus (part of the submucosa) a major nerve network for? |
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Definition
| the enteric nervous system |
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Term
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Definition
| the outer wall of the GI tract; consists of 2 layers of smooth muscle (and inner circular layer & an outer longitudinal layer) |
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Term
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Definition
| the second nerve network of the enteric nervous system; lies between the longitudinal & circular muscle layers of the muscularis externa |
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Term
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Definition
| the outer covering of the entire digestive tract; a connective tissue membrane that is a continuation of the peritoneal membrane that lines the abdominal cavity |
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Term
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Definition
| sheets of the peritoneum that holds the intestines in place so that they do not become tangles as they move |
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Term
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Definition
| the chemical & mechanical breakdown of foods into smaller units that can be taken across the intestinal epithelium into the body |
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Term
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Definition
| the movement of substances from the lumen of the GI tract to the ECF |
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Term
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Definition
| movement of material in the GI tract as a result of muscle contraction |
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Term
| 3 significant challenges faced by the digestive system |
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Definition
1. avoiding autodigetion
2. mass balance
3. defense |
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Term
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Definition
| glycoproteins that primarily make up the viscous secretion that is mucus |
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Term
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Definition
| contraction-relaxation cycles lasting only a few seconds; ex) in the posterior region of the stomach & in the small intestine |
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Term
| slow wave potentials (slow waves) |
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Definition
| cycles of depolarization & repolarization associated with cycles of smooth muscle contraction & relaxation |
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Term
| interstitial cells of Cajal (ICCs) |
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Definition
| a network of cells where slow waves originate |
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Term
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Definition
| a pattern that is a "housekeeping" function that sweeps food remnants & bacteria out of the upper GI tract & into the large intestine |
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Term
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Definition
| progressive waves of contraction that move from one section of the GI tract to the next |
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Term
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Definition
| a mass of food behind which circular muscles contract in peristalsis |
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Term
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Definition
| short segments of intestine alternately contract & relax |
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Term
| 5 features the ENS shares with the CNS |
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Definition
1. intrinsic neurons
2. neurotransmitters & neuromodulators
3. glial support cells
4. diffusion barrier
5. integrating center |
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Term
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Definition
| neurons that lie completely within the wall of the gut |
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Term
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Definition
| reflexes that originate within the enteric nervous system & are integrated there without outside input |
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Term
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Definition
| digestive reflexes integrated in the CNS regardless where they originate |
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Term
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Definition
| reflexes that originate in the brain |
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Term
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Definition
| the GI hormone that enhances satiety (the feeling that hunger has been satisfied) |
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Term
| 2 hormones in the gastrin family |
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Definition
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Term
| glucose-dependent insulinotropic peptide |
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Definition
| a hormone that stimulates insulin release in response to glucose in the intestinal lumen |
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Term
| What family is the hormone glucagon-like peptide-1 (GLP-1) in? |
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Definition
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Term
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Definition
| the feedforward response created by the long reflexes that begin in the brain |
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Term
| 4 important functions of saliva |
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Definition
1. soften & moisten food
2. digestion of starch
3. taste
4. defense |
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Term
| 3 parts of the mouth that contribute to the mastication of food to create a softened, moistened mass that can be easily swallowed |
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Definition
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Term
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Definition
| grape-like clusters of the secretory epithelium of salivary exocrine glands |
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Term
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Definition
| swallowing; a reflex action that pushes a bolus of food or liquid into the esophagus |
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Term
| What does the epiglottis do as the bolus moves down toward the esophagus? |
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Definition
| folds down to complete closure of the upper airway & prevent food & liquid from entering the airways |
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Term
| 3 general functions of the stomach |
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Definition
1. storage
2. digestion
3. defense |
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Term
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Definition
| a cephalic phase reflex that begins digestive activity in the stomach before food even arrives |
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Term
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Definition
| when food enters the stomach & stimuli in the gastric lumen initiates a series of short reflexes |
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Term
| Where do gastric glands lie? |
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Definition
| deep within the mucosal layer |
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Term
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Definition
| cells deep in the gastric glands that secrete the hormone gastrin into the blood |
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Term
| gastrin-releasing peptide |
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Definition
| an ENS neurotransmitter that mediates short reflexes |
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Term
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Definition
| cells deep in the gastric glands that secrete gastric acid into the lumen of the stomach |
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Term
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Definition
| carries out the initial digestion of proteins |
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Term
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Definition
| cells in the gastric glands that secrete pepsin as the inactive enzyme pepsinogen |
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Term
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Definition
| a paracrine signal secreted by enterochromaffin-like cells (ECL cells) in response to gastrin or ACh stimulation |
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Term
| When does the intestinal phase of digestion begin? |
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Definition
| once chime passes into the small intestine |
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Term
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Definition
| the surface of the intestinal epithelium; names because of the bristle-like appearance of the microvilli |
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Term
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Definition
| a nonenzymatic solution secreted from hepatocytes (liver cells) |
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Term
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Definition
1. bile salts (facilitate enzymatic fat digestion)
2. bile pigments (the waste products of hemoglobin degradation)
3. cholesterol (excreted in the feces) |
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Term
| What makes up bile salts which act as detergents to make fats soluble during digestion |
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Definition
| steroid bile acids combined with amino acids |
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Term
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Definition
| stores & concentrates the bile solution after it is secreted by hepatocytes & has travelled here via the hepatic ducts |
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Term
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Definition
| the duct through while the gallbladder sends bile into the duodenum via contractions during a meal that includes fats |
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Term
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Definition
| enzymes that remove two fatty acids from each triglyceride molecule & therefore carry out enzymatic fat digestion |
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Term
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Definition
| a protein co-factor secreted by the pancreas & is necessary for fat digestion |
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Term
| 5 things that form small disk-shaped micelles as enzymatic mechanical digestion proceeds |
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Definition
1. fatty acids
2. bile salts
3. mono- & diglycerides
4. phospholipids
5. cholesterol |
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Term
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Definition
| intestinal brush-border enzymes that break down maltose & other disaccharides |
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Term
| endopeptidases (proteases) |
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Definition
| attack peptide bonds in the interior of the amino acid chain & break a long peptide chain into smaller fragments |
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Term
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Definition
1. pepsin (secreted in the stomach)
2. trypsin (secreted by the pancreas)
3. chymotrypsin (secreted by the pancreas) |
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Term
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Definition
| release single amino acids from peptides by chopping them off the ends, one at a time |
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Term
| Why is vitamin B12 also known as cobalamin? |
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Definition
| it contains the element cobalt |
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Term
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Definition
| the epithelial cells on the luminal surface of the colon that absorb Na+ |
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