Term
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Definition
| a polypeptide/protein secreted by one cell cluster/organ which is then secreted into the bloodstream or bodily fluid and acts on a target tissue elsewhere in the body. |
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Term
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Definition
| a hormone which acts on the same organ that secretes it such as secretin, ACh, and CCK |
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Term
| what are some examples of general hormones? |
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Definition
| epinephrine, norepinephrine, growth hormone and thyroid hormone |
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Term
| what are the different medical methods for controlling hormones? |
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Definition
| blocking synthesis, blocking release, blocking receptors, inactivating the molecule, and blocking the overall effect |
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Term
| what is the role of the pineal gland? |
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Definition
| regulation of the circadian rhythm via integration of light input and modulation of the endocrine system |
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Term
| what is the role of the hypothalamus? |
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Definition
| receiving input from the cortex/autonomics in the brain and translating it to the pituitary |
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Term
| can ischemia affect hormone efficacy? |
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Definition
| yes - b/c hormones require blood for transport (both arterial and venous flow). |
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Term
| what stimuli lead to release of local hormones? |
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Definition
| nerve impulses, synaptic transmission, and pH changes |
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Term
| what are examples of general hormone effects? |
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Definition
| fight/flight, increased/decreased metabolic rate, and disproportionate growth |
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Term
| how does the endocrine work with the CNS? |
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Definition
| they work together to stimulate a response, then shut it down via feedback mechanism |
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Term
| what is another name for the pituitary? |
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Definition
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Term
| what do the parathyroid glands deal with? |
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Definition
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Term
| why do you need to taper pts off steroids such as cortisol? |
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Definition
| exogenous administration can lead to negative feedback of endogenous production |
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Term
| how does the heart function as a endocrine organ? |
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Definition
| if the heart is not getting enough volume, it can release beta natriuretic peptide which signals the kidney/adrenals to retain more water |
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Term
| why is the pituitary particularly vulnerable to inflammation? |
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Definition
| all of the nerves and arteries supplying it are inside the thin infundibular stalk (located behind the optic chiasm) - which if constricted by inflammation = problems w/hormone release. |
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Term
| what is the super optic nucleus? |
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Definition
| a structure in the brain located above the optic chiasm which produces impulses that travel down into the posterior pituitary |
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Term
| why does the pituitary require a large venous plexus? |
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Definition
| in order to absorb hormones which are intended for release |
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Term
| why is the anatomical location of the pituitary so important? |
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Definition
| nasal infections may affect it easily (if sphenoid sinus/sella turcica is compromised) or if the gland enlarges - the optic chiasm may be affected, causing vision disturbances |
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Term
| what does the anterior pituitary produce? (*test question*) |
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Definition
| growth hormone (GH), adrenocorticotropin (ACTH), thyroid hormone (TSH), follicle stimulating hormone (FSH), luteinizing hormone (LH), and prolactin |
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Term
| what does the posterior pituitary produce? (*test question*) |
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Definition
| antidiuretic hormone (ADH/vasopressin) and oxytocin |
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Term
| what characterizes the adrenal gland's role in the endocrine system? |
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Definition
| ACTH from the anterior pituitary comes down and stimulates production of cortisol and androgens (from cholesterol). aldosterone is also produced in the adrenals (zona glomerulosa) which enhances Na+ reabsorption in the kidneys (increases water levels). |
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Term
| what characterizes the role of the thyroid gland in the endocrine system? |
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Definition
| the thyroid produces thyroxine (T4 - becomes triiodothyronine/T3 in periphery) which affects vasometabolic rates, potentiates reproduction, and potentiates other organ systems etc in response to TSH. tyrosine/iodine are necessary substrates for thyroid production. |
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Term
| what characterizes the pancreas as an endocrine organ? |
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Definition
| the pancreas produces insulin via its beta cells (decreases blood sugar levels) and glucagon via its alpha cells (increases blood sugar levels). |
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Term
| how does insulin decrease blood sugar levels? |
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Definition
| by increasing glucose transport into cells *along w/potassium* |
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Term
| what can occur with the pancreas if the exocrine portion of its function is blocked? |
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Definition
| pancreatic enzymes, including proteases/lipases can accumulate - leading to pancreatitis and autodigestion. HCO3- may also not be able to reach the duodenum and perform its protective function. if this occurs, Ca++ drops, WBCs increase, calcifications may be apparent on x-ray and the pts glucose/Na+ may be affected. |
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Term
| what do the parathyroids help regulate? |
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Definition
| parathyroid hormone increases Ca++ blood levels, which affects bone density and reabsorption of Ca++ by the kidney |
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Term
| how does the placenta function as an endocrine organ? |
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Definition
| the placenta produces hCG when its chorionic villi form as well as estrogen, progesterone, and human somatotropin (helps maintain the right water, electrolyte balance and growth and fetal food in the form of glucose). |
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Term
| what are the three general classes of hormones? |
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Definition
| steroids (*cortisol, *aldosterone etc - from cholesterol nucleus), tyrosine derivatives (*thyroxine, *triiodothyronine, *epinephrine etc - why pts need all essential amino acids), and proteins/peptides (everything else) |
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Term
| how can certain antibx mess w/the endocrine system? |
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Definition
| some antibx have effects on human ribosomes, which are needed to make the proteins found in some hormones |
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Term
| what is the progression of protein derived hormone creation? |
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Definition
| protein derived prehormones become prohormones in the RER, which are then packaged in the golgi complex and sent to secretory vesicles until their release. |
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Term
| what is the progression of tyrosine derived hormone creation? |
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Definition
| tyrosine derived hormones are created via cytoplasmic synthesis involving enzymes - meaning temp, pH, and nutrient levels all affect their synthesis. |
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Term
| what level of quantity are hormones active in? |
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Definition
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Term
| what is the onset of action for hormones? |
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Definition
| seconds to days (may be related to negative feedback mechanism) |
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Term
| where do proteins, peptides, and catecholamines bind in their target tissue? how does this affect the time from binding to effect? |
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Definition
| on cell membrane receptors - which allows an immediate effect |
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Term
| where do steroids bind in their target tissue? how does this affect the time from binding to effect? |
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Definition
| steroids bind in the cellular cytoplasm, which means they will take longer to have an effect (likely a couple of hours) |
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Term
| where do thyroid hormones bind in their target tissue? how does this affect the time from binding to effect? |
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Definition
| thyroid hormones bind to chromosomes and associated proteins in the cell nucleus - meaning their effect may not be evident for days to weeks. |
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Term
| what is receptor up-regulation? down-regulation? |
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Definition
| up-regulation of cell membrane receptors for certain hormones/drugs can increase their effectiveness w/the same level of hormone/drug being released. down-regulation of these receptors will decrease the efficacy of certain hormones/drugs at the same level of release. |
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Term
| what are the MOAs generally attributed to hormones? |
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Definition
| changes in *membrane permeability (aldosterone in DCT), intracellular *enzyme activation (speed up normal reactions), and *gene activation (directly affect DNA expression) |
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Term
| what is the second messenger mechanism employed by many hormones? |
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Definition
| a mechanism where adenyl cyclase is stimulated to produce *cAMP which is then used to activate a *cascade reaction which leads to *amplification of the intended effect |
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Term
| what hormones use the secondary messenger mechanism? (*test question*) |
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Definition
| *ACTH (adrenocorticotropin), *TSH (thyroid stimulating hormone), *LH (luteinizing hormone), *FSH (follicle stimulating hormone, and *ADH (vasopressin). other hormones, not as likely to be on test, but which use the secondary messenger mechanism: PTH, glucagon, catecholamines, and secretin |
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Term
| what characterizes the action of calmodulin? |
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Definition
| calmodulin is the "other 2nd messenger", operating in a different pathway than cAMP via 4 Ca++ binding sites which when activated, lead to conformational steric effects. therefore, drugs used to bind Ca++ can have endocrine effects through this mechanism. |
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Term
| what is the overall path of steroid hormones? |
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Definition
| adrenal cortex -> target cell cytoplasm -> binds to receptor proteins -> hormone+protein diffuse/are transported to nucleus -> transcription is activated -> mRNA diffuses out to the cytoplasm to ribosomes for translation |
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Term
| how are hormone levels determined? |
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Definition
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Term
| what is the effect of pituitary tumors on vision? |
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Definition
| pituitary tumors may grow into the optic chiasm which may create a visual disturbance |
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Term
| what are some symptoms of damage to the pituitary stalk? |
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Definition
| somnolence, obesity/emaciation, diarrhea, loss of libido, loss of muscle mass, etc. |
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Term
| what are some indications of anterior pituitary pathology? |
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Definition
| wrinkles, myxedema facies, loss of hair, loss of sexual characteristics, low blood sugar, and fatigue |
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Term
| what are signs/symptoms of hypo and pan hypopituitarism? |
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Definition
| changes in skin color, adrenal insufficiency, hypotension, decreased libido, and diabetes (if pt has bizarre symptoms that don’t seem to make sense, we’re looking in the wrong place) |
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Term
| what is the effect of pituitary growth hormone? |
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Definition
| enhanced AA transport into cells, increased DNA transcription, increased RNA translation, *increased protein synthesis*, decreased catabolism of proteins/AA, decreased use of glucose for energy, enhancement of glycogen deposition, increased blood glucose/less cellular uptake, and increased secretion of insulin ("diabetogenic effect"). appropriate GH is necessary for growth and maintenance of muscle tissue and RBC production. |
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Term
| what are pituitary somatomedins? |
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Definition
| insulin-like growth hormones, the most important of which: somatomedin C/IGF-1. |
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Term
| what are stimuli for GH release? (*test question*) |
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Definition
| starvation, protein deficiency, hypoglycemia, low FFA in blood, exercise, excitement, trauma, and deep sleep. |
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Term
| what are abnormalities of GH secretion? |
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Definition
| dwarfism, levi-lorain dwarf, and incompatible hGH tx |
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Term
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Definition
| an acidophilic tumor in the pituitary *prior to puberty can lead to maximum growth of all tissue prior to puberty |
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Term
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Definition
| an acidophilic pituitary tissue post puberty = big face/hands |
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Term
| what is the effect of ADH? |
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Definition
| stimulation of thirst/reabsorption of water by the kidney. ADH comes from the posterior pituitary |
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Term
| what is the effect of oxytocin? |
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Definition
| stimulation of parturition and colostrum release from the breasts |
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