Physio 2 - Endocrinology 1

drraythe's version from 2015-06-09 01:45

General Endocrinology

Question Answer
what is anabolism?Anabolism is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy. (powered by catabolism)
what is catabolism?Catabolism is the set of metabolic pathways that breaks down molecules into smaller units to release energy.
What ARE hormones?they are chemical messengers
in what three ways are hormones physiological regulators of growth?Regulate metabolism, homeostasis, and reproduction
if produced in an endocrine gland, what are they called?glandular hormones
if produced in a endocrine gland CELL, what are they called?tissue hormones
what does paracrine mean?the hormones are secreted locally
what does endocrine mean?the hormones are secreted into the circulation
what do hormones affect? (general)TARGET cells/organs
describe concentrations of hormonesthey occur in VERY low concentrations
name the 6 main endocrine glandspituitary, thyroid/parathyroid, adrenal, pancreas, ovary, testes
name the main 7 endocrine tissuesCNS, C-cells(thyroid), thymus+immune system, lung, heart, kidney, GI
what are the 4 chemical classes of hormones, and what is their main properity?(1) peptide/protein hormones (hydrophilic) (2) steroid hormones (lipophilic) (3) amines (tyrosine (AA) derived-some lipo and some hydro) (4) eikosanoid hormones (hydrophilic)
where do most peptide hormones come from? (4)pancreatic, many hypothalamic, most pituitary, parathyroid hormone (ha...they all have the letter P in them)
where do most steroid hormones come from? (3)adrenal cortex hormones, repro hormones, D hormone (as in the vitamin) (Dz nuts get my adrenaline going! I'm on steroids! GRR!)
which amine hormones are lipophilic?thyroid hormones (thyroid can make you fat b/c greedy-its amine. lol)
which amine hormones are hydrophilic?dopamine, melatonin, epinepherine (that dope melon gets my epi up--i want it to be amine)
where do eikosanoid hormones come from? (where from what)Tissue hormones, all derived from arachidonic acid
what are the two eikosanoid hormones?prostaglandins and leukotrienes
how are protein hormones made?need STIM to an endocrine gland cell to initiate, larger pre-pro hormones are initially produced, then the pre-pro sequences are cleaved off leaving the actual hormone
what is a pre-pro-hormone?a protein hormone is first made into one of these, then the pre-pro is cleaved off to be left with protein hormone
where are protein hormones stored?in vesicles (secretory granule)
when is a protein hormone released from storage? and how?released from vesicle when theres a stim. Released via EXOCYTOSIS
**How fast are protein hormones produced? Released?Slowly produced (min 45 min) but quickly released (b/c stored, only 2-5min)
**are protein hormones hydrophilic or lipophilic? which means for xport?hydrophilic. dissolve in plasma to be xported
**describe the half-life of a protein hormoneshort half life (few min) because they are quickly destroyed by plasma/renal proteases
**what breaks down protein hormones?plasma/renal proteases
**what is good to know about the pre-pro sequences of the protein hormones?they can be active components too
what are steroid hormones derived from?cholesterol
**how fast are steroid hormones produced? Released?quickly for both
**where are steroid hormones stored?they aren't stored anywhere-- however, the plasma-protein bound steroid hormones can act like a reserve in plasma
**are steroid hormones hydrophilic or lipophilic? which means for xport?lipophilic, which means they need transport proteins in plasma
**how many steroid hormones are on average, free in plasma? which is active, bound or unbound to plasma protein?1-10% free on average. BOUND is inactive
**describe half-life of steroid hormonesprotein binding (b/c lipophilic) protects against quick destruction in liver, so theres a LONGER half life (hours to days)
**in the most basic way, how do hormones FIRST affect their target tissues?by forming a HORMONE-RECEPTOR complex, which alters the activity of the target cell
where are the receptors for hydrophilic hormones? why?on cell membrane, b/c they cant diffuse across membrane
where are the receptors for lipophilic hormones? why?cytoplasm or nucleus, b/c they CAN diffuse across membrane
describe the three main things about hormone receptors?they are LARGE protein molecules, they are HIGHLY SPECIFIC, and they have HIGH AFFINITY for their hormone
when does the hormone effect on the receptor stop? (3)(1) dissociation from receptor (2) after internalization of receptor-hormone complex (3) degradation
what is up/down regulation?when the number of receptors per target cell goes up or down
what is an agonist/antagonist?a SYNTHETIC HORMONE which binds to the same hormone receptor and either mimics the action or blocks the action of the hormone (respectively)
which lipophilic hormone binds to a cytoplasm receptor?steroid hormones (cytoplasm's doing steroids)
which lipophilic hormone binds to a nucleus receptor?thyroid hormones (thyroid makes you go deep--and can b/c its lipophilic)
when lipophilic hormones form the activated hormone-receptor complex, what happens next?the complex binds to a DNA acceptor site and initiates gene transcription= NEW PROTEINS SYNTHESIZED
**what do lipophilic hormones induce?PROTEIN SYNTH. most of the proteins are ENZYMES which then stim or inhibit metabolic pathways= METABOLIC EFFECT
**what type of effect do lipophilic hormones have?METABOLIC effect
example of a lipophilic hormone...what does aldosterone (steroid) do?initiates synth of ATPase(cause ATP-->ADP, release energy), which stims Na/K pumps (in general: plays central role in the reg of BP mainly by acting on the distal tubules+collecting ducts of the nephron, inc reabsorption of ions and water in the kidney, to cause the conservation of sodium, secretion of potassium, inc water retention, and inc BP)
why is there a delay in the effect of steroid hormones?initiation of protein synth --> actual production requires time
*What kind of receptor/reaction do protein hormones deal with?SECOND MESSENGER
*Explain the process of a PROTEIN HORMONE causing an affect (6)(1) protein hormone binds to its receptor site in its target cell membrane. (2) receptor now binds with another receptor subunit (G PROTEIN) and activates it (3) the activated G protein now activates a membrane-bound enzyme (eg adenyl cyclase) (4) adenyl cyclase converts ATP to cAMP. (5) cAMP activates protein kinase A, which phosphorylates other enzymes (6) phosphorylation leads to stim or inhibit of these enzymes
What is important to note about the protein hormone's position when it's exerting an effect?it remains outside of target cell and xmits message via cAMP (the second messenger)
what is the second messenger in the protein hormone sequence?cAMP
(protein hormone) what does the G protein activate?a membrane bound enzyme, esp. adenyl cyclase
(protein hormone) what does adenyl cyclase do?convert ATP to cyclic AMP
(protein hormone) what does cAMP do?activates protein kinase A which phosphorylates other enzymes, which stims or inhibits the enzymes phosphorylated
**What is the overall effect of protein hormonesthey lead to a chain rxn at the end of which enzymes (metabolic pathways) are either stimulated or inhibited
hormone effects are proportional to what?the hormones concentration
what are most hormone concentrations controlled by?a negative feedback loop (stim-->hormone production/secretion-->target cell response-->metabolic change-->reduction of original stim)

Endocrine pancreas

Question Answer
what is the part of the pancreas that is endocrine?islet of langerhans
what does the islet of langerhans consist of? (4)Alpha (A) cells, Beta (B) cells, Delta (D) cells, F or PP cells
What do Alpha (A) cells secrete?glucagon
what do Beta (B) cells secrete?insulin and amylin (Amy is so sweet)
what do Delta (D) cells secrete?somatostatin (growth hormone-inhibiting hormone (GHIH) )
what do F or PP cells secrete?pancreatic polypeptide
What type of hormone is insulin? is it produced fast or slow, is it released fast or slow, is it stored?protein hormone. It's SLOWLY produced and then stored in vesicles for a fast response
how does insulin circulate? What is its half life?it circulates freely (hydrophilic). it has a pretty short half life (6-10min)
where is insulin degraded?in the LIVER (and kidneys) (by proteases)
what is the secretion of insulin controlled by? (by (3) and any specific levels? )by blood glucose levels ( >100 stim release, <80/90 inhibits ). increased plasma AAs also mildly stim insulin release. GI hormones (esp GIP) also stim insulin release (warming up)
**box thing. What is insulin associated with? (what to do with energy, what kind of metabolic hormone? )energy abundance and storage of excess energy= anabolic hormone ("construct molecules from smaller units")
what is an insulin sensitive tissue? exceptions?a body cell with an insulin receptor. Exceptions are the GLUCOSE-DEPENDENT TISSUES (they don't need insulin to take up glucose b/c GLUTs on outside, so they are INSULIN INDEPENDENT TISSUES)
after insulin receptor binding in insulin-sensitive tissues what happens (in the cell) (2)(1) beta parts of the receptor become the activated tyrosine kinase (=second messenger) (2) GLUTs translocate from golgi to CELL MEMBRANE (glc uptake occurs)
what does the activated tyrosine kinase do? (what is this tk from)when insulin is bound to receptor tk is activated (It is a SECOND MESSENGER), it then phosphorylates many enzymes (inhibition or stim of of certain metabolic paths)
how does insulin affect protein metabolism? (3)(1) inc AA uptake (2) inc prot synth (3) dec proteolysis
who does insulin affect carb metabolism?* (excess glc situation) (4)(1) inc glc uptake (2) inc glycolysis (making ATP with it) (3) inc glycogenesis (4) dec gluconeogenesis
how does insulin affect lipid metabolism? (3)(1) inc lipid uptake/storage (2) inc lipogenesis (3) dec lipolysis
*the 4 major things that happen from insulin release in the body? (not just sugar stuff)(1) glc made avail for all tissues for energy (2) blood glc declines (3) excess glc channeled into storage (glycogen, fat) (4) protein synth (growth) is stim
what kind of hormone is glucagon? (so how fast is it made/released/is it stored?) what is its half life?peptide hormone (protein) so made slow, stored, and released fast. Half life is apprx 5 min.
from what is glucagon secreted?pancreatic alpha cells AND the stomach (gut glucagon)
**what is the important box thing of glucagon?it opposes the insulin effects on carb metabolism in the LIVER
**what does glucagon stim in the liver? (2)(1) stim hepatic glycogenolysis (blood glc can double w/in minutes) (2) stim of hepatic gluconeogenesis (via AA uptake)
**Box thing for glucagon, it does what? (to blood glc levels)it INCREASES blood glucose level
what can glucagon do to adipose? when?in v HIGH conc, stim lipolysis
**box thing. what is the main signal for glucagon release? what inhibits it?HYPOGLYCEMIA stims release. It is inhibited by high plasma glucose levels
**box thing. what pancreatic cells are insulin-sensitive, and what is the effect?ALPHA CELLS (secrete glucagon) are insulin sensitive. so a high plasma glc --> high insulin --> glc uptake into alpha cells --> glucagon secretion inhibited
how is glucagon related to blood AAs?high plasma AA CAN stim glucagon release, but only when blood glc levels are LOW (AA then channeled into gluconeogenesis)

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