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phys - endocrine

endocrine system

Autocrine hormones act on the SAME/OTHER cells that produce them. same
Paracine hormones act on the SAME/OTHER cells that produce them. other
Neurotransmitters are released from presynaptic axon
3 characteristics of neurotransmitters 1.act rapidly 2.over short distances3.short duration
endocrine hormones are released by __________ into the ___________ and influence cells at a different location. specialized glands or cells circulation
3 characteristics of endocrine hormones 1. act slowly 2. act over long distances3. long duration
A hormone is a chemical that is secreted by . a cell or group of cells . into the blood for transport . has a distant target where it exerts its effect . in low concentrations
hormones are usually secreted by endocrine glands
other molecules that can act as hormones are secreted by 1. isolated endocrine cells within tissues 2. neurons 3. immune system cells
low amounts of hormones are OK because hormones have a high affinity (low Km) for their receptors
hormones bind to __________ and initiate a __________ receptors response
3 general classes of hormones Proteins and Polypeptides Steroids Tyrosine derivatives
Most abundant type of hormone in body Proteins and Polypeptides
Steroid hormones secreted by adrenal cortex, ovaries & testes, placenta
Steroid hormones cortisol, aldosterone, androgens & estrogens, vit D
Tyrosine derived hormones are secreted by thyroid, adrenal medulla
Tyrosine derived hormones Epi, NE thyroxine
peptide hormone size 100 aa
Peptide hormones synthesized on ___________ as ___________then cleaved to ___________ by peptidase in the ___ polysomes, prehormones, prohormones, ER
After being synthesized peptide hormones are transferred to the __________ for packaging into secretory vesicles Golgi
___________ in vesicles cleave prohormones into _____________hormones enzymes, active
vesicles release their contents into extracellular space or bloodstream via Ca2+ dependent exocytosis
Protein hormone secretion is RAPID/SLOW rapid (sec-min)
peptides are ________ soluble H2O
peptides have a LONG/SHORT half life short
peptides are lipo PHILIC/PHOBIC and CAN/CANNOT pass through the cell membrane (receptor cell) phobic, cannot
peptide hormones act on cells through membrane surface receptors
peptides hormones act on cells by initiating a second messenger system
2nd messenger systems have a RAPID response because they modify existing proteins
2nd messenger systems G protein coupled receptorsenzyme linked receptors
Steroid hormones are synthesized from ___________ and STORED/NOT STORED cholesterol, not stored
Steroid hormones are secreted SLOWER/FASTER than protein hormones Slower - they have to be synth from cholesterol
steriod synthesis occurs on the smooth ER
most cholesterol comes from plasma lipoproteins
T/F cholesterol can be made de novo TRUE
steroid hormones are lipo PHILIC/PHOBIC and CAN/CANNOT be stored philic, cannot
steroid hormones are released from the cell by diffusion - lipoPHILIC
steroid hormones are SOLUBLE/NOT SOLUBLE in body fluids not soluble
steroid hormones must be carried by ___________through the blood protein carrier molecules
steroid hormones bound to carriers are protected from proteases not active
in order for a steroid hormone to be active it must be BOUND/FREE from the carrier protein free
how does a steroid hormone cause an effect in the target cell diffuses thru membrane and binds a receptor in the cytoplasm, receptor-hormone goes to nucleus and activates transcription of certain genes
Tyrosine derived hormones act like peptide hormones bind membrane receptors - epi, NE, Dopa
Tyrosine derived hormones act like steroid hormones bind intracellular receptors - thyroid h
thyroid hormones increase _____________ in the _______________of a cell transcription, nucleus
factors that increase or decrease the amt of hormone in the blood rate of secretion rate of clearnace
hormones are cleared from the blood by metabolic destruction by tissues binding target tissues excretion by liver in bile excretion by kidney in urine
2 organs that aid in hormone excretion liver, kidney
down regulation of hormone receptors decreases responsiveness
upregulation of hormone receptors increases responsiveness
factors causing downregulation of hormone receptors inactivation of receptors inactivation of 2nd msgr proteins temp sequestration of receptors in cell destruction of receptors by lysosomes decreased production of receptors
hormone secretion stimuli external circadian rhythms spontaneous sleep
negative feedback turns DOWN or OFF!more important in maintaining homeoprevents oversecretion prevents overactivity of target tissue
positive feedback turns ON or UP!
part of brain involved in hormone production hypothalamus
hypothalamus is connected to _____________ by the ____________ pituitary, infundibulum
pituitary is under control of the hypothalamus
anterior pituitary hormones are controlled by _______________ & ______________ from the hypothalamus hypothalmic releasing and inhibiting hormones
hormone secretion from the posterior pituitary is controlled by __________________ that originate in the ______________ and end in the post pituitary nerve signals, hypothalamus
post pituitary hormones (from hypothtalmus) ADH Oxytocin
ant pituitary hormones transported from hypothtalamus to ant pit thru hypothalamic-hypophysial portal vessels
hypothalamus hormones acting on ant pituitary TRH-thyrotropin releasing hormone CRH-corticotropin releasing hormone GHRH- growth hormone releasing hormone GHIH- growth hormone Inhibiting hormone GnRH- gonadotropin releasing hormone PIH- prolactin inhib hormone
ant pituitary hormones GH - growth TSH - thyroid stim ACTH - AdrenoCorticoTropin LH - leutinizing FSH - follicle stim PRL - prolactin
principle endo areas pineal, parathyroidthyroid, thymus, pancreas, adrenal stomach, sm. intestine, ovary / testes
hormones prod by thyroid thyroxine-T4, triiodothyronine-T3, calcitonin
hormones prod by adrenal cortex cortisol, aldosterone, androgens & estrogens
hormones prod by adrenal medulla Epi NE
hormones prod by GI gastrin, secretin, CCK, GIP, motilin
hormones prod by brain melatonin, MSH-melanocyte stim
hormones prod by gonads testosterone, DHT, estrogen, progesterone
hormones prod bypancreas insulin, glucagon, somatostatin
hormones prod by parathyroid PTH - parathyroid
hormones prod by kidney renin, erythropoetin
hormones prod by liver angiotensin
hormones prod by heart ANP - atrial natriuretic
hormones prod by SKIN, LIVER, KIDNEY Vit D (calcitriol)
synergism combined effect is greater than either of them individually - more than additive
permissiveness hormone A needs hormone B present to work properly
antagonistic hormones work against each other
hypersecretion adenomas or cancerous tumors of glands
hyposecretion anywhere in feedback pathway
2nd msgr problems tissues not responding to circulatins hormone levels
primary hypersecretion is due to problem at primary organ or gland
secondary hypersecretion is due to problem at pituitary or hypothalamus
vasopressin ADH
ADH and Oxytocin are produced in the hypothalamus as prohormones packaged with convertases in vesicles, cleaved by convertases while traveling down axon to be released
ADH and Oxytocin are stored in ________ and exit the post pit. thru ________ vesicles, exocytosis
ADH is important in ______ regulation in the ___________ via the V2 receptor H2O, renal tubules
ADH plays a role in _________ regulation via the V1 receptor blood pressure
ECF osmolarity has what effect on ADH INCREASES ADH - increases H2O reabsorption - decreases ECF Os.
Oxytocin is very important during __________ and uses a POS/NEG feedback loop partruition, pos
positive feedback on oxytocin is caused by _____________ stimulis of the cervix stretch
__________ of cervix stops positive feedback of oxytocin relaxation (baby is now out)
oxytocin stimulates ______________ due to a nervous stimuli from breast milk let down
T/F each ant pit hormone has a specific target tissue true
hierarchical control multiple points of hormonal control
simple feedback control one point of control
prolactin action stim prod of milk proteins, stim add mammary growth, promotes vit prod (liver), inhibits LH and FSH secretion (GnRH suppression)
prolactin secretion stim by suckling
"normal growth" depends on GH and other hormonesadequate diet, absence of chronic stress, genetics
GH is produced by the anterior pituitary
GH exerts effectsA. on specific target tissues B. on all or almost all tissues in the body B. all or almost all tissues in the body
GH causes growth by increased cell size, increased mitosis, increased # of cells, specific differentiation
GH is released from cells called somatotrophs (GH=somatotrophin)
GH metabolic effects increased rate of protein synthesis, increased mobilization of FA's (use for E), decreased rate of glucose utilization BOTTOM LINE: enhance protein prod, reduce fat stores, conserves carbs.
GH via IGF-1 effects increases skeletal growth, strongly stim osteoblasts
GH needs ________ & __________ to work insulin and carbs
Somatomedins function indirectly mediate GH actions
Stimulation of GH secretion decreased blood glucose, decreased free blood FA's, starvation - fasting, protein deficient, trauma, stress, excitement, exercise, testosterone, estrogen, DEEP sleep, GHRH - stim
Inhibition of GH secretion increased blood glucose, increased free blood FA's, , aging, obesity, GHRH - inhib, growth hormone (exogenous), somatomedins
GH and IGF-1 feedback on the _____________ or _____________ anterior pituitary, hypothalamus
GH is primarily released _______________ in the sleep cycle
GH is also released during exercise
GH has a direct effect on which organs and tissues adipose, liver, muscle
GH has an indirect effect, thru IGF's which are produced in the _________ and have effect on which tissues liver;kidney, pancreas, intestine, islet cells, parathyroids, skin, connective tissue, bone heart, lung, chondrocytes, muscles(slide 67)
GH deficiency can cause . dwarfism(pre puberty), panhypopituitarism - inadeq secretion from ant pit, rate of dev decreased, decreased capacity to make cartilage and long bone, Laron dwarfism: GH hi, IGF-1 low receptor insensitivity
GH deficiency is treated with Human growth hormone (exogenous)
GH excessive caused by Pituitary adenoma
excessive GH causes Gigantism: adol onset, inc bone length & thickness, Acromegaly:adult onset, inc bone thickness, (nose, head, hands, feet), oragnomegaly. Pituitary diabetes:excessive insulin stim causes insulin insensitivity in tissues
Pituitary diabetes is caused by excess _____ and entails GH.TYPE II: overstim of insulin causes "insulin insensitive" tissues and dec glucose uptake, TYPE I: "burnout" of pancreatic B-islet cells
Created by: hollymtngirl

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