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physiology

exam 2

QuestionAnswer
what is the goal of the endocine system/ what does it work to maintain homeostasis
hormone syn in and secreted by glands
Common characteristics of endocrine cells and neurons 1. secrete substances into blood 2.some molecules are both NT and hormones 3. mechanism of action requires specific receptor 4. similar process of exocytosis of granules and synaptic vesicles 5. both systems may respond to the same stimuli
What are the 3 mechanisms used to restore and maintain homeostasis 1. receptor 2. control center 3. effector
receptor receives information of change occurance
control emmigration center. receives information and processes
effector responds to commands. either oppose or enhance stimulus.
Does restoring and maintaining homeostasis use positive or negative feedback loops? negative feed back loops
what do positive feedback loops result in for homeostasis amplifies change in specific condition. ex blood clotting and parturition
Ex pathways that alter homeostasis nutrition, toxins, psychological, physical, genetic, medical
Telecrine (endocrine) Travels long distances in blood
Neurocrine secreted by neuron
Autocrine hormone released from cell and act on itself or cells that are next to it . No blood travel
Paracrine close target cells. goes through interstitial fluid. No blood travel.
What are the main hormone classification types 1. peptides and proteins 2. steroids 3. amines 4. eixosanoids
Peptides and proteins AA building block. slight variation in structure across sp. Allows similar hormones to act on multiple receptors
Steroids syn from cholesterol. conserved structure amongst sp.
Amines syn from tyrosine
eicosanoids syn from FA
ex of peptides and proteins insulin, growth factors, GH, PTH, TH, TSH, antidiuretic hormone
catecholamines syn very fast release. syn with tyrosine. ex: epi, nor epi, dopamine
Thyroid hormone syn syn from tyrosine and iodide. storage in follicle (thyrogloulin)
steroid hormone syn from cholesterol. aren't stores, make new each time. ex: cortisol, aldosterone, androgen, estrogen, vit D
prostaglandins syn from arachidonic acid. typically have paracrine action
Neural hormone regulation mechanisms less common. stim of preganglionic nerve causes release of catecholamine from adrenal medulla. ex nor epi or epi
feedback mechanisms of hormone regulation more common. Long, short, ultra short. maintain homeostasis
what does the final outcome of interaction of hormone and target cell depend on 1. [H] 2. receptor # 3. affinity of hormone for receptor 4. duration of exposure to hormone 5. intracellular factor ex: enzymes and cofactor
how is hormone action expressed with a dose response curve
what does a dose response curve show the magnitude of response correlated with hormone concentration.
hormone sensitivity concentration of hormone producing 50% of maximal response
hormone sensitivity changes in what ways 1. changing number of receptors 2. affinity of receptors
decreasing sensitivity 1. decrease syn of new receptors 2. increased degradation of new receptors 3. inactivate receptors
increasing sensitivity 1. increase syn of new receptors 2. decrease degradation of new receptors 3. activate receptors
classic cell mem receptor systems classified according to membrane receptor structure or second messenger system. rapid response
catalytic cell mem receptor system No second messenger. uses enzyme (kinases). rapid response
intracellular receptor system steroid hormones. use cytoplasmic or nuclear receptors. slow response
classic cell mem receptor systems type 1. G proteins
G protein is active when GTP is bound
G protein is inactive when GDP is bound
G protein cell mem receptor can stim or inhibit
G proteins are link to what second messenger systems 1. Adenylyl cyclase 2. Phospholipase C
Adenylyl cyclase is link what what second messenger cAMP
Phospholipase C is link to what second messenger IP3/ Ca2+
What shuts down the adenylyl cyclase system when Phosphodiesterase degrades cAMP
Hormones using adanyly cylcase system CRH/ACTH, FSH/LH, TSH, ADH, Calcitonin, PTH, glucagon
Hormones using phospholipase C system GnRH, TRH, Angiotensin II, ADH, oxytocin
Catalytic receptors system types 1. Guanylyl cyclase enzyme 2. serine/threonine kinase enzymes
Atrial natriuretic peptide and No use what enzyme system Guanylyl cyclase
hormones that use intracellular receptor systems glucocorticoids, sex hormones, aldosterone, vit D, thyroid hormone
hypothalamic pit unit regulates functions of thyroid, adrenal, repro glands. controls growth, milk prod/ ejection, osmoreg
Posterior pit contains neurons descending from hypothalamus . secreted into capillary bed to rest of body
anterior pit hypothalamic releasing and inhibiting hormones ori from terminal axons in median eminence. hypothysial portal systems
TRH stims TSH and PRL
GnRH stims LH and FSH
CRH stims ACTH
GHRH stims GH
Somatostatin inhibits GH and PRL
PRF stims PRL
Dopamine inhibits PRL and ACTH
Dopamine stims GH
TSH stimulators TRH. decrease in T3 and T4
TSH inhibitors Dopamine, Somatostatin. increase in T3 and T4
what is ACTH initially secreted as POMC
ACTH stimulators CRH, decrease cortisol, ADH, stress
ACTH inhibitors Increase cortisol, ACTH, somatostatin, dopamine
LH and FSH stimulators GnRH, Activin, Pheromones
LH and FSH inhibitors Testosterone, estrogen, inhibin, melatonin
PRL stimulators TRH, estrogen, suckling, PRF
PRL inhibitors Dopamine, somatostatin, PRL
GH stimulators GHRH, decrease in glucose/FFA, increase in AA, hypoglycemia/fasting/starvation, estrogen, testosterone
GH inhibitors somatostatin, increase glucose/FFA, GH, obesity, somatomedins
somatomedins made in liver. IGF1 and IGF2
GH direct anabolic actions increase Ca absorption from gut, P reabsorption from kidney, protein syn in liver
GH indirect anabolic actions somatomedins. increase lean muscle mass, linear bone growth, organ size/function
GH direct catabolic effect increase gluconeogenesis (maintain BG), increase lipolysis (release FFA)
ADH syn by neurons in supraoptic nuclei of hypothalamus. work to retain and reabsorb water
ADH peptide precursor prepropressophysin
Oxytocin syn primarily by neurons in paraventricular nuclei of hypothalamus
Oxytocin peptide precursor preprooxyphysin
prepropressophysin componens ADH+Neurophysin2+signal peptide
preprooxyphysin components Oxytocin+neurophysin1+signal peptide
How is the signal peptide removed in ADH and oxytocin by golgi. then packed into pro hormone vessicles. vessicles then released in posterior pit.
ADH stimulators increased plasma osmolarity, decreased BV, decrease BP, pain, nausea, hypoglycemia, micotine/opiates
ADH inhibitors decreased plasma osmolarity, increased BV and BP, ethanol, glucocorticoids
Where can water be reabsorbed under the influence of ADH the distal convoluted tubule and collecting duct
ADH in kidney free water absorption. increase water permeability of principal cells in distal convoluted tubules and collecting ducts
ADH receptor V2. Aquaporin 2 is inserted into membrane of principal cells
Vascular smooth muscle contraction receptor V1. constricts arterioles
central diabetes insipidus lack of ADH secretion. circulating ADH is low. urine not concentrated b/c all water goes out in urine. large volume of dilute urine. High plasma osmolarity.
Peripheral or nephrogenic diabetes insipidus posterior pit normal but principal cells in collecting duct unresponsive to ADH. Normal or elevated ADH. lower plasma osmolarity. small amount of dilute urine
syndrome of inappropriate ADH secrection excess ADH released from post pit. hypervolemia and hyponatremia. urine very concentrated.
long hypophysial portal vessels travel from median eminence to endocrine cells in AP.
Created by: ejohnson17