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physiology
exam 2
| Question | Answer |
|---|---|
| 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
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