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91 Cards in this Set
- Front
- Back
Cell to cell communication, name 4 methods
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gap junctions
neurotransmitters paracrines hormones |
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gap junction
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join single unit smooth muscle, cardiac muscle, epithelial and other cells to each other. passes nutrients, electrolytes, and signaling molecules . goes through pores in membranes
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neurotransmitters
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released by neurons, diffuse accross narrow synaptic cleft, and bind to specific receptors on next cell
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paracrines
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secreted by one cell , diffuse to nearby cells in the same tissue, and stimulate physiology. aka local hormones.
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hormones
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chemical messengers that are transported by the bloodstream. stimulate physiological responses. targets can be far away. what determines whether or not a target is affected? RECEPTOR.
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difference between endocrine and exocrine glands
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exocrine glands secrete products by way of a duct onto epithelial surfaces. such as skin or mucosa of digestive tract. endocrine glands are ductless and release products into blood stream. endocrine glands have high density of capillaries with pores.
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name two glands that are both endocrine and exocrine, and why:
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liver: exocrine: bile into ducts that lead to small intestine. endocrine b/c blood clotting factors into blood.
testes: sperm into ducts (exo) but testosterone in blood (endo) |
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nervous vs. endocrine system
type of signal speed of response persistance of response adaptation area of response |
nervous is chemical and electrical, endocrine strictly chemical
nervous is rapid (ms), stops quickly, and rapidly adapts endocrine is variable but may take days, response can persist long after stim stops, and adapt is slow. nervous is local and specific, endocrine is far away, widespread |
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Name some chemicals that are both neurotransmitters and hormones
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norepinephrine
cholecystokinin oxytocin and catecholamines come from modified neurons called neuroendocrine cells systems have overlap: neurons trigger hormones, hormones stim or inhibit neurons |
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anatomy of hypothalamus
shaped like where is it regulates what who is target |
shaped like flattened funnel
forms floor and walls of third ventricle regulates feeding, **reproduction, fight, flight target is pituitary |
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anatomy of pituitary gland
where, how attached location 2 structures |
pituitary suspended from hypothalamus by infundibulum and housed in sella turica of sphenoid bone.
anterior and posterior |
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how does hypothalamus control pituitary, what is it connected by?
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hypothal connected to anterior pituitary by hypophyseal portal system, primary capillaries to secondary capillaries. hypothalamic hormones make anterior secrete its own hormones. hypothal connected to posterior pit by nerve tissue called hypothal- hypophyseal TRACT. hypothal hormones stored and released by posterior pit, not synthesized here.
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Hormones that regulate the anterior pituitary and that are made by the hypothalamus
1st 3: |
thyrotropin releasing hormone: makes anterior pit release thryoid stimulating hormone and prolactin
corticotropin-releasing hormone: promotes secretion of adrenocorticotropic hormone gonadotropin-releasing hormone: follicle stimulating hormone and luteinizing hormone |
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Hormones that regulate the anterior pituitary and that are made by the hypothalamus
2nd 3: |
growth hormone releasing hormone: growth hormone
prolactin inhibiting hormone: also known as dopamine. inhibits secretion of prolactin somatostatin: inhibits secretion of growth hormone and thyroid stim hormone. Widespread effects here. |
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hormones made by hypothalamus that are stored and released by posterior pituitary
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oxytocin
antidiuretic hormone oxytocin produced by paraventricular nuclei, antidiuretic produced by supraoptic nuclei |
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anterior pituitary hormones: synthesizes 6 of them: and then in turn what do these hormones target:
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follicle stimulating hormone: target ovaries and testes.
luteinizing hormone: thyroid stimulating hormone: thyroid adrenocorticotropic hormone: adrenal cortex prolactin growth hormone/somatotropin |
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what does posterior pituitary store and release
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antidiuretic hormone
oxytocin |
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follicle stimulating hormone
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produced by anterior pituitary when hypothalamus releases gonadotropin-releasing hormone. In the ovaries, it causes growht of ovarian follicles and release of estrogen. In males, it causes sperm production.
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luteinizing hormone
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produced by anterior pituitary when hypothalamus releases gonadotropin-releasing hormone. It causes ovaries to undergo ovulation (release of egg), stimulates the corpus luteum to secrete progesterone (important for pregnancy). In males, makes testes secrete testosterone.
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thyroid stimulating hormone
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produced by anterior pituitary when hypothalamus produces thyrotropin-releasing hormone. Also called thyrotropin. stimulates growth of thyroid gland and they secretion of thyroid hormone. widespread effects on metabolic rate, body temp, etc.
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adrenocortiocotropic hormone
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growth of adrenal cortex and secretion of glucocorticoids, which regulate glucose primarily, include cortisol: fat and protein catabolism, stress response, tissue repair, anti inflammatory.
secreted by anterior pituitary when hypothalamus releases corticotropic releasing hormone. |
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prolactin
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secreted by anterior pituitary when hypothalamus releases thyrotropin releasing hormone. affects mammary glands and testes. causes milk synthesis in females and increased luteinizing hormone sensitivity in males.
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growth hormone
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aka somatotropin. produced by anterior pituitary when hypothalamus releases growth hormone releasing hormone. targets liver, bone, cartilage, muscle, fat. induces liver to produce IGF-1 (insulin growth factors) which have longer half life than GH. stimulate target cells in diverse tissues, protein synthesis (transcript) , lipid metabolism, carb metabolism, glucose sparing, electrolyte retention. TISSUE GROWTH.
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growth hormone cont.
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bone thickening and remodelling
secretion high during first 2 hrs of deep sleep peaks in response to vigorous exercise, GH levels decline with age |
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Pars Intermedia
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present in fetus, absent in adult. produces melanocyte-stim hormone in animals with skin, hair, feathers.. still are remnant cells in adult anterior lobe of pituitary, produce propiomelanocortin. it's not secreted. processed there to produce pain-inhib endorphins.
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Oxytocin
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produced by hypothalamus, stored and released by posterior pituitary. associated with sexual response, bonding between sexual partners and mother/breastfeeding infant, milk letdown, stimulates labor contractions,
negative vs. positive feedback here. |
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neuroendocrine reflex
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suckling infant- stim nerve endings- hypothalamus stimulated- release of oxytocin - milk letdown.
milk ejection also come from infant cry (higher brain functioning). |
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antidiuretic hormone
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increases water retention, reduces urine volume, prevents dehydration. aka vasopressin b/c causes vasoconstriction. stored and released by posterior pituitary on command by hypothalamus.
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negative feedback vs.
positive feedback |
increased target organ hormone levels inhibit further release of hormone.
positive feedback: release of hormone has amplifying effect. |
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Anatomy of Pineal gland
where changes in it throughout lifespan |
attached to roof of 3rd ventricle beneath the posterior end of the corpus callosum.
after age 7, in undergoes involution. down 75% by end of puberty, tiny mass of shrunken tissue in adults. |
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overall, what does it do
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synchronize circadian rhythms of daylight and darkness. synthesizes melatonin from serotonin during the night. fluctuates seasonally with changes in day lenght.
regulates timing of puberty? SAD- seasonal affective disorder. depression, sleepiness, irritibility,carb craving. |
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Thymus
plays a role in what 3 organ/fn systems where is it what does it do |
endocrine: thymopoietin, thymosin, and thymulin are hormones.
immune and lymphatic system. site of maturation of T-lymphocytes. its a bi-lobed gland in the mediastinum. does go through involution after puberty. |
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Thyroid
anatomy where appearance cells |
largest of the endocrine glands. two lobes + isthmus below the larynx. dark reddish brn due to rich blood supply, has follicular cells and parafolicular cells. the follicles are sacs that compose most of the thyroid. contain protein rich colloid w/ iodine. follicular cells are cuboidal epithelium that lines follicles.
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thyroid: hormones:
what are they and what do they do which cells do they come from |
secretes thyroxine (T4) and triiodothyronine (T3). T4 is converted to T3. Increases metabolic rate, O2 consumption, heat production, apetite, growht hormone secretion, alertness, quicker reflexes. Parafollicular cells secrete calcitonin with rising blood calcium. stimulates osteoblast activity and bone form.
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Parathyroid glands
where, how many function |
there are usually four of these, tiny, but can be up to 12. embedded in posterior surface of thyroid gland. secrete parathyroid hormone. Ca, Ca, Ca. increase blood Ca2+ levels. promotes synthesis of calcitriol. incr absorption of Ca in digestive tract. decr urinary excretion, increases bone resorption.
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adrenal glands
where are they what are the two parts |
small gland that sits on top of each kidney, they are retroperitoneal (in abdomen but not surrounded by membrane). adrenal cortex and medulla fromed by merger of two fetal glands with different origins and functions. similar to pituitary.
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adrenal medulla
what part is this again what does it release |
this is the inner core, 10 - 20%. has dual nature of endocrine gland and sympathetic ganglia. chromafin cells are modified sympathetic postganglionic neurons. when stimulated release catecholamines (epinephrine and norepinephrine + tr. dopamine) in blood.
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catecholamines:
what do they do, why releases |
epinephrine and norepinephrine. increases alertness and prepares body for physical activity. mobilizes high-energy fuels, lactate, fatty acid, glucose.
glycogenolysis and gluconeogenesis boost glucose levels. glucose sparing b/c inhibits insulin sectretion; muscles use fatty acids. increase blood pressure, heart rate, blood flow to muscles, breathing, metabolic rate, decreases digestion and urine production |
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adrenal cortex, anatomy
what does it produce, generally |
surrounds adrenal medulla and produces more than 25 steroid hormones called corticosteroids. it's the bulk of the adrenal gland.
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adrenal cortex
layers and what they secrete |
zona glomerulosa (thin outer layer): mineralocorticoids (salts)
zona fasciculata (thick middle layer): glucocorticods (sugars) zona reticularis ( narrow inner layer): sex steroids G--F--R |
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mineralocorticoids
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zona glomerulosa. they regulate electrolyte balance, as they're salts. one you need to know is aldosterone. stimulates Na+ retention (water retention) and K+ excretion
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glucocorticoids
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sugars. zona fasciculata. regulate metabolism of sugars primarily. includes cortisol. stimulate fat and carb catabolism, gluconeogenesis, and release of fatty acids and glucose in blood. crucial in stress response and tissue repair. short term anti-inflammatory, long term immunosuppressive.
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Sex steroids
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zona reticularis. these are androgens. this is a testosterone precursor. help set libido. large rold in prenatal male development. DHEA which is converted to testosterone. Estradiol: small quantitiy. sustains bone mass after menopause.
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Pancreas
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exocrine digestive gland and endocrine cell clusters (islets of Langerhans) found retroperitoneal and posterior to stomach. looks like a wad of chewing gum.
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Islets of Langerhans hormones (5) :
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Glucagon
Insulin somatostatin (also in hypothalamus) Pancreatic polypeptide Gastrin |
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glucagon
which cells pupose target organ (s) |
secreted by alpha cells
purpose is to maintain blood glucose levels between meals major target organ is the liver. stimulates gluconeogenesis and glycogenolysis. stim release of glucose into the circulation. targets adipose tissue, stim fat catabolism, release of fatty acids |
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insulin
which cells purpose |
secreted by beta cells . lowers blood glucose. secreted after big carb-rich meal. stimulates cells to absorb nutrients and store or metabolize them. promostes synthesis of glycogen, fat, protein. suppresses use of already stored fuels. not all tissues require insulin (brain and liver) but most do.
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somatostatin
which cells what does it do where else does this come from |
delta cells.
partially suppresses secretion of glucagon and insulin. inhibits nutrient digestion and absorption which prolongs absorption of nutrients. acts as both a paracrine and hormone when released from pancreas, not hypothalamus. |
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PP and gastrin
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pancreatic polypeptide and gastrin both have digestive fns.
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Control of blood sugar/ glucose
hyper vs. hypo glycemic hormones |
hyperglycemic hormones: elevate blood sugar.
glucagon, growth hormone, epinephrine, norepinephrine, cortisol, corticosterone hypoglycemic: lower blood sugar. only insulin. |
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Gonads
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produce hormones and germ cells.
ovaries: estradiol, progesterone, inhibin. testicular: testosterone, some weaker androgens, estrogen, inhibin. just need to name hormones for now. |
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Diabetes Mellitus 1
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diabetes just means excess urine. Type 1 Diabetes mellitus is hereditary. Comes on fast during early age or adult, only 5-10% of diabetics. beta cells of pancreas destroyed by autoimmune disorder. insulin levels below normal, they are hyper-glycemic. need insulin shots or inhaler, glucose monitoring, exercise, meal planning. Have pancreatic islet cell antibodies.
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Diabetes Mellitus type 2
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90 - 95% of diabetics. slow onset and comes on usually after age 40 but becoming more prevalent in kids due to obesity epidemic. Pancreatic beta cells are present, just becomming insulin resistant. at beginning of disease, insulin is high but body later stops making so much of it. no antibodies. still have high blood sugar (hyperglycemia). risk is heredity, age, obesity, sedentary lifestyle. treatment is diet, exercise, oral meds.
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Skin
endocrine functions |
keritanocytes convert cholesterol-like steroid into form of Vit. D using UV
(cholecalciferalol) |
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Liver
endocrine functions |
involved in production of at least 5 hormones:
cholecalciferol to calcidiol makes angiotensinogen, a prohormone involved in bl pressure. erythropoietin (makes red blood cells) hepcidin- iron regulation IGF-I that controls action of growth hormone. |
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kidneys,
endocrine functions |
play a role in production of 3 hormones
convert calcidiol to calcitriol, active form of Vit D secrete renin, enzyme that controls angiotensin (blood pressure) makes %85 of erythropoietin (stimulates blood marrow to make RBCs) |
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Stomach and Heart
endocrine functions |
heart: puts Na+ in urine, means water too. regulates blood pressure.
stomach: 10 enteric hormones from enteroendocrine cells. coordinates digestive motility and glandular secretion |
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Endocrine functions of some tissues
adipose osseous placenta |
adipose: leptin (apetite control)
osseous: osteocalcin placenta: estrogen, progesterone (regulates pregnancy, stimulates development of fetus and mammary glands) |
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WHat are the 3 chemical classes of hormones
WHat do they look like how made |
steroids: it's got cholesterol. 4 connected rings. differs in functional groups attached.
monoamines: 4 iodines, 1 amine (NH), 1 or 2 C rings peptides/glycoproteins: like any protein, chain of amino acids. at first its an inactive preprohormone. 1st am.ac. signal for ER, signal removed to make "prohormone", gogi cleaves off the Pro part. |
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Monoamines
talk about two and how made |
melatonin is synthesized from amino acid tryptophan and other monoamines from amino acid tyrosine.
thyroid hormone is composed of two tyrosines sleepy amino acid |
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Thyroid hormone
how is it made in the thyroid gland |
1. iodide absorption and oxidation to iodine, from blood into colloid. 2. the cells surrounding the colloid release thyroglobulin 3. the thyroglobulin combines with the iodine 4. thyroglobulin again uptaken by cells. hydrolysis. 5. release of T3 and T4 in blood. stays in colloid because iodine toxic to cells!
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Hormone transport
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monoamines and peptides hydrophilic, just float around in blood till hit target. steroids are hydrophobic. have to bind to transport proteins, only unbound hormone leaves capillaries to reach target cell. the trans.proteins. protect the hormone from being broken down by enzymes in plasma and liver and from being filtered out of blood by kidneys.
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hormone receptors and mode of action
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hormones stimulate only cells with receptors, which are protein-glycoprotein molecules on plasma membrane, cytoplasm, or in nucleus. receptors act like SWITCHES, to turn on metabolic pathways when hormone binds. usually each target cell has few thousand receptors for given hormone.
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Receptor-hormone interactions exhibit
1. 2. |
1. specificity
2. saturation |
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hydrophobic hormones
how do they target cells, interact |
penetrate pm and enter nucleus (diffuse right through pm b/c they're a lipid). many of these have nuclear receptors, they act directly on genes changing target cell physiology. they are transcription factors.
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hydrophilic hormones
how do they target cells, interact |
cannot penetrate into target cell. must stimulate physiology indirectly. never goes in cell. just activates that switch and activates a second messenger system
these include monoamines and peptides, with the exception of thyroid. thyroid is not a steroid but is hydrophobic anyway. |
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thyroid hormone
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the metabolic rate controller.
enters target cell by diffusion, mostly as T4 with little metabolic effect. target cell converts T4 to more potent T3. it's a transcription factor. causes protein synthesis. |
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Peptides and catecholamines
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you need to look at diagram in book. hormone binds to receptor. G-protein bound to receptor eats a GTP and activates andenylate cyclase. eats an ATP and makes cyclic AMP. cAMP makes a protein kinase. pk phosphorylate enzymes, activating some and deactivating others. these catalyze metabolic rxns. wide range of effects on cell. p. 662.
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Enzyme amplification
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for example, cAMP activates >1 protein kinase. hormones are very potent. one hormone molecule triggers synthesis of many enzyme molecules. very small simulus can have very large effect. circulaing concentrations very low.
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how does a body modulate target cell sensitivity
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change the number of receptors, up regulation or down regulation (down reg happens with long term exposure to high hormone concentrations)
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hormone interactions
3 |
synergistic: multiple hormones act together for greater effect. FSH and testosterone both incr sperm.
permissive: one hormone enhances target cell's response to later hormone. estrogen prepares the way for progesterone in pregnancy antagonistic: one hormone opposes the action of another, insulin lowers blood sug, glucogen raises it. |
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hormone clearance
what is it how does it happen what are the terms you need to know |
hormone signals have to be turned off when served purpose, most taken up and degraded by liver and kidney, excreted in bile/urine. MCR = metabolic clearance rate. rate at which it is removed. different for adults and kids. half life is time takes to remove 50% from blood.
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stress
definition what are the stages, what are they called collectively |
caused by any situation that upsets homeostatsis and threatens one's physical or emotional well-being.
GAS - general adaptation syndrome alarm rxn, stage of resistance, stage of exhaustion |
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alarm reaction
what hormones what happens what organ is involved |
initial response to stress. dominated by catecholamines from the sympathetic nervous system/adrenal medulla
prepares body for fight or flight stored glycogen is consumed |
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stage of resistance
what hormones what happens what organ is involved |
after few hours, glycogen reserves gone, but brain still needs glucose. alternate fuels. stage dominated by cortisol. hypothalamus secretes corticotropin releasing hormone. pituitary secretes adrenocorticotropic hormone. stimulates adrenal cortex to secrete cortisol and other glucocorticoids. promotes breakdown of fat and protein into glycerol,fatty acids, protein, etc. for gluconeogenesis.
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stage of resistance
adverse effects |
cortisol has glucose sparing effect- inhibits protein synthesis leaving free amino acids for gluconeogenesis.
adverse effects of cortisol , depress immune fn, incr. susceptibility to infect and ulcers, lymphoid tissues atrophy, antibody levels drop, wounds heal poorly. |
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stage of exhaustion
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chronic stress continues and fat reseves are gone, homeostasis is overwhelmed. marked by rapid decline and death. protein breakdown and muscle wasting, loss of glucose homeostasis b/c adrenal cortex stops producing glucocorticoids. heart and kidney infection or overwhelming infection.
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eicosanoids and paracrine signaling
what are they how are they unlike neurotransmitters and hormones |
paracrines- chemical messengers that diffuse short distances and stimulate nearby cells. unlike neurotransmitters not produced in neurons. unlike hormones, not transported in blood
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eicosanoids and paracrine signalling
name 4 where do they come from what does it do what determines whether something is behaving as a paracrine or hormone or neurotransmitter |
-a single chemical can act as a hormone, paracrine, or even neurotransmitter in a different location.
histamine-from mast cells in connective tissue, causes relaxation of blood vessesl / vasodilation nitric oxide-from endothelium of blood vessels, causes vaso dilation somatostatin- from gamma cells, inhibits secretion of alpha and beta cells of pancreas catecholamines- diffuse from medulla to cortex |
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eicosanoids
what are they from what are them made what do they do, generally |
important family of paracrines that are derived from fatty acid called arachidonic acid, mediate allergic and inflammatory response.
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eicosanoids
name 3 |
prostacyclin- inhibits blood clotting and vasoconstriction
thromboxanes-produced by blood platelets after injury, overrides prostacyclin, stimulates vasoconstriction and clotting. prostaglandins- diverse family with diverse effects |
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endocrine disorders
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variations inhormone concentration and target - cell sensitivity that have noticeable effects on the body
hyposecretion hypersecretion |
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hyposecretion
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not enough. tumor or lesion destroys gland or interferes w its ability to receive signals. head trauma affects pituitary gland's ability to make ADH, causes diabetes insipidus, chronic polyuria. autoantibodies fail to distinguish person's own gland from foreign matter
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hypersecretion
what happens give 2 ex. |
excessive hormone release, tumor, autoimmune disorder. pheochromocytoma: tumor of adrenal medulla, excessive epinephrine/ norepinephrine
toxic goiter: Graves disease: autoantibodies mimic effect of TSH on thryoid, causing thyroid hypersecretion |
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pituitary disorders
what hormone would you have problems with 3 diseases |
hypersecretion of growth hormone
acromegaly-thickening of bones and soft tissues, hands, feet, face problems in childhood or adolescence, giganticism if hypersec, dwarfism if hypo- rare b/c hormone made by humans |
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thyroid disorders
4 diseases hormone you have probems with |
congenital hypothyroidism (decreased thyroid hormone
formally called cretinism. oral thyroid hormone. severe. myxedema is adult hypothyroidism. goiter - endemic goiter - enlargement of thyroid glandfrom dietary iodine deficiency. no neg feedback from TH stimulates TSH. toxic goiter- autoantibodies mimic effect of TSH.yesTH. |
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parathyroid disorders
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hypoparathyroidism-surgical excision durine thyroid surgery, fatal tetany in 3 -4 days due to rapid decline in blood Ca
hyperparath- excess PTH secreted. tumor. bones get soft, deformed. Ca and phosphate blood levels increase. promotes renal calculi formation. |
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adrenal disorders
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cushing syndrome- excess cortisol. hyperglycemia, hypertension, weakness, endema, rapid muscle and bone loss due to protein catabolism. abnormal fat deposition (moon face and buffalo hump)
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diabetes mellitus
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most prevalent metabolic disease in the world. Type 1 and type 2 already discussed. either hyposecretion or inaction of insulin. polyuria(excess urine), polydipsia (thirst), polyphagia (hunger). elevated blood glucose, glucose in urine, ketones in urine. excess glucose enters urine and water follows it.
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pathogenesis of DM
breakdown of fat and proteins for food, effects |
cells must rely on fat and proteins for energy needs. fat catabolism increases free fatty acids and ketones in blood. ketonuria promotes irregular heartbeat, neurological issues, ketoacidosis occurs as ketones decr blood pH , deep, gasping breathingand diabetic coma
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pathogenesis of DM
effects of hyper glycemia |
chronic hyperglycemia: neuropathy and cardiovascular damage. arterial damage in retina and kidneys (common in type 1) atheosclerosis leads to heart failure (type 2). diabetic neuropathy: nerve damage from impoverished blood flow, erectile dysfn, incontinence, poor wound healing, loss of sensation from area
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