EXSC 224 Week 7 Notes
EXSC 224 Week 7 Notes Exsc 224
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This 10 page Class Notes was uploaded by Jane Warther on Friday February 26, 2016. The Class Notes belongs to Exsc 224 at University of South Carolina taught by Dr. Thompson in Spring 2016. Since its upload, it has received 35 views. For similar materials see Anatomy and Physiology 224 in Education and Teacher Studies at University of South Carolina.
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Date Created: 02/26/16
CHP 16 Major Endocrine Organs Week 7 2/23/16 Lecture 3 o ADH Overproduction Syndrome of inappropriate ADH secretion (SIADH) Compound problem Symptoms: Hyponatremia- low blood concentration of sodium o Dilute blood, salt concentrations go down Inappropriately elevated urine osmolarity (>200 mOsm/kg) Excessive urine sodium excretion (Una >30 mEq/L) Decreased serum osmolarity Cause Hypovolemia ADH-secreting tumor (non-pituitary) Water recovery nephron’s in kidneys recover water Bowman’s capsule- where filtration takes place in kidney o Technically part of nephron o Blood supply comes in nephron, branches into capillaries in capsule o Water and small proteins and electrolytes leave capillaries and enter nephron o The filtrate ends up in ducts or tubes, these tubes are non- linear called convoluted, proximal convoluted tube dips (descending part is called loop of henle)comes back up forms another convoluted tube, this distal convoluted tube merges with collecting duct o If water not recovered shortly after entering collecting duct it is gone and will end up in urine o Filter out fluid, fluid passes through set of tubules, makes way to collecting ducts o As water passes through convoluted tube, we recover lots of water o PCT(proximal convoluted tube) is where most water is recovered-60% o Reabsorb it, it is kept in body o Kidneys filter and then reabsorb most of what they filter out o After PCT only a little of water is recovered Aquaporins- water pores o Appear within cells collecting duct only when ADH is secreted Allows us to recover more water o Allow for more water to be recovered or reabsorbed o Help recover at least a meaningful portion of 40% that made it to collecting duct o ADH doesn’t increase water by itself, it conserves it o Have ADH production and drink water then increase blood volume o Secrete ADH, urine volume decrease, concentration of anything like sodium in the urine will increase Thyroid Gland Sits at base neck, straddles either side of trachea, connected by isthmus Amino-based hormone Secretes 2 hormones o Thyroid hormone Major metabolic hormone Permissive hormone Growth hormone doesn’t work unless TH is present o Calcitonin Lowers blood calcium Consists of two related iodine-containing compounds o Number after T tells how much iodine is bound to the tyrosine o T4- thyroxine Has two tyrosine molecules plus four bound iodine atoms o T3- triiodothyronine Has two tyrosines with three bound iodine atoms Table salt has potassium iodide o Everyone would be iodine efficient if there wasn’t any in table salt o No iodine don’t make enough T3 or T4 o Ocean fish source of iodine TH is concerned with o Glucose oxidation Promotes use of glucose and fats for energy o Increasing metabolic rate o Heat production TH plays a role in: o Maintaining blood pressure o Regulating tissue growth o Developing skeletal and nervous systems o Maturation and reproductive capabilities o Permissive hormones Negative feedback control o More T3 and T4 secreted, inhibit hypothalamus from producing TRH Hypo-thyroid disorder o Cretinism- children Low metabolic rate Growth retardation Developmental delay Other abnormal features Can be due to deficiency of iodine in the mother’s diet during pregnancy o Myxedema- adults Low metabolic rate Gain weight Skin and tissue disorder usually due to severe prolonged hypothyroidism Result of iodine deficiency or disruption in any part of pathway Some people forced to have it if they have thyroid cancer and gland needs to be removed o Goiter- swollen thyroid gland At base of neck Based on severity and length of deficiency Can have with hyper or hypo thyroid disorder Hyper- thyroid disorder o Grave’s disease Autoimmune disorder Immune system attacks thyroid gland o Stimulates TH independent of TSH Over activity of the thyroid gland Inflammation of the tissues around the eyes causing swelling Increased metabolic rate, sweating, rapid and irregular heartbeat, nervousness, weight loss, protruding eyeballs (exophthalmos) Can have goiter too o Constant stimulation of gland to produce TH, gland hypertrophies Thyroid not under negative feedback gland Treated by killing gland and making you hypo Humoral Calcium ion concentration in the blood Calcium homeostasis of blood: 9-11mg/100ml Calcitonin o Regulates parathyroid hormone Negative feedback mechanism o Rising blood levels of calcium levels(drink glass of milk) o Stimulus to secrete calcitonin from the thyroid gland Not really potent Job to inhibit secretion of parathyroid hormone Inhibit actions of parathyroid hormone Parathyroid hormone causes breakdown of bone o Calcitonin stimulates calcium salt deposit in bone Osteoblasts take calcium out of blood and deposit it in bone Calcium blood levels decrease and homeostasis is restored Parathyroid Gland Parathyroid hormone (PTH) o Embedded within thyroid gland o Amino-acid base hormone PTH raises blood calcium levels (antagonistic to calcitonin) o Stimulates osteoclasts to break down bone o Increase calcium absorption from food o Stimulate kidneys to reabsorb calcium filtered out o Activation of vitamin D in kidneys Humoral (calcium ion concentration in the blood ) regulated- negative feedback mechanism o Regulated by calcium levels in the blood o Low blood calcium concentration low, stimulates PTH to raise blood calcium levels back up to homeostasis Hyper-parathyroidism o Rare- leach bone minerals Hypo-parathyroidism o Deficiency o Causes hypocalcemia o Increases spontaneous membrane depolarization Adrenal (Suprarenal) Glands 2 glands in 1 o Adrenal medulla- neural tissue that acts as part of the SNS o Adrenal cortex- secretes steroid hormones Synthesizes and releases steroid hormones called corticosteroids Different corticosteroids are produced in each of the three layers Zona glomerulosa- mineralocorticoids (chiefly aldosterone) Zona fasciculate- glucocorticoids (chiefly cortisol) Zona reticularis- gonadocorticoids (chiefly androgens) Aldosterone Regulation A steroid Primary job to regulate water o Regulates water through regulating sodium-reabsorption in the kidneys o The direction sodium moves is the direction water moves o Regulation of sodium regulates BP/ blood volume Regulators of aldosterone o Increased potassium in blood Stimulus elevated potassium levels Reabsorb sodium get rid of potassium Negative feedback control Lower potassium levels, stop secreting aldosterone o Decreased blood pressure Kidneys detects low blood volume Secrete renin An enzyme that stimulates angiotensin II(a hormone) Will stimulate aldosterone from adrenal cortex that increases potassium excretion and absorption of sodium and increase blood volume and blood pressure o Increased stress Not negative feedback o Increase blood volume, increase BP Secretes atrial natriuretic peptide (ANP) when heart is stretched Antagonistic to aldosterone , inhibits aldosterone secretion Makes you go to restroom Produce more urine because you reabsorb less volume Decreases BP/blood volume Hypo-aldosteronism o Addison’s disease Hyposecretion of adrenal cortex Includes: mineral corticoids and glucocorticoids Symptoms: Severe dehydration Hypotension Low blood glucose Low Na+ (sodium) High K+ (potassium) Hypersecretion o Aldosteronism Adrenal cortex tumor Over activity of the cells in the zona glomerulosa 2 major effects o Hypertension and edema Increase of blood volume o Loss of potassium Salt concentration normal Lecture 4 2/25/16 Glucocorticoid Cortisol- stress hormone (steroid) o Circadian pattern (diurnal) o High levels early in the morning o Hypothalamus o ↓ o CRH –amino-acid based o ↓ o Anterior pituitary o ↓ o ACTH –amino-acid based o ↓ o Adrenal Gland o ↓ o Cortisol- steriod High levels of cortisol inhibits the hypothalamus Negative feedback control Important stress hormone o Prepares body to do things o Prepares for physical stress Give body energy sources it needs Promotes: gluconeogenesis (conversion of amino-acids to glucose ), occurs quickly Lipolysis- occurs quickly Proteolysis o Breakdown of proteins o In skeletal muscle o When cortisol is secreted chronically in high levels breaks down skeletal muscle Will lose lean tissue o Prolonged stress Insulin resistance Acutely- regulate substrate production Long term- proteolysis, and immune function Decreases Inflammation Immune function o Compromises it ,more susceptible to illness Long term effects Hyposecretion o Addison’s disease- glucocorticoid and mineral corticoids deficits o Low levels of ACTH means you have low levels of cortisol Cause can vary o S+S Dehydration Low sodium concentrations Hypovolemic hypotensive Hypersecretion o Cushing’s syndrome- excess glucocorticoid(cortisol), don’t know why o Cushing’s disease- excess ACTH due to tumor in anterior pituitary ACTH travel to adrenal gland to hypersecretion ACTH and cortisol Hyperglycemia Skeletal muscle atrophy Loss of bone mass Edema- accumulation of water in extra-cellular space Change in skin color Redistribution of adipose Buffalo hump on back of neck Poor wound healing Elevated ACTH , aldosterone levels increase Develop advanced heart disease due to metabolic increases causing arthrosclerosis Gonadocorticoids Made by zona reticularis in adrenal gland Main secretions are: ANDROGENS→ Testosterone (precursor to estrogen, need it to produce estrogen) → Estrogen o Androstenedione o Dehydroepiandrosterone (DHEA) Production/secretion of testosterone and estrogen insignificant compared to gonads during puberty Anabolic steroid Adrenogenital syndrome- hypersecretion o Males- early puberty and male sex characteristic and sex drive Some of the testosterone may be converted to estrogen and develop breasts- before puberty After puberty- increase of testosterone converted to estrogen may cause increased sex drive o Females- masculinization Beard, body hair (irreversible), increased sex drive, and enlarged clitoris Stress and the Adrenal Gland Adrenal medulla o Secretes Amino-acid based hormone- epinephrine Hormonal equivalent of nor-epinephrine Under neural control of sympathetic nervous system All preganglionic fibers secrete acetylcholine Stimulate sympathetic nervous system , stimulate release of hormone Effects last longer because hormone doesn’t leave the blood as fast Dopamine- neurotransmitter, but insistence it acts as hormone(PIH) Norepinephrine- primarily neurotransmitter From preganglionic fibers Epinephrine- hormone Adrenal Cortex o fight or flight reflex- sympathetic nervous system catecholamine(norepinephrine/epinephrines) deficiency not a problem! (if limited to adrenal medulla) catecholamine hypersecretion- (pheochromocytoma) hyperglycemia, ↑ BMR, ↑HR, hypersecretion, sweating Regulation of Blood Glucose Levels glucagon- increases blood glucose o secreted by pancreas(both endocrine and exocrine gland) o amino-acid based hormone o secreted between meals during fasting o job is to help raise blood glucose levels to desired ranged o blood glucose falls(stimulus)→ cells in pancreas detect decrease in blood glucose, alpha islet cells also produce and secrete glucagon→ glucagon circulates out and targets liver → stimulates liver to breakdown stored glycogen into glucose→ glucose released into blood and raises blood glucose→ return to homeostasis o another job is to supply energy substrates insulin- decreases blood glucose o secreted by pancreas o protein, amino-acid based hormone o blood glucose levels rise(stimulus)→ detected by beta islet cells in pancreas→ beta islet produce and secrete insulin→ stimulates glycogen formation in liver from glucose, stimulates glucose uptake by cells→ blood glucose falls to normal range and homeostasis is restored Consequences of insulin deficit (diabetes mellitus=sweet urine) need insulin to survive type 1- insulin dependent or juvenile diabetes o beta islet cells die o don’t produce enough insulin o can happen in adults, but usually in children o blood glucose elevated type 2- non-insulin dependent or adult on-set diabetes (most common) o produce insulin but only intake a limited amount of glucose o genetic link o resistant to insulin o blood glucose elevated / gestational diabetes- 4% of pregnant women o 80-90% probability of developing type 2 diabetes later in life Pineal Gland- Brain Sand In epithalamus in diencephalon o secretes melatonin(derived from serotonin)- hormone suppressed by light exposure circadian rhythm control induces sleep light lowers melatonin secretion o effects shift workers o to deal with do light therapy helps reset circadian clock and when you secrete melatonin seasonal affective disorder- depression with high risk of suicide o best treatment- light therapy anti-oxidant Quiz 4 1. Name the tissue that secretes CRH. -hypothalamus → ACTH→ Cortisol→ Aldosterone 2. What is Grave’s disease? -Auto-immune disease that results in hyperthyroidism 3. Excess water retention with normal plasma Na+ concentrations is associated with what hormone? - Aldosterone 4. What is the class of receptors for thyroid hormone to bind to? -intra-cellular 5. What is PTH and what is its primary action? -parathyroid hormone and it raises blood calcium levels by breaking bone down Cortisol, aldosterone, estrogen, progesterone, testosterone- STEROIDS
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