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36 Cards in this Set
- Front
- Back
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FUNCTIONS
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A. to help regulate body activity through the release of hormones into the blood/lymph (ductless glands)
B. alter existing cell activities (enhance or diminish) through the actions of the chemical hormones on the cells C. closely integrated with nervous system in regulating body activities (maintain homeostasis), often referred to as the NEUROENDOCRINE SYSTEM. 1. endocrine system is long lasting but slow to get going hormones enter blood -> organs -> removed by kidneys wide spread effects 2. nervous system is short lasting but fast starting electrical signals sent down axons to organs localized effects 3. HYPOTHALAMUS is the link between the nervous and endocrine systems and is referred to as a NEUROENDOCRINE ORGAN |
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HORMONES
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A. chemicals (mostly proteins and some steroids) secreted by cells into extracellular fluids (including
blood) that regulate existing cell functions B. SPECIFICITY OF HORMONES 1. TARGET CELLS: cells affected by the particular hormone 2. RECEPTORS for specific hormones are found only on target cells |
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CONTROL OF HORMONE RELEASE
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A. primarily through negative feedback loops: increased hormone concentration inhibit hormone release
B. three main control mechanisms for hormone release other than negative feedback; stimulation of hormone release may be from more than one control mechanism 1. HUMORAL STIMULUS (simplest) a. secretion is in response to changing blood concentrations of ions and nutrients b. lo [Ca+] -> PTH release 2. NEURAL STIMULUS (rare) a. nerve fibers stimulate hormone release b. stress -> symp N.S. -> adrenal medulla -> norepinephrine 3. HORMONAL STIMULUS (by tropic hormones) hormones stimulate the release C. NERVOUS SYSTEM can override normal endocrine controls to maintain homeostasis |
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HYPOTHALAMUS
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1. secretes tropic hormones regulating release of hormones from the anterior pituitary (homeostatic control)
prolactin inhibitory hormone (PIH) thyrotropic releasing hormone (TRH) prolactin releasing hormone (PRH) growth hormone releasing hormone (GHRH) gonadotropic releasing hormone (GnRH) growth hormone inhibiting hormone (somatostatin) (GHIH) corticotropic releasing hormone (CRH) 2. secretes hormones to be stored in the posterior pituitary for later release by the posterior pituitary Antidiuretic hormone (ADH) Oxytocin (OT) |
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PITUITARY GLAND (HYPOPHYSIS)
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LOCATION: in sella turcica of sphenoid bone
SHAPE: pea-sized, round, bilobed (anterior and posterior) attached to HYPOTHALAMUS by INFUNDIBULUM |
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ANTERIOR LOBE: ADENOHYPOPHYSIS
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a. hormone production/secretion CONTROLLED by secretion of horm. from hypothalamus
b. two classes of hormones from adenohypophysis i. TROPINS: regulate other endocrine glands TSH, ACTH, FSH, LH ii. NON-TROPIC HORMONES: GH, PRL MSH c. ANTERIOR PITUITARY HORMONES AND HYPOTHALAMIC REGULATORS ** indicates a hormone produced in hypothalamus |
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GROWTH HORMONE - GH
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TARGET: most tissue cells
FUNCTION: stimulate protein synthesis/growth, mobilize fat for energy, conserves glucose (^blood glucose) REGULATION: **GHRH: growth hormone releasing hormone **GHIH (SOMATOSTATIN):growth hormone inhibiting hormone -FEEDBACK conc. of GH in blood |
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THYROID STIMULATING HORMONE - TSH
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TARGET: thyroid gland
FUNCTION: stimulates normal thyroid growth, stimulates thyroid hormone secretion REGULATION: **TRH - thyrotropin releasing hormone **GHIH - FEEDBACK conc. of TSH, TH in the blood |
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ADRENOCORTICOTROPIC HORMONE - ACTH
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TARGET: adrenal cortex of adrenal gland
FUNCTION: stimulate corticosteroid hormone secretion to combat the effects of stress REGULATION: **CRH: corticotropin releasing hormone - feedback conc. of ACTH and corticosteriods in blood |
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MELANOCYTE STIMULATING HORMONE: MSH
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TARGET: melanocytes in skin
FUNCTION: stimulate production of melanin REGULATION: hypothalamic neuronal stimulus of adenohypophysis |
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PROLACTIN: PRL
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TARGET: mammary glands
FUNCTION: stimulate milk production REGULATION: **PRH: prolactin releasing hormone **PIH: prolactin inhibiting hormone ESTROGEN: low estrogen, stimulates PIH and inhibits PRL hi estrogen, stimulates PRH and stimulates PRL SUCKLING: increases PRL |
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GONADOTROPINS
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LH & FSH
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LUTEINIZING HORMONE: LH
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TARGET: gonads
FUNCTION: stimulate secretion of gonadal hormones females: induce ovulation, stimulate estrogen/progesterone secretion, assists in egg maturation males: testosterone production |
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FOLLICLE STIMULATING HORMONE: FSH
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TARGET: gonads
FUNCTION: stimulate egg and sperm production and estrogen production |
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REGULATION OF BOTH FSH AND LH
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**GnRH: gonadotropin releasing hormone
- feedback: conc. of testosterone, estrogen, progesterone in blood NO RECEPTORS FOR HORMONES ON TARGET CELLS UNTIL PUBERTY |
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POSTERIOR LOBE OF PITUITARY: NEUROHYPOPHYSIS
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a. stores hormones produced by hypothalamus OT, ADH
b. CONTROLLED by nervous stimulation by hypothalamus c. POSTERIOR PITUITARY AND THE HYPOTHALAMIC HORMONES STORED THERE |
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OXYTOCIN: OT
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TARGET: smooth m.: especially in uterus and in breast ducts
FUNCTION: stimulates contraction of uterus during labor, allows "milk let-down" for nursing, promotes sexual arousal and "bonding" behaviors in males/females REGULATION: + FEEDBACK: stretch of uterus/cervix toward the end of child birth ^ OT release causing more uterine contractions ALSO in response to stretching of the breasts due to milk production (a function of PRL), OT is stimulated, or when suckling occurs, milk is let down. |
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ANTIDIURETIC HORMONE: ADH (diuresis = urine production)
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TARGET: kidneys, blood vessels
FUNCTION: regulate water and electrolyte balance by causing vasoconstriction (causing less urine to be produced) when BP drops or when dehydration occurs REGULATION: fluid balance/volume is monitored by OSMORECEPTORS if the blood concentration increases or if fluid volume falls, these receptors are stimulated and tell the hypothalamus to produce more ADH and tell the posterior pituitary to release the ADH. Less urine is made, fluid volumes stabilize and less ADH is released. HYPOSECRETION: DIABETES INSIPIDUS: large urine output POLYUREA large thirst POLYDIPSIA |
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THYROID GLAND
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LOCATION: anterior side of trachea below larynx
SHAPE: BUTTERFLY: rt. and lt. lobes and ISTHMUS FUNCTION: production and secretion of a. THYROID HORMONE: TH b. CALCITONIN: CT |
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THYROID HORMONE (metabolic hormone) THYROXINE
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TARGET: most cells in the body
FUNCTION: metabolic hormone stimulates use of O2 in breakdown of fats/sugars, stimulates protein production, increases body temperature REGULATION: TRH: from hypothalamus TSH: from anterior pituitary -FEEDBACK: ^ TH in blood, inhibit TSH..... NEED FOR ENERGY: increased production during pregnancy, cold climate (HYPOTHALAMUS WILL OVERRIDE THE NEGATIVE FEEDBACK) GHIH: from hypothalamus inhibits TSH ..... ABUNDANCE OF IODINE: needed to make the hormone TH |
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CALCITONIN: CT
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TARGET: bones, osteoblasts
FUNCTION: decrease blood calcium by stimulating bone formation REGULATION: hi Ca in blood stimulates CT lo Ca in blood inhibits CT release |
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PARATHYROID GLANDS
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LOCATION: embedded in the posterior aspect of the thyroid gland
SHAPE: small clusters of cells usually 4 to 8 clumps FUNCTION: produce and secrete PTH PARATHYROID HORMONE: PTH TARGET: bones (osteoclasts), kidneys FUNCTION: increase blood Ca levels by breaking down bone, causing Ca retention from urine, and activation of VIT D for Ca uptake from the intestine REGULATION: lo calcium in blood stimulates PTH hi calcium in blood inhibits PTH |
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ADRENAL (SUPRARENAL) GLANDS
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LOCATION: above kidneys
SHAPE: pyramidal, outer region = CORTEX, inner region = MEDULLA FUNCTION: maintain homeostasis by combating the effects of stress |
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ADRENAL CORTEX HORMONES: steroid horm LONG TERM STRESS CONTROL
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MINERALOCORTICOIDS: ALDOSTERONE
GLUCOCORTICOIDS: CORTISOL GONADOCORTICOIDS: ANDROGENS (TESTOSTERONE) and ESTROGENS |
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MINERALOCORTICOIDS: ALDOSTERONE
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TARGET: kidneys causing reabsorption of Na+ from urine K+ excretion
FUNCTION: regulate electrolyte (Na, K) balance in body fluids by causing uptake of electrolytes from urine (water will follow) REGULATION: RENIN-ANGIOTENSIN SYSTEM *kidney cells stimulated when blood volume drops or when solute conc. in blood drops. *kidney cells release RENIN into blood *renin changes ANGIOTENSINOGEN -> ANGIOTENSIN II through a series of events *angiotensin II stimulates aldosterone release Lo Na and Hi K ION concentrations stimulate aldosterone release ACTH from the ant. pit. during stress ^ aldosterone release to ^BP to meet body needs during stress ATRIAL NATRIURETIC FACTOR hormone from the heart when BP is high. Inhibits renin/aldosterone |
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GLUCOCORTICOIDS: CORTISOL
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TARGET: most body cells
FUNCTION: help to resist the effects of stress by increasing blood sugar: use fats for energy and gluconeogenesis REGULATION: CRH, ACTH increase release -FEEDBACK |
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GONADOCORTICOIDS: ANDROGENS (TESTOSTERONE) and ESTROGENS
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TARGET: most body cells
FUNCTION: puberty onset REGULATION: ACTH |
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ADRENAL MEDULLA: EPINEPHRINE, NOREPINEPHRINE brief stress regulator
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TARGET: cardiac muscle cells, smooth muscle lining bv's
FUNCTION: "fight or flight response", increase heart rate, constrict blood vessels to ^BP REGULATION: stress increases the release of these hormones, SYNS stimulates release |
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PINEAL GLAND (EPIPHYSIS)
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LOCATION: in brain, near third ventricle and posterior commissure
SHAPE: pea sized gland FUNCTION: produce, release MELATONIN |
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MELATONIN
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TARGET: most cells of body
FUNCTION: puberty onset, regulate body cycles and patterns (sleep, eat, temp...) REGULATION: by natural light (inhibits melatonin) and dark |
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THYMUS GLAND
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LOCATION: below sternum, above heart
SHAPE: 2 lobes, big during childhood, atrophies with age FUNCTION: production of thymosin THYMOSIN TARGET: white blood cells, LYMPHOCYTES FUNCTION: matures WBC’s into T-lymphocytes, cells of the immune system Regulated by immunity needs, age |
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PANCREAS
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LOCATION: inf. and post. to stomach, between duodenum and Spleen
SHAPE: long, narrow FUNCTION: production of insulin, glucagon (ISLETS OF LANGERHANS) |
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GLUCAGON: (from alpha cells)
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TARGET: liver
FUNCT: inc. blood sugar & dec. blood amino acids by glycogenolysis, gluconeogenesis REGULATION: hi amino acids or low blood sugar stimulate glucagon hi glucose, somatostatin inhibit glucagon |
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INSULIN: (from beta cells)
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TARGET: muscle cells and other tissue cells
FUNCTION: decrease blood sugar by glucose uptake into cells increase cellular use of glucose increase glycogenesis, lipogenesis increase protein synthesis REGULATION: hi AA, hi fatty acids, hi glucose stimulate insulin lo glucose, somatostatin inhibit insulin HYPOSECRETION DIABETES MELLITUS: hi blood sugar, hi sugar in urine, increased urine production polyurea, polydipsia, polyphagia (eat more) increased protein degradation, increased fat breakdown --> buildup of KETOACIDS in blood (decreased pH) type I (IDDM): no insulin production, hard to control, juvenile onset type II (NIDDM): lo insulin production or receptors unable to respond to insulin. highly genetic, weight related, age onset |
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GONADS: TESTICLES AND OVARIES
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cover in reproductive chapter
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CHAPTER 16 THE ENDOCRINE SYSTEM
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CHAPTER 16 THE ENDOCRINE SYSTEM
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