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Endocrine System
Ch. 17 Vocab
124
Anatomy
Undergraduate 2
01/30/2012

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Term
Exocrine Glands
Definition
Glands that secrete their products into ducts that lead to the external environment.
Term
Endocrine Glands
Definition
Glands that secrete their products (hormones) into the bloodstream. or release paracrines that effect only target cells.
Term
Endocrine System
Definition
Glands, Tissues, and cells that secrete hormones
Term
Endocrinology
Definition
the study of the endocrine system and the diagnosis and treatments of its disorders
Term
Hormones
Definition
chemical messengers that are transported by the bloodstream and stimulate physiological response in cells of another tissue or organ. Often a considerable distance away.
Term
Hormone Receptors
Definition
-hormones stimulate only cells with receptors for them
-receptors are proteins or glycoproteins(on plasma, in cytoplasm, or in the nucleus)
-each target cell has several thousand receptors
-Specificity and Saturation
Term
Specificity
Definition
there is a specific receptor for each hormone
Term
Saturation
Definition
when all receptor molecules are occupied by hormone molecules.
Term
Target Cell Sensitivity
Definition
Adjusts by number of receptors.
Up-regulation and down-regulations.
Term
Up-Regulation
Definition
the number of receptors is increased so the sensitivity is increased.
Term
Down-Regulation
Definition
reduces number of receptors. sensitivity decreases. Common with long term exposure to high hormone concentrations.
Term
gap junctions
Definition
pores in cell membrane allow signaling molecules, nutrients and electrolytes to move from cell to cell
Term
neurotransmitters
Definition
released from neurons to travel across synaptic cleft to second cell.
Term
Paracrine
Definition
local hormones. secreted into tissue fluids to affect nearby cells.
Term
Hormone Chemistry
Definition
steroids, peptides and glycoproteins, monoamines.
ALL HORMONES ARE DERIVED FROM CHOLESTEROL OR AMINO ACID
Term
Steroids
Definition
derived from cholesterol and secreted by gonads and adrenal glands.
ex:estrogens, progesterone, testosterone, cortisol, coritcosterone, aldoesterone, DHEA, and calcitrol
Term
peptides and glycoproteins
Definition
created from chains of amino acids and secreted by pituitary and hypothalamus.
ex: oxytocin, ADH, releasing and inhibiting hormones and anterior pituitary hormones.
Term
Monoamines
Definition
Biogenic amines. derived from amino acids and secreted by adrenal, pineal, and thyroid glands.
EX: epinepherine, norepinepherin, melatonin, and thyroid hormone.
Term
Peptide Synthesis
Definition
synthesized same way as proteins.
Term
preprohormone
Definition
first stage: INACTIVE. signal peptide that guides into the rough ER
Term
Prohormone
Definition
signal peptide removed. Golgi body does final transformation to HORMONE and is packaged for secretion.
Term
insulin synthesis
Definition
preproinsulin becomes proinsulin. C peptide levels gauge how much insulin is produced in the body.
Term
Enzyme Amplification
Definition
Hormones are extremely potent, one hormone molecule can trigger the synthesis of many enzyme molecules. SMALL STIMULUS PRODUCES LARGE EFFECT. circulating concentrations are very low.
Term
Hormone Interactions
(3 types)
Definition
Synergistic, permissive, antagonistic
Term
Synergistic effect
Definition
multiple hormones act together for a greater effect.
-- synergism btwn FSH and testosterone and sperm levels.
Term
Permissive Effects
Definition
one hormone enhances the target organs response to a second later hormone.
--estrogen prepares uterus for action of progetsterone.
Term
antagonistic effect
Definition
one hormone opposes the action of another.
--insulin lowers blood glucose and glycogen raises it.
Term
Hormone Clearance
Definition
Hormones must be turned off when they have served their purpose. most are taken up and degraded by liver and kidney (bile or urine)
Term
Metabolic Clearance Rate (MCR)
Definition
rate of hormone removal from the blood.
Term
Half Life
Definition
time required to clear 50% of hormone from blood.
faster MCR the shorter the half life.
Term
Nervous V Endocrine
-internal communication-
Definition
nervous-electrical and chemical
endocrine- only chemical
Term
Nervous V.Endocrine
-persistence of response-
Definition
nervous-reacts quickly (1-10ms) stops quickly.
Endocrine-reacts slowly(sec-days)effects may continue for weeks
Term
Nervous V. Endocrine
-long term stimuli-
Definition
nervous- response declines (adapts quickly)
endocrine- response persists (adapts slowly)
Term
Nervous V. Endocrine
-area of effect-
Definition
nervous- targeted and specific (one organ)
endocrine- gerneral widespread effect (many organs)
Term
Nervous+Endocrine (5 sim)
Definition
1. several chemicals function as both hormones and neruotransmitters(norepine, cholecystokinin, TRH, dopamine, ADH)
2. Some hormones secreted by neurons that release their secretions into the blood stream( oxytocin and catecholamines)
3. Both systems have overlapping effects on same target cells ( norepin and glucagon, causes glycogen hydrolysis in liver)
4. systems regulate each other
5.both require receptors
Term
Hypothalamus
Definition
-shaped like a flattened funnel
-forms floor and walls of third ventricle of the brain
-regulates primitive functions of the body, water balance, thermoregulation, sex drive, and childbirth
-main function is homeostasis and is carried out by the pituitary gland
Term
Pituitary Gland
Definition
housed in the sella turcica or sphenoid bone. size and shape of a kidney bean
Term
Infundibulum
Definition
stalk that suspends the pituitary
Term
Adenohypophysis
Definition
Anterior. Arises from hypophyseal pouch. 3/4th of pituitary. anterior lobe,
Term
neurohypophysis
Definition
posterior. downgrowth from brain
Term
pars tuberalis
Definition
small mass of cells adhering to stalk
Term
Hypophyseal portal system
Definition
links A. pit to the hypothalamus.
-capilaries in hypothalamus connected to secondary capillaries in adenohypophysis by portal venules
-hypothalamis hormone regulate adenohypophysis cells
Term
3 parts of neruohypophysis
Definition
median, eminence, infundibulum and the posterior lobe(pars nervousa)
Term
Hypothalamo-hypophyseal tract
Definition
nerve tissue. nerve cell bodies in hypothalamus pass down the stalk to the tract and end in the posterior lobe. hypothalamis neruons secrete hormones that are stored in neurohypophysis until released into blood
Term
6 Hormones that regulate A. Pit
Definition
produced in the Hypothalamus
-thyrotropin-releasing hormone
-corticotropin-releasing hormone
-gonadotropin-releasing hormone
-growth hormone-releasing hormone
-prolactin-inhibiting hormone
-somatostatin
Term
2 hormones released into P. Pit
Definition
produced in hypothalamus
-oxytocin
-ADH
Term
Hypothalamic Hormones
Definition
Releasing if the stimulate pituitary cells and inhibiting hormones if they inhibit secretion
Term
releasing hormones
Definition
TRH, CRH, GnRH, GHRH. They affect a. pit secretion of TSH, PRL, ACTH, FSh, LH, GH
Term
inhibiting hormone
Definition
PIH inhibits secretion of prolactin and somatostatin which inhibits secretion of growth hormone by a. pit.
Term
oxytocin
Definition
stored and released by p.pit(not synthesized there)
-right and left paraventricular nuclei produces oxytocin (OT)
Term
ADH
Definition
stored and released by p. pit. (not synthesized there)
-supraoptic nuclei produce antidiuretic hormone.
Term
2 gonadotropin hormones synthesixed and secreted by a. lobe of pituitary
Definition
--target gonads
1. FSH (follicle stimulating hormone) stimulates secretion of ovarian sec hormones, developement of ovarian follicles and sperm production
2. LH ( luteinizing hormones) stimulates ovulation, stimulates corpus luteum to secrete progesterone, stimulates testes to secrete testosterone.
Term
4 other hormones synthesized and secreted by a. lobe pituitary
Definition
1.TSH-stimulates secretion of thyroid hormone
2.ACTH(adrenocoricotropic) stimulates adrenal cortex to secrete glucocorticoids
3. PRL (prolactin) after birth stimulates mammary glands to synthesize milk, enhances secretion of testosterone
4. Growth Hormone- stimulates mitosis and cellular differentiation
Term
Growth Hormone
Definition
-Widespread Effects on the body tissues, esp. cartilage bone muscle and fat.
Term
growth hormone and inducing liver to produce growth stimulants
Definition
1.stimulate target cells in diverse tisue
2.protein synthesis increases
3.lipid metabolism increased
4.carbohydrate metabolism: glucose sparing effect
5. electrolyte balance
Term
Growth Hormone
Definition
Bone growth, secreted during first 2 hrs of sleep. can peak in response to vigorous exercise, gradually decline with age.
Term
Antidiuretic Hormone
Definition
produced in the hypothalamus trasported by hypothalamo-hypophyseal tract to posterior lobe.
-increases water retention thus reducing urin volume and prevents dehydration. Also called vasopressin because it can cause vasoconstriction
Term
Oxytocin
Definition
produce in hypothalamus, transported by hypothalamo-hypophyseal tract.
-released during sexual arousal,and orgasm
-promotes feelings of sexual satisfaction and emotional bonding.
-stimulates labor contractions
-stimulates flow of milk during lactation
-promotes bonding btwn mother and child.
Term
pineal gland
Definition
attached to the roof of the 3rd ventricle. after age 7 it undergoes involution(shrinkage)
SAD(seasonal affective disorder)winter. depression. 2-3 hrs of bright light exposure each day releases melatonin
Term
thymus
Definition
plays role in endocrine lymphatic, and immune
bilobed. site of maturation of t cells important in immune defense.
secretes thymopoietin, thymosin, and thymulin that stimulate the developement of other lymphatic organs
Term
thyroid gland
Definition
largest endocrine gland
Term
Follicular Cells
Definition
secrete thyroxin(t4) and triiodothyronine(t3) which increase metabolic rate, o2 consumption, heat production, appetie, growth hormone, secretion, alertness and reflexes
Term
Parafollicular Cells
Definition
secrete calcitonin(lowers blood calciu, levels) in response to rising blood calcium. And stimulates osteoblast activity.
Term
Parathyroid gland
Definition
four glands. secrete parathyroid hormone
Term
Parathyroid hormone
Definition
increases blood calcium levels. promotes synthesis of calcitriol, increased absorption of calcium, decreases urinary excretion, increases bone resorption
Term
Adrenal Gland
Definition
small gland that sits atop each kidney. retroperitoneal like the kidney.
Adrenal Cortext and medulla formed by merger of two fetal glands with different origins and functions.
Term
Adrenal Medulla
Definition
Dual nature as endocrine and sympathetic ganglion of the nervous system.
-innervated by sympathetic preganglionic fibers.
Term
Chromaffin Cells
Definition
modified sympathetic postganglionic neurons. Make up the Adrenal Medulla
Term
Catecholamines
Definition
released by adrenal medulla.
norepinephrine and epinephrine has a trace of dopamine directly into bloodstream
Term
Effects of adrenal medulla
Definition
last longer than neurotransmitters. increase alertness and prepare body for physical activity.
-increase blood pressure, heart rate blood flow to muscles and metabolic rate.
-decreases digestion and urine production
Term
glycogenolysis and gluconeogenesis
Definition
boost glucose levels.
Term
glucose sparing effect
Definition
inhibits insulin secretion. muscles use fatty acids, saving glucose for brain.
Term
Adrenal Cortex
Definition
produces 25 steroids...corticosteroids and corticoids.
5 major steroid from 3 layers (zona glomerulosa, zona fasciculata, zon'a reticularis)
Term
Zona Glomerulosa
Definition
thin outer layer. cells are arranged in cluseters, secret mineralocorticoid (regulate electrolyte balance)
Term
Zona fasciculata
Definition
Thick middle layer. cells arranged in fasicles separtated by capillaries. secretes glucocorticoids.
Term
Zona Reticularis
Definition
Narrow inner layer. cells in branching network. secrete sex sterioids
Term
Mineralocorticoids
Definition
z.glomerulosa. electrolyte balance.
ex: Aldosterone stimulates sodium retention and potassium excretion water is retained with sodium by osmosis so blood volume and blood pressure are maintained.
Term
Glucocorticoids
Definition
z.fasiculata. regulates metabolism of glucose and other fuels, esp cortisol(stimulates fat and protein catabolism), gluconeogenesis(glucose from amino acids and fatty acids)and release of fatty acides and glucose into blood. Helps body adapt to stress and repair tissues. Anti inglammatory effect becomes immune supppression with long term use.
Term
sex steriods
Definition
z.reticularis. Androgens and estradiol.
Term
androgens
Definition
sets libido throughout life, large rold in prenatal male development(DHEA dehydroepiandrosterone) which other tissues convert to testosterone.
Term
estradiol
Definition
small quantity but important after menopause for sustaining adult bone mass, fat converts androgen into estrogen
Term
The pancreas
Definition
endocrine(pancreatic islets) and exocrine gland(acinar cells)
Term
Pancreatic Islets
Definition
secrete hormones like insulin, glucagon, somatostatin directly into bloodstream. consists of alpha cells, betha cells, delta cells pp cells and g cells
Term
acinar cells
Definition
secrete pancreatic juices into pancreatic duct which joins with the bild duct and empties into the duodenum
Term
glucagon
Definition
Alpha cells. released btwn meals when blood glucose is falling.
-in liver raises blood glucose level.
-in adipose tissue stimulates fat catabolism
-released when amino acid levels in blood rise to promote acid absorption
Term
insulin
Definition
beta cells. secreted during and after meals. stimulates cells to absorb nutrients and store or metabolize them LOWERS BLOOD GLUCOSE LEVLES
Term
Diabetes mellitus type 1
Definition
insulin dependent. inadequate production of insulin
Term
diabetes mellitus type 2
Definition
non-insulin dependent. inadequate activity at the insulin receptor
Term
Somatostatin
Definition
Delta cells. partially suppresses secretion of glucagon and insulin. in A. pit inhibits secretion of growth hormone releasing hormone and TSH
Term
Pancreatic Polypeptide
Definition
PP or F cells. inhibits gallbladder and intestinal contractions and secretion of stomach acid and pancreatic digestive enzymes
Term
gastrin
Definition
G cells. stimulates secretion of gastric acid(HCI) by the parietal cells of the stomach and aids in gastric motility and emptying
Term
hyperglycemic hormones
Definition
raise blood glucose concentrations.
ex:glucagon, GH, epinephrine, norepeinepherine, cortisol, corticosterone
Term
hypoglycemic hormones
Definition
lower blood glucose
ex:insulin
Term
Gonads
Definition
ovaries and testes both endocrine and exocrine
Term
gonads exocrine
Definition
produce whole cells (egg and sperm) cytogenic glands
Term
gonads endocrine
Definition
produce gonadal hormones...mostly steroids.
Term
ovarian hormones
Definition
estradiol, progesterone and inhibin
Term
testicular hormones
Definition
testosteron, weaker androgens, estrogen, and inhibin
Term
follicle
Definition
egg surrounded by granulosa cells and capsule (theca)
Term
theca cells
Definition
synthesize andostenedione and converted to mainly estradiol
Term
seminiferous tubules
Definition
produce sperm.
tubule walls contain sustentacular cells
leydig cells lie in clusters
Term
testosterone
Definition
stimulates development of male reproductive system in fetus and adolescent and sex drive. sustain sperm production
Term
inhibin
Definition
from sustentacular cells. limits FSH secretion in order to regulate sperm prodcution
Term
Endocrine functions in the skin
Definition
keratinocytes convert a cholesterol-like steroid into cholecalciferol using uv from the sun
Term
endorcrine functions in the liver
Definition
involved in the production of at least five hormones.
Term
Endocrine functions in kidneys
Definition
plays role in production of 3 hormones.
calcitriol, renin, erythropoietin
Term
Endocrine functions in the heart
Definition
cardiac muscles secrete atrial and brain natriuretic peptieds. (ANP and BNP)
Term
Antrial and Brain Natriuretic peptides
Definition
decrease blood volume and blood pressure by increasing sodium and water output by kidneys
Term
Endocrine functions in stomach and small intetines
Definition
secrete at least 10 enteric hormones secreted by enteroendocrine cells. coordinate digestive motility and glandular secretion
Term
Leptin
Definition
secreted by adipose tissue.. slows appetite
Term
Osteocalcin
Definition
in osseous tissue, secreted by osteoblasts. inhibits weight gain and onset of type 2 diabetes mellitus.
Term
Placenta
Definition
secrete estrogen progesterone and others. regulated pregnancy and stimulates development of fetus and mammary glands
Term
Hydrophilic
Definition
mix easily with blood plasma. monoamines and peptides
Term
hydrophobic
Definition
steroids and thyroid hormone. binds to transport proteins
Term
Bound hormones
Definition
have longer half-life. Protected from liver enzymes and kidney filtration
Term
unbound hormone
Definition
leaves capillaries to reach target cell.
Term
Hydrophobic hormones
Definition
penetrate plasma membrane and enter nucleus. takes several hours to days to show effects due to lag for protein synthesis.
Term
hydrophilic hormones
Definition
cannot penetrate into target cells. must stimulate physiology indirectly
Term
Thyroid Hormone
(Thyroxine)
Definition
enters target cell by diffusion mostly as T4... then its converted into more potent T3. T3 then enters target cells and binds to receptors in DNA. Activates genes
Term
Stress
Definition
caused by any situation that upsets homeostasis and threatens ones physical or emotional well being.
Term
General Adaptation Syndrome
(GAS)
Definition
consistent way the body reacts to stress; typically involves elevated levels of epinephrine aand glucocorticoids
Term
Three stages of GAS
Definition
alarm reaction
stage of resistence
stage of exhaustion
Term
Alarm Reaction
Definition
initial response, prepares body for figh or flight. stored glycogen is consumed
Term
the stage of resistence
Definition
after a few hours glycogen reserves gone. but brain still needs glucose if situation had not been resolved.
stage dominated by cortisol
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