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Bio 669 Quiz 3 Questions And Answers With 100% Correct Answers Latest Update 2024/2025.
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Bio 669 Quiz 3 Questions And Answers With 100% Correct Answers Latest Update 2024/2025.
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Bio 669 Quiz 3 Questions And Answers With 100%Correct Answers Latest Update 2024/2025.
endocrine system - ANSWER differentiate reproductive & CNS in fetus
stimulate growth & development
coordinate male & female reproductive systems
maintain internal environments
adapt to emergency demands of the body
endocrine glands release - ANSWER hormones into the circulation which then trigger
intracellular responses
hormones have - ANSWER specific rates & rhythms of secretion (diurnal, cyclic, & pulsatile
patterns) that depend on levels of circulating substrates
-they affect only target cells w/specific receptors for the hormone then act on these cells
-are excreted by kidneys or metabolized by liver which inactivates them
hormones are released by - ANSWER chemical factors (glucose or calcium), endocrine factors
(hormone from 1 gland controlling another) & neural control
insulin secreted by chemical stimulation of increased glucose levels. cortisol from adrenal cortex is an
endocrine factor that regulates & stimulates insulin secretion & stimulation of insulin secreting cells of
pancreas by the ANS is a form of neural control
negative feedback - ANSWER a mechanism of response in which a stimulus initiates reactions
that reduce the stimulus
most common
occurs when a changing chemical, neural, or endocrine response to a stimulus decreases the synthesis
& secretion of a hormones
negative feedback example - ANSWER decreased levels of T3&T4 stimulates secretion of
thyrotropin releasing hormone which stimulates secretion of TSH. TSH stimulates secretion of T3&T4
increased levels of T3&T4 cause negative feedback on pituitary & hypothalamus to inhibit TSH & TSR
synthesis
positive feedback - ANSWER occurs when a neural, chemical, or endocrine response increases
the synthesis & secretion of a hormone
,positive feedback example - ANSWER increased levels of estradiol provides positive feedback
on anterior pituitary & hypothalamus causing an increase in GH & FSH
target cells - ANSWER have receptors for specific hormones
receptors of target cells recognize & bind w/high affinity to their particular hormones
the more receptors or the higher the affinity of the receptors, the more sensitive the cell to the
stimulating effects of a hormone
up regulation - ANSWER low concentrations of hormones increase the number of receptors
per cell
down regulation - ANSWER high concentrations of hormones decrease the number of
receptors
direct effects of hormones - ANSWER to target cells are the obvious changes in cell function
that result specifically from stimulation of a particular hormone
permissive effects of hormones - ANSWER are less obvious hormone induced changes that
facilitate the maximal response or functioning of a cell
water soluble hormones (peptides) - ANSWER -circulate in free/unbound forms
-short acting response
-high molecular weight & can't diffuse across cell membrane
-interact or bind w/receptors located in or on the cell membrane
fat soluble hormones - ANSWER -circulate bound to water soluble carrier or transport protein
-remain in blood for days
-can diffuse freely across the membrane
-bind w/cytosolic or nuclear receptors
1st messenger - ANSWER hormone bound to plasma membrane; never enters cell
ex-insulin, GH, prolactin
2nd messenger - ANSWER receptor interaction initiates a signal that generates a small
molecule inside the cell
, example-cAMP, calcium
fat/lipid soluble hormone - ANSWER steroids
synthesized from cholesterol
androgen, estrogen, glucocorticoids, vitamin D, retinoid, progestins
small lipophillic, hydrophobic molecules that cross the plasma membrane by simple diffusion
receptors are in the cytosol & nucleus
hypothalamic pituitary axis (HPA) - ANSWER forms the structural & functional basis for central
integration of neurologic & endocrine systems
produces several hormones
hypothalamus - ANSWER at base on brain
connected to anterior pituitary gland via the hypophysial blood vessels & to the posterior via a nerves
tract called the hypothalamohypophysial tract.
hypothalmic neurosecretory cells - ANSWER secrete hypothalmic releasing hormones that
regulate the release of hormones from the anterior pituitary & synthesize ADH & oxytocin from the
posterior pituitary
pituitary gland - ANSWER composed of 2 lobes: anterior & posterior
anterior pituitary - ANSWER 75% of gland
composed of 3 glands
-pars distalis-source of anterior pituitary hormones
-pars tuberalis-thin layer of cells on anterior & lateral portions of the pituitary stalk
-pars intermedia-lies b/w the 2 & secretes melanocyte-stimulating hormone in fetus
chromophobes - ANSWER non-secretory cells
chromophils - ANSWER secretory cells
tropic hormones - ANSWER hormones that stimulate other glands to release their hormones
melanocyte stimulating hormone - ANSWER produces melanin secretion which darkens skin
color
FSH & LH - ANSWER regulate processes in the gonads and the production of sex hormones
ACTH - ANSWER regulates cortisol
TSH - ANSWER released from anterior pituitary gland and causes thyroid gland to synthesize
thyroxine
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