the endocrine system exam practice
questions with complete solutions
what is down-regulation - ANSWER-number of recpetors is decreased. This can
occur when hormone levels have been high and the cell wants to reduce its
response to the hormone
what happens in a high affinity state - ANSWER-the receptor has a strong attraction
for the hormone (very good lock and key fit)
in a high affinity state the receptors are ______ efficient and _____ necessarily need
as much hormone for _____ activation. - ANSWER-very, do not, full
what happens in a low affinity state? - ANSWER-the receptor has a weak attraction
for the hormone (not a good lock and key fit)
in a low affinity state the receptors are ______ efficient and _____ need more
hormone for _____ activation. - ANSWER-less, may, full
if a hormone is ______ ______ it is transported free in blood; their target organ is
usually ______. - ANSWER-lipid insoluble (all other hormones); rapid
if a hormone is ______ ______ it is transported in blood attached to a protein; their
target organ effect takes ______. - ANSWER-lipid soluble (steroids and thyroid);
hours to days
what is a half life - ANSWER-the length of time it takes for the level of a hormone to
decrease by half in the blood
which hormones have the shortest half-life - ANSWER-lipid insoluble (amino acid
based)
what kind of interaction of hormones is it when there must be more than one
hormone present for full target cell response? Ex. GH and TH both must be present
for normal bone growth and development - ANSWER-permissiveness
what kind of interaction of hormones is it when more than one hromone produces the
same effects but together their effect is much larger? Ex. glucagon and epinephrine
raise blood glucose but together they raise it much more. - ANSWER-synergism
what kind of interaction of hormones is it when one hormone opposes the action of
another? Ex. calcitonin lowers blood calcium and parathyroid hormone raises it -
ANSWER-antagonism
the pituitary gland is also called what? - ANSWER-hypophysis
, the posterior pituitary is ______ tissue and anterior is _______. - ANSWER-neural,
glandular
what is the main function of posterior pituitary? - ANSWER-hormone storage area,
releases meurohormones made in the hypothalamus (does not itself make
hormones)
how do neurohormones travel from hypothalamus to posterior pituitary? (4) -
ANSWER-1. hypothalamic neurons make oxytocin and ADH in the hypothalamus
2. hormones are trasnported down the axons of the hypothalamic-hypophyseal tract
to the posterior pituitary
3. hormones are stored in axon terminals of the posterior pituitary
4. action potentials cause the release of hormones into the blood
oxytocin is made in the _____ nucleus and ADH is made in _______ nucleus -
ANSWER-paraventricular, supraoptic
what is purpose of oxytocin - ANSWER-released in high amounts during childbirth
and nursing mothers
stimulates uterine contractions and milk ejection
both actions are a result of positive feedbacks mechanisms
what is purpose of ADH - ANSWER-stops urine production
osmoreceptors in hypothalamus montior blood
if blood becomes too concentrated (dehydration) what happens? - ANSWER--
osmoreceptors send impules to supraoptic nucleus
-ADH is synthesized and released
-ADH goes to kidney tubules and causes water to be reabsorbed and less urine is
produced
what are other triggers that release ADH? - ANSWER-pain, low BP, nicotine,
morphine
what is vasoconstriction? - ANSWER-when BP is very low ADH is released in large
amounts and binds to recpetors on vascular smooth muscle
ADH pathology - ANSWER-- alcohol inhibits ADH secretion causing an increase in
urine output
-diabetes insipidus (large urine output and intense thirst)
The hypophyseal portal system consists of - ANSWER-primary capillary plexus,
hypophyseal portal veins, secondary capillary plexus
what does The hypophyseal portal system do? - ANSWER-carries releasing and
inhibiting hormones to the adrenohyposis (anterior pituitary) to regulate hormone
secretion
what are the 6 major hormones of the anterior pituitary? which are trophic and
nontrophic? - ANSWER-Four are trophic- TSH, ACTH, FSH, LH
questions with complete solutions
what is down-regulation - ANSWER-number of recpetors is decreased. This can
occur when hormone levels have been high and the cell wants to reduce its
response to the hormone
what happens in a high affinity state - ANSWER-the receptor has a strong attraction
for the hormone (very good lock and key fit)
in a high affinity state the receptors are ______ efficient and _____ necessarily need
as much hormone for _____ activation. - ANSWER-very, do not, full
what happens in a low affinity state? - ANSWER-the receptor has a weak attraction
for the hormone (not a good lock and key fit)
in a low affinity state the receptors are ______ efficient and _____ need more
hormone for _____ activation. - ANSWER-less, may, full
if a hormone is ______ ______ it is transported free in blood; their target organ is
usually ______. - ANSWER-lipid insoluble (all other hormones); rapid
if a hormone is ______ ______ it is transported in blood attached to a protein; their
target organ effect takes ______. - ANSWER-lipid soluble (steroids and thyroid);
hours to days
what is a half life - ANSWER-the length of time it takes for the level of a hormone to
decrease by half in the blood
which hormones have the shortest half-life - ANSWER-lipid insoluble (amino acid
based)
what kind of interaction of hormones is it when there must be more than one
hormone present for full target cell response? Ex. GH and TH both must be present
for normal bone growth and development - ANSWER-permissiveness
what kind of interaction of hormones is it when more than one hromone produces the
same effects but together their effect is much larger? Ex. glucagon and epinephrine
raise blood glucose but together they raise it much more. - ANSWER-synergism
what kind of interaction of hormones is it when one hormone opposes the action of
another? Ex. calcitonin lowers blood calcium and parathyroid hormone raises it -
ANSWER-antagonism
the pituitary gland is also called what? - ANSWER-hypophysis
, the posterior pituitary is ______ tissue and anterior is _______. - ANSWER-neural,
glandular
what is the main function of posterior pituitary? - ANSWER-hormone storage area,
releases meurohormones made in the hypothalamus (does not itself make
hormones)
how do neurohormones travel from hypothalamus to posterior pituitary? (4) -
ANSWER-1. hypothalamic neurons make oxytocin and ADH in the hypothalamus
2. hormones are trasnported down the axons of the hypothalamic-hypophyseal tract
to the posterior pituitary
3. hormones are stored in axon terminals of the posterior pituitary
4. action potentials cause the release of hormones into the blood
oxytocin is made in the _____ nucleus and ADH is made in _______ nucleus -
ANSWER-paraventricular, supraoptic
what is purpose of oxytocin - ANSWER-released in high amounts during childbirth
and nursing mothers
stimulates uterine contractions and milk ejection
both actions are a result of positive feedbacks mechanisms
what is purpose of ADH - ANSWER-stops urine production
osmoreceptors in hypothalamus montior blood
if blood becomes too concentrated (dehydration) what happens? - ANSWER--
osmoreceptors send impules to supraoptic nucleus
-ADH is synthesized and released
-ADH goes to kidney tubules and causes water to be reabsorbed and less urine is
produced
what are other triggers that release ADH? - ANSWER-pain, low BP, nicotine,
morphine
what is vasoconstriction? - ANSWER-when BP is very low ADH is released in large
amounts and binds to recpetors on vascular smooth muscle
ADH pathology - ANSWER-- alcohol inhibits ADH secretion causing an increase in
urine output
-diabetes insipidus (large urine output and intense thirst)
The hypophyseal portal system consists of - ANSWER-primary capillary plexus,
hypophyseal portal veins, secondary capillary plexus
what does The hypophyseal portal system do? - ANSWER-carries releasing and
inhibiting hormones to the adrenohyposis (anterior pituitary) to regulate hormone
secretion
what are the 6 major hormones of the anterior pituitary? which are trophic and
nontrophic? - ANSWER-Four are trophic- TSH, ACTH, FSH, LH
