THE ENDOCRINE SYSTEM –
QUESTIONS AND ANSWERS
In which ways are the actions of PTH and calcitriol similar and different? - ANSWER-
similarity: both increase blood calcium ion levels: differences: PTH increases number
and activity of osteoclasts, slows the rate of calcium ion loss from blood into urine,
and stimulates the kidneys to produce calcitriol, whereas calcitriol acts on the GI
tract to increase the rate of calcium ion absorption from food into the blood
What is the benefit of adding vitamin D to various food products such as milk?
What is the benefit of adding vitamin D to various food products such as milk?
What is the benefit of adding vitamin D to various food products such as milk?
What is the benefit of adding vitamin D to various food products such as milk? -
ANSWER-calcitriol is the active form of vitamin D and increases calcium absorption
through the GI tract
Would hypopituitarism affect calcium balance in the body? - ANSWER-yes, because
lack of growth hormone would make it harder to utilize the calcium in the body to
build bones
In which two ways can angiotensin II increase blood pressure? What are its target
tissues for each mechanism? - ANSWER-stimulates contraction of smooth muscle in
the walls of arterioles and stimulates the adrenal cortex to secrete aldosterone;
arterioles and adrenal gland
Which stimulus initiates the renin-angiotensin-aldosterone pathway? Which stimulus
turns the pathway off? Is this a negative or positive feedback loop? - ANSWER-(a)
dehydration, low blood sodium or hemorrhage;
(b) increase in blood pressure;
(c) negative
How do the hypothalamus and anterior pituitary influence glucocorticoid secretion? -
ANSWER-hypothalamus produces CRH which targets the anterior pituitary to
produce ACTH which targets the adrenal cortex to produce glucocorticoids
How do glucocorticoids influence ATP production? How does this influence your
resistance to stress? - ANSWER-(a) gluconeogenesis and triglyceride breakdown to
stimulate ATP production;
(b) additional fuel for ATP production allows the body to combat a range of stressors
Which chemicals do the adrenal medulla and the autonomic nervous system both
produce? - ANSWER-norepinephrine and epinephrine
Why is cyclic AMP considered a "second messenger"? - ANSWER-it activates
inactive enzymes in the cell to give the response attributed to the hormone
, What factors determine the responsiveness of a target cell to a hormone? -
ANSWER-hormone concentration, abundance of target cell's hormone receptors,
influence exerted by other hormones
What are the three influences over hormone secretion? - ANSWER-signals from the
nervous system, chemical changes in the blood, other hormones
What is the functional importance of the hypophyseal portal veins? - ANSWER-they
are the direct route taken by hypothalamic hormones to act immediately on anterior
pituitary cells, before the hormones are diluted or destroyed in the general circulation
Which anterior pituitary hormones stimulate a second endocrine gland to release a
hormone? - ANSWER-FSH, LH, TSH, ACTH
You have noticed your neighbor's 8-year-old child is the same height as her 5-year-
old cousin. This child could be deficient in which hormone? - ANSWER-hGH
If a person has a pituitary tumor that secretes a large amount of hGH and the tumor
cells are not responsive to regulation by GHRH and GHIH, will hyperglycemia or
hypoglycemia be more likely? Explain your answer. - ANSWER-Hypoglycemia
Explain how blood levels of T3/T4, TSH, and TRH would change in a laboratory
animal that has undergone a thyroidectomy (complete removal of its thyroid gland). -
ANSWER-low blood levels of T3 and T4 would stimulate increase in levels of TRH,
which would stimulate increased levels of TSH; however, removal of the thyroid
gland would prevent production of T3 and T4
Where are the hormones secreted by the posterior pituitary produced? How do OT
and ADH get from their production site to the capillaries of the posterior pituitary? -
ANSWER-(a) hypothalamic neurosecretory cells;
(b) they are packed into vesicles and transported down the axons to the axon
terminals in the posterior pituitary until exocytosis is triggered, then the hormones
are released and diffuse into the capillaries of the posterior pituitary
Functionally, how are the axons of hypothalamic neurosecretory cells and the
hypophyseal portal veins similar? - ANSWER-both are direct routes for hormone
release that do not involve the general circulation
Is OT regulated by positive or negative feedback? What feedback stimuli influence
the release of OT? - ANSWER-(a) positive feedback;
(b) stretching of the cervix and suckling
Sometimes during difficult deliveries or following long labor a synthetic form of
oxytocin is given to the mother. Why? - ANSWER-to increase OT production and
uterine contractions for childbirth
What effect would drinking a large volume of water have on the osmotic pressure of
your blood? The level of ADH? - ANSWER-(a) lower osmotic pressure;
(b) decrease level of ADH
QUESTIONS AND ANSWERS
In which ways are the actions of PTH and calcitriol similar and different? - ANSWER-
similarity: both increase blood calcium ion levels: differences: PTH increases number
and activity of osteoclasts, slows the rate of calcium ion loss from blood into urine,
and stimulates the kidneys to produce calcitriol, whereas calcitriol acts on the GI
tract to increase the rate of calcium ion absorption from food into the blood
What is the benefit of adding vitamin D to various food products such as milk?
What is the benefit of adding vitamin D to various food products such as milk?
What is the benefit of adding vitamin D to various food products such as milk?
What is the benefit of adding vitamin D to various food products such as milk? -
ANSWER-calcitriol is the active form of vitamin D and increases calcium absorption
through the GI tract
Would hypopituitarism affect calcium balance in the body? - ANSWER-yes, because
lack of growth hormone would make it harder to utilize the calcium in the body to
build bones
In which two ways can angiotensin II increase blood pressure? What are its target
tissues for each mechanism? - ANSWER-stimulates contraction of smooth muscle in
the walls of arterioles and stimulates the adrenal cortex to secrete aldosterone;
arterioles and adrenal gland
Which stimulus initiates the renin-angiotensin-aldosterone pathway? Which stimulus
turns the pathway off? Is this a negative or positive feedback loop? - ANSWER-(a)
dehydration, low blood sodium or hemorrhage;
(b) increase in blood pressure;
(c) negative
How do the hypothalamus and anterior pituitary influence glucocorticoid secretion? -
ANSWER-hypothalamus produces CRH which targets the anterior pituitary to
produce ACTH which targets the adrenal cortex to produce glucocorticoids
How do glucocorticoids influence ATP production? How does this influence your
resistance to stress? - ANSWER-(a) gluconeogenesis and triglyceride breakdown to
stimulate ATP production;
(b) additional fuel for ATP production allows the body to combat a range of stressors
Which chemicals do the adrenal medulla and the autonomic nervous system both
produce? - ANSWER-norepinephrine and epinephrine
Why is cyclic AMP considered a "second messenger"? - ANSWER-it activates
inactive enzymes in the cell to give the response attributed to the hormone
, What factors determine the responsiveness of a target cell to a hormone? -
ANSWER-hormone concentration, abundance of target cell's hormone receptors,
influence exerted by other hormones
What are the three influences over hormone secretion? - ANSWER-signals from the
nervous system, chemical changes in the blood, other hormones
What is the functional importance of the hypophyseal portal veins? - ANSWER-they
are the direct route taken by hypothalamic hormones to act immediately on anterior
pituitary cells, before the hormones are diluted or destroyed in the general circulation
Which anterior pituitary hormones stimulate a second endocrine gland to release a
hormone? - ANSWER-FSH, LH, TSH, ACTH
You have noticed your neighbor's 8-year-old child is the same height as her 5-year-
old cousin. This child could be deficient in which hormone? - ANSWER-hGH
If a person has a pituitary tumor that secretes a large amount of hGH and the tumor
cells are not responsive to regulation by GHRH and GHIH, will hyperglycemia or
hypoglycemia be more likely? Explain your answer. - ANSWER-Hypoglycemia
Explain how blood levels of T3/T4, TSH, and TRH would change in a laboratory
animal that has undergone a thyroidectomy (complete removal of its thyroid gland). -
ANSWER-low blood levels of T3 and T4 would stimulate increase in levels of TRH,
which would stimulate increased levels of TSH; however, removal of the thyroid
gland would prevent production of T3 and T4
Where are the hormones secreted by the posterior pituitary produced? How do OT
and ADH get from their production site to the capillaries of the posterior pituitary? -
ANSWER-(a) hypothalamic neurosecretory cells;
(b) they are packed into vesicles and transported down the axons to the axon
terminals in the posterior pituitary until exocytosis is triggered, then the hormones
are released and diffuse into the capillaries of the posterior pituitary
Functionally, how are the axons of hypothalamic neurosecretory cells and the
hypophyseal portal veins similar? - ANSWER-both are direct routes for hormone
release that do not involve the general circulation
Is OT regulated by positive or negative feedback? What feedback stimuli influence
the release of OT? - ANSWER-(a) positive feedback;
(b) stretching of the cervix and suckling
Sometimes during difficult deliveries or following long labor a synthetic form of
oxytocin is given to the mother. Why? - ANSWER-to increase OT production and
uterine contractions for childbirth
What effect would drinking a large volume of water have on the osmotic pressure of
your blood? The level of ADH? - ANSWER-(a) lower osmotic pressure;
(b) decrease level of ADH
