IBSS 1540 Exam 1 Questions with Correct Answers 100% Verified By Experts| Latest Update
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In Addison's disease, when the adrenal cortex is unresponsive to ACTH and little cortisol is
produced, what occurs int he feedback loop? low levels of cortisol increase production of
CRH in the hypothalamus and ACTH in the pituitary, but they still have no effect on the amount
of cortisol produced
In Cushing's disease, when an adenoma in the pituitary causes a high level of ACTH secretion,
what would you expect to occur in the feedback loop? the high amount of ACTH produced
causes a lot of cortisol to be synthesized in the adrenal cortex. This high cortisol feeds back to
the hypothalamus, causing decreased levels of CRH, and to the pituitary. However, the pituitary
does not respond and high levels of ACTH persist
In Cushing's syndrome, when a tumor in the adrenal Cortex causes cortisol secretion to be high,
what would you expect to occur in the feedback loop? the high levels of cortisol feedback to
both the hypothalamus and pituitary, causing secretion of CRH and ACTH to both decrease.
HOwvere, this has little effect on the adrenal cortex and high levels of cortisol persist
What would you expect to occur in the cortisol fedcoback regulation in an individual taking
exogenous glucocorticoids? the exogneous administration of the corticosteroids feedback to
both the hypothalamus and pituitary, decreasing secretion of CRH and ACTH. This causes the
adrenal cortex's secretion of cortisol to decrease
What is the role of the sympathetic nervous system in the secretion of catecholamines? it
promotes secretion of these hormones
Which cells of the adrenal gland synthesize catecholamines? the chromaffin cells
What is the role of thyroid hormone in the adrenal synthesis of catecholamines? they
catalyze the rate limiting step, converting the tyrosine precursor into DOPA
,What steps of catecholamine synthesis are highly regulated by sympathetic stimulation via
acetylcholine? the conversion of tyrosine to DOPA as well as the conversion of dopamine
into norepinephrine
What is the role of cortisol in the synthesis of catecholamines? cortisol regulates the
enzyme PNMT, which converts norepinephrine into epnephrine
What are the intermediates in the order they are synthesized in the formation of
catecholamines? tyrosine, DOPA, dopamine, NE, epi
What is the initial substrate for the biosynthesis of catecholamines? tyrosine
What are the two catecholamines? epinephrine and norepinephrine
What happens to DOPA during the synthesis of catecholamines? it is transported from the
cytoplasm into a granule of a chromaffin cell in order for dopamine hydroxylase enzyme to
convert it into norepinephrine
What occurs during the conversion of norepinephrine into epinephrine? the norepinephrine
re-enters the cytoplasm from the granule and is acted on by PNMT in order to form
epinephrine
What are the two types of chromaffin cells in the adrenal medulla? there are cells that make
epinephrine and those that make NE. one cell cannot make both
Which cells in the adrenal medulla contain PNMT? only those that synthesize epinephrine,
which is 80% of the cell population
What is the rate-limiting step in the synthesis of catecholamines? the first step, in which
tyrosine is converted to DOPA via TH
,What kind of feedback regulates catecholamine synthesis? negative feedback in which
increased concentrations of NE or epic inhibit the rate limiting enzyme
What is the effect of increased cortisol on catecholamine synthesis? it activates PNMT
enzymes and stimulates epinephrine synthesis
What happens to the catecholamines synthesized in the adrenal gland? they are stored
inside of granules in order to protect them from oxidation
What kind of receptors do catecholamines interact with? they can interact with various
different adrenergic receptors, each with a different effect on the body
What is the effect of epinephrine on glucose levels? it keeps blood glucose levels within the
appropriate range during exercise or stress
What is the effect of epinephrine on skeletal muscle? it triggers the breakdown of glycogen
into lactate, which is sent to the liver in order to form glucose
What is the effect of epinrphein on glucose? it stimulates the breakdown of glycogen into
glucose
What ist he effect of epinephrine on the pancreas? it increases glucagon secretion, and
decreases insulin secretion
What is the effect of epinephrine on adipose tissue? it breaks down triglycerides into fatty
acids, which then are utilized by the liver to make ketones
What is the effect of epinephrine on plasma glucose? it raises it
, What is the effect of epinephrine on gluconeogenesis? it stimulates it
What is the relationship between epinephrine and insulin? epinephrine is an insulin
antagonist, decrease the entry of glucose into insulin-dependent tissues
What ist he effect of epinephrine on plasma fatty acids? it increases lipolysis, forming fatty
acids that can eventually be used to synthesize ketones
Which three enzymes work together in order to degrade catecholamines? MAO, AO, and
COMT
What are the two main enzymes involved in the degradation of catecholamines? MAO and
COMT
How is norepinephrine removed from having its action on nervous system tissue? NE
released from the axon is recaptured into he cell by uptake-1, where it is either recycled or
broken down by MAO
Which transporter terminates NE in nervous tissue? Uptake -1
What are two examples of drugs that inhibit the action of uptake -1 in the nervous system, and
thereby have impaired ability to terminate the action of NE? cocaine and tricyclic
antidepressants
How is epinephrine terminated in non-nervous tissues? it dissolves out of the blood an
either diffuses away, binds adrenergic receptors on a target cell, or is taken up by the target cell
by uptake 2
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In Addison's disease, when the adrenal cortex is unresponsive to ACTH and little cortisol is
produced, what occurs int he feedback loop? low levels of cortisol increase production of
CRH in the hypothalamus and ACTH in the pituitary, but they still have no effect on the amount
of cortisol produced
In Cushing's disease, when an adenoma in the pituitary causes a high level of ACTH secretion,
what would you expect to occur in the feedback loop? the high amount of ACTH produced
causes a lot of cortisol to be synthesized in the adrenal cortex. This high cortisol feeds back to
the hypothalamus, causing decreased levels of CRH, and to the pituitary. However, the pituitary
does not respond and high levels of ACTH persist
In Cushing's syndrome, when a tumor in the adrenal Cortex causes cortisol secretion to be high,
what would you expect to occur in the feedback loop? the high levels of cortisol feedback to
both the hypothalamus and pituitary, causing secretion of CRH and ACTH to both decrease.
HOwvere, this has little effect on the adrenal cortex and high levels of cortisol persist
What would you expect to occur in the cortisol fedcoback regulation in an individual taking
exogenous glucocorticoids? the exogneous administration of the corticosteroids feedback to
both the hypothalamus and pituitary, decreasing secretion of CRH and ACTH. This causes the
adrenal cortex's secretion of cortisol to decrease
What is the role of the sympathetic nervous system in the secretion of catecholamines? it
promotes secretion of these hormones
Which cells of the adrenal gland synthesize catecholamines? the chromaffin cells
What is the role of thyroid hormone in the adrenal synthesis of catecholamines? they
catalyze the rate limiting step, converting the tyrosine precursor into DOPA
,What steps of catecholamine synthesis are highly regulated by sympathetic stimulation via
acetylcholine? the conversion of tyrosine to DOPA as well as the conversion of dopamine
into norepinephrine
What is the role of cortisol in the synthesis of catecholamines? cortisol regulates the
enzyme PNMT, which converts norepinephrine into epnephrine
What are the intermediates in the order they are synthesized in the formation of
catecholamines? tyrosine, DOPA, dopamine, NE, epi
What is the initial substrate for the biosynthesis of catecholamines? tyrosine
What are the two catecholamines? epinephrine and norepinephrine
What happens to DOPA during the synthesis of catecholamines? it is transported from the
cytoplasm into a granule of a chromaffin cell in order for dopamine hydroxylase enzyme to
convert it into norepinephrine
What occurs during the conversion of norepinephrine into epinephrine? the norepinephrine
re-enters the cytoplasm from the granule and is acted on by PNMT in order to form
epinephrine
What are the two types of chromaffin cells in the adrenal medulla? there are cells that make
epinephrine and those that make NE. one cell cannot make both
Which cells in the adrenal medulla contain PNMT? only those that synthesize epinephrine,
which is 80% of the cell population
What is the rate-limiting step in the synthesis of catecholamines? the first step, in which
tyrosine is converted to DOPA via TH
,What kind of feedback regulates catecholamine synthesis? negative feedback in which
increased concentrations of NE or epic inhibit the rate limiting enzyme
What is the effect of increased cortisol on catecholamine synthesis? it activates PNMT
enzymes and stimulates epinephrine synthesis
What happens to the catecholamines synthesized in the adrenal gland? they are stored
inside of granules in order to protect them from oxidation
What kind of receptors do catecholamines interact with? they can interact with various
different adrenergic receptors, each with a different effect on the body
What is the effect of epinephrine on glucose levels? it keeps blood glucose levels within the
appropriate range during exercise or stress
What is the effect of epinephrine on skeletal muscle? it triggers the breakdown of glycogen
into lactate, which is sent to the liver in order to form glucose
What is the effect of epinrphein on glucose? it stimulates the breakdown of glycogen into
glucose
What ist he effect of epinephrine on the pancreas? it increases glucagon secretion, and
decreases insulin secretion
What is the effect of epinephrine on adipose tissue? it breaks down triglycerides into fatty
acids, which then are utilized by the liver to make ketones
What is the effect of epinephrine on plasma glucose? it raises it
, What is the effect of epinephrine on gluconeogenesis? it stimulates it
What is the relationship between epinephrine and insulin? epinephrine is an insulin
antagonist, decrease the entry of glucose into insulin-dependent tissues
What ist he effect of epinephrine on plasma fatty acids? it increases lipolysis, forming fatty
acids that can eventually be used to synthesize ketones
Which three enzymes work together in order to degrade catecholamines? MAO, AO, and
COMT
What are the two main enzymes involved in the degradation of catecholamines? MAO and
COMT
How is norepinephrine removed from having its action on nervous system tissue? NE
released from the axon is recaptured into he cell by uptake-1, where it is either recycled or
broken down by MAO
Which transporter terminates NE in nervous tissue? Uptake -1
What are two examples of drugs that inhibit the action of uptake -1 in the nervous system, and
thereby have impaired ability to terminate the action of NE? cocaine and tricyclic
antidepressants
How is epinephrine terminated in non-nervous tissues? it dissolves out of the blood an
either diffuses away, binds adrenergic receptors on a target cell, or is taken up by the target cell
by uptake 2
