1. Thyroid-stimulating hormone (TSH) is released to stimulate thyroid hormone (TH) and is
inhibited when plasma levels of TH are adequate. This is an example of:
a. Positive feedback
b. Neural regulation
c. Negative feedback
d. Physiologic regulation - ANSWER>>Negative feedback. Feedback systems provide precise
monitoring and control of the cellular environment. Negative feedback occurs because the
changing chemical, neural, or endocrine response to a stimulus negates the initiating change
that triggered the release of the hormone. Thyrotropin-releasing hormone (TRH) from the
hypothalamus stimulates TSH secretion from the anterior pituitary. Secretion of TSH
stimulates the synthesis and secretion of THs. Increasing levels of T4 and triiodothyronine (T3)
then generate negative feedback on the pituitary and hypothalamus to inhibit TRH and TSH
synthesis.
1. The releasing hormones that are made in the hypothalamus travel to the anterior pituitary
via the:
a. Vessels of the zona fasciculata
b. Hypophyseal stalk
c. Infundibular stem
d. Portal hypophyseal blood vessels
Portal hypophyseal blood vessels. - ANSWER>>Releasing and inhibitory hormones are
synthesized in the hypothalamus and are secreted into the portal blood vessels through
which they travel to the anterior pituitary hormones.
1. Which mineral is needed for thyroid-stimulating hormone (TSH) to stimulate the secretion of
thyroid hormone (TH)?
a. Iron
b. Iodide
,c. Zinc
d. Copper - ANSWER>>Iodide. TSH, which is synthesized and stored in the anterior pituitary,
stimulates secretion of TH by activating intracellular processes, including the uptake of iodine
necessary for the synthesis of TH.
1. Lipid-soluble hormone receptors are located:
a. Inside the plasma membrane in the cytoplasm
b. On the outer surface of the plasma membrane
c. Inside the mitochondria
d. On the inner surface of the plasma membrane - ANSWER>>Inside the plasma membrane in
the cytoplasm. Lipid-soluble hormone receptors are located inside the plasma membrane and
easily diffuse across the plasma membrane to bind to either cytosolic or nuclear receptors.
1. What effect does hyperphosphatemia have on other electrolytes?
a. Increases serum calcium
b. Decreases serum magnesium
c. Decreases serum calcium
d. Increases serum magnesium
Decreases serum calcium. - ANSWER>>Hyperphosphatemia leads to hypocalcemia. Remember
that phos and calcium are inversely related.
1. Insulin transports which electrolyte in the cell?
a. Potassium
b. Sodium
c. Calcium
,d. Phosphorus - ANSWER>>Potassium. Insulin facilitates the intracellular transport of
potassium, phosphate, and magnesium.
1. Which second messenger is stimulated by epinephrine binding to a β-adrenergic receptor?
a. Calcium
b. Inositol triphosphate (IP3)
c. Diacylglycerol (DAG)
d. Cyclic adenosine monophosphate (cAMP) - ANSWER>>Cyclic adenosine monophosphate
(cAMP). Second-messenger molecules are the initial link between the first signal (hormone)
and the inside of the cell. For example, the binding of epinephrine to a β adrenergic-receptor
subtype activates (through a stimulatory G protein) the enzyme, adenylyl cyclase. Adenylyl
cyclase catalyzes the conversion of adenosine triphosphate (ATP) to the second messenger, 3',
and 5'-cAMP.
1. Regulation of the release of catecholamines from the adrenal medulla is an example of which
type of regulation?
a. Negative feedback
b. Neural
c. Positive feedback
d. Physiologic - ANSWER>>Neural. The release of hormones occurs either in response to an
alteration in the cellular environment or in the process of maintaining a regulated level of
certain hormones or certain substances. Several different mechanisms, one of which is neural
control (e.g., stress-induced release of catecholamines from the adrenal medulla), regulate
the release of hormones.
1. Which hormone does the second messenger calcium (Ca++) bind to activate phospholipase C
through a G protein?
a. Angiotensin II
b. Estrogen
c. Thyroxine
, d. Testosterone - ANSWER>>Angiotensin II. Ca++ is considered an important second messenger
that facilitates the binding of a hormone (e.g., norepinephrine, angiotensin II) to a surface
receptor, activating the enzyme phospholipase C through a G protein inside the plasma
membrane.
1. The control of calcium in cells is important because it:
a. Is controlled by the calcium negative-feedback loop.
b. Is continuously synthesized.
c. Acts as a second messenger.
d. Carries lipid-soluble hormones in the bloodstream. - ANSWER>>Acts as a second messenger.
In addition to being an important ion that participates in a multitude of cellular actions, Ca++
is considered an important second messenger.
1. Where is antidiuretic hormone (ADH) synthesized, and where does it act?
a. Hypothalamus; renal tubular cells
b. Anterior pituitary; posterior pituitary
c. Renal tubules; renal collecting ducts
d. Posterior pituitary; loop of Henle - ANSWER>>Hypothalamus; renal tubular cells. Once
synthesized in the hypothalamus, ADH acts on the vasopressin 2 (V2) receptors of the renal
duct cells to increase their permeability.
1. How does a faulty negative-feedback mechanism result in a hormonal imbalance?
a. Hormones are not synthesized in response to cellular and tissue activities.
b. Decreased hormonal secretion is a response to rising hormone levels.
c. Too little hormone production is initiated.
d. Excessive hormone production results from a failure to turn off the system. -
ANSWER>>Excessive hormone production results from a failure to turn off the system.
inhibited when plasma levels of TH are adequate. This is an example of:
a. Positive feedback
b. Neural regulation
c. Negative feedback
d. Physiologic regulation - ANSWER>>Negative feedback. Feedback systems provide precise
monitoring and control of the cellular environment. Negative feedback occurs because the
changing chemical, neural, or endocrine response to a stimulus negates the initiating change
that triggered the release of the hormone. Thyrotropin-releasing hormone (TRH) from the
hypothalamus stimulates TSH secretion from the anterior pituitary. Secretion of TSH
stimulates the synthesis and secretion of THs. Increasing levels of T4 and triiodothyronine (T3)
then generate negative feedback on the pituitary and hypothalamus to inhibit TRH and TSH
synthesis.
1. The releasing hormones that are made in the hypothalamus travel to the anterior pituitary
via the:
a. Vessels of the zona fasciculata
b. Hypophyseal stalk
c. Infundibular stem
d. Portal hypophyseal blood vessels
Portal hypophyseal blood vessels. - ANSWER>>Releasing and inhibitory hormones are
synthesized in the hypothalamus and are secreted into the portal blood vessels through
which they travel to the anterior pituitary hormones.
1. Which mineral is needed for thyroid-stimulating hormone (TSH) to stimulate the secretion of
thyroid hormone (TH)?
a. Iron
b. Iodide
,c. Zinc
d. Copper - ANSWER>>Iodide. TSH, which is synthesized and stored in the anterior pituitary,
stimulates secretion of TH by activating intracellular processes, including the uptake of iodine
necessary for the synthesis of TH.
1. Lipid-soluble hormone receptors are located:
a. Inside the plasma membrane in the cytoplasm
b. On the outer surface of the plasma membrane
c. Inside the mitochondria
d. On the inner surface of the plasma membrane - ANSWER>>Inside the plasma membrane in
the cytoplasm. Lipid-soluble hormone receptors are located inside the plasma membrane and
easily diffuse across the plasma membrane to bind to either cytosolic or nuclear receptors.
1. What effect does hyperphosphatemia have on other electrolytes?
a. Increases serum calcium
b. Decreases serum magnesium
c. Decreases serum calcium
d. Increases serum magnesium
Decreases serum calcium. - ANSWER>>Hyperphosphatemia leads to hypocalcemia. Remember
that phos and calcium are inversely related.
1. Insulin transports which electrolyte in the cell?
a. Potassium
b. Sodium
c. Calcium
,d. Phosphorus - ANSWER>>Potassium. Insulin facilitates the intracellular transport of
potassium, phosphate, and magnesium.
1. Which second messenger is stimulated by epinephrine binding to a β-adrenergic receptor?
a. Calcium
b. Inositol triphosphate (IP3)
c. Diacylglycerol (DAG)
d. Cyclic adenosine monophosphate (cAMP) - ANSWER>>Cyclic adenosine monophosphate
(cAMP). Second-messenger molecules are the initial link between the first signal (hormone)
and the inside of the cell. For example, the binding of epinephrine to a β adrenergic-receptor
subtype activates (through a stimulatory G protein) the enzyme, adenylyl cyclase. Adenylyl
cyclase catalyzes the conversion of adenosine triphosphate (ATP) to the second messenger, 3',
and 5'-cAMP.
1. Regulation of the release of catecholamines from the adrenal medulla is an example of which
type of regulation?
a. Negative feedback
b. Neural
c. Positive feedback
d. Physiologic - ANSWER>>Neural. The release of hormones occurs either in response to an
alteration in the cellular environment or in the process of maintaining a regulated level of
certain hormones or certain substances. Several different mechanisms, one of which is neural
control (e.g., stress-induced release of catecholamines from the adrenal medulla), regulate
the release of hormones.
1. Which hormone does the second messenger calcium (Ca++) bind to activate phospholipase C
through a G protein?
a. Angiotensin II
b. Estrogen
c. Thyroxine
, d. Testosterone - ANSWER>>Angiotensin II. Ca++ is considered an important second messenger
that facilitates the binding of a hormone (e.g., norepinephrine, angiotensin II) to a surface
receptor, activating the enzyme phospholipase C through a G protein inside the plasma
membrane.
1. The control of calcium in cells is important because it:
a. Is controlled by the calcium negative-feedback loop.
b. Is continuously synthesized.
c. Acts as a second messenger.
d. Carries lipid-soluble hormones in the bloodstream. - ANSWER>>Acts as a second messenger.
In addition to being an important ion that participates in a multitude of cellular actions, Ca++
is considered an important second messenger.
1. Where is antidiuretic hormone (ADH) synthesized, and where does it act?
a. Hypothalamus; renal tubular cells
b. Anterior pituitary; posterior pituitary
c. Renal tubules; renal collecting ducts
d. Posterior pituitary; loop of Henle - ANSWER>>Hypothalamus; renal tubular cells. Once
synthesized in the hypothalamus, ADH acts on the vasopressin 2 (V2) receptors of the renal
duct cells to increase their permeability.
1. How does a faulty negative-feedback mechanism result in a hormonal imbalance?
a. Hormones are not synthesized in response to cellular and tissue activities.
b. Decreased hormonal secretion is a response to rising hormone levels.
c. Too little hormone production is initiated.
d. Excessive hormone production results from a failure to turn off the system. -
ANSWER>>Excessive hormone production results from a failure to turn off the system.
