What are clinical manifestations of hypothyroidism?
a. Intolerance to heat, tachycardia, and weight loss
b. Oligomenorrhea, fatigue, and warm skin
c.
... [Show More] Restlessness, increased appetite, and metrorrhagia
d. Constipation, decreased heat rate, and lethargy
The lower levels of thyroid hormone result in decreased energy metabolism, resulting
in constipation, bradycardia, and lethargy, thus eliminating the remaining options.
2. 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
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.
3. 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
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.
4. 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. 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.
5. Which mineral is needed for thyroid-stimulating hormone (TSH) to stimulate the
secretion of thyroid hormone (TH)?
a. Iron
b. Iodide
c. Zinc
2
d. Copper
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 [Show Less]