The Endocrine System and Reproductive System
1. Which of the following hormonesenters its target cells before exerting its biological effect?
- DHEA is a steroid hormone, steroid hormones act on receptors located in the cytoplasm and
the nucleus, therefor the hormone must enter the target cell upon exerting its biological
- Other steroid hormones include aldosterone and cortisol
2. A person with an under-functioning pituitary gland will experience functional decline of many
systems.All of the following are likely to occur EXCEPT:
(A) dwarfism if it occurs in childhood.
- Possible cause of GH deficiency directly related to pituitary function
(B) impaired testosteronesecretion in a male.
- Possible cause of LH deficiency directly related to pituitary function
(C) deficiency of aldosterone.
- Aldosterone is produced through the RAAS pathway, angiotensinogen is constantly
produced, and converted to ANG I by renin and ANG II by ACE, ANG II acts on the adrenal
cortex stimulatingthe secretion of aldosterone
- Therefor the pituitary gland is not necessary for the secretion of aldosterone and wont be
effected by under-functioning
(D) cessation of menstrual cycles in a female.
- The menstrual cycle is regulated by changes in hormones such as LH, FSH, estrogen and
progesterone,effecting the secretions of these hormones could effect the menstrual
3. Hormonesfrom the pituitary gland:
(A) travel via axons to the hypothalamus.
(B) inhibit the release of oxytocin and vasopressin.
(C) are carried throughout the body via the hypothalamo-hypophysealportal blood vessels.
(D) can act to inhibit the release of hormones from the hypothalamus.
- Hormones released by the anterior pituitary (ATCH)can act on the hypothalamus to inhibit
the release of the hormone
4. Thyroid hormoneincreases metabolismby stimulating:
(A) lipid synthesis.
(B) the Na+/K+ ATPase.
- Lipid syntheses is a result of increased metabolism, thyroid hormone does not stimulate
action potentials or cell division,therefor Na+/K+ ATPase increases metabolism as a result of
(C) action potentials.
(D) cell division.
5. A person consuming a diet deficient in iodine is likely to have all of the following EXCEPT: (A) an enlarged thyroid gland.
(B) a low plasma concentrationof thyroxine.
(C) a high plasma concentration of thyroid stimulating hormone (TSH).
(D) a low level of thyrotropin releasing hormone(TRH).
- When there are low levels of iodine there are low levels of thyroid hormone (T3,T4 and
calcitonin),this stimulatesthe hypothalamus to produce large amounts of TRH and therefor
stimulates the anterior pituitary to produce large amounts of TSH. TSH activates the thyroid
gland to attempt to make more thyroid hormon