HillcrestLPNPharmacology

2–28. ENDOCRINE CONTROL
a. Antidiuretic Hormone. The effect of ADH on the permeability of water through the tubules is very rapid, and changes in the ADH concentration in the blood are only 10 to 15 minutes behind the change in the solute concentration.
b. Renin and Aldosterone. When the sodium concentration in the blood falls to a very low point or when the blood pressure falls (for example, in hemorrhage), special cells in the nephron release a hormone called renin which acts upon a plasma protein (angiotensinogen) to form angiotensin–2. Angiotensin–2, in turn, acts upon the cortex of the adrenal gland to produce aldosterone. Aldosterone increases Na+ reabsorption and thus increases water reabsorption. This increases the plasma volume and the blood pressure.



SOLUTIONS TO EXERCISES, LESSON 11
1. The endocrine glands are organs of internal secretion. Since they lack a duct
system, they are often called ductless glands. They are usually well supplied with blood
vessels to facilitate the release of their secretions into the blood. (para 11-1)
2. A hormone is a chemical required in very small amounts for the proper
development or functioning of the body. Unlike a vitamin, a hormone is produced within
the body.
The blood carries each hormone to its target organ, whose level of activity in turn
affects the endocrine organ. Thus, to ensure the secretion of just the right amount of
hormone, there is a feedback mechanism. (paras 11-2, 11-3)
3. Many of the hormones of the pituitary body are called "tropins" because they
cause development or activity of the tissues. (para 11-4b)
4. Antidiuretic hormone, (ADH) and oxytocin are produced by the hypothalamus
and released from the posterior pituitary gland.
ADH is involved with the resorption or salvaging of water within the kidneys.
ADH is produced under thirst conditions.
Oxytocin is involved with contractions of smooth muscle in the uterus and with
milk secretion. (para 11-5)
5. Somatotropin, thyrotropin, and adrenocorticotropic hormone (ACTH) are
produced by the anterior pituitary gland.
Somatotropin stimulates the growth of the body in general.
Thyrotropin stimulates the thyroid gland to produce its hormones.
ACTH stimulates the adrenal cortex to produce its hormones. (para 11-6)
6. The pineal gland is apparently associated with sexual drive and reproduction.
(para 11-8)
7. Thyroxin and calcitonin are secreted by the thyroid gland.
Thyroxin affects the basal metabolic rate.
Calcitonin is involved with calcium metabolism. (para 11-9)
8. The hormone of the parathyroid gland is parathormone, important in maintaining
the calcium levels of the body. (para 11-10)
MD0007 11-11
9. Two important hormones of the pancreatic islets are insulin and glucagon.
These hormones are concerned with the glucose levels in the body.
(paras 11-11, 11-12)
10. Epinephrine and norepinephrine are produced by the adrenal medulla. These
hormones mobilize the energy-producing organs and immobilize the others. This is
important during the stress reaction, "fight or flight." (para 11-14)
11. Mineralocorticoids, glucocorticoids, and some sex hormones are produced by the
adrenal cortex. Mineralocorticoids are concerned with electrolytes of the body.
Glucocorticoids are known for their anti-inflammatory effects. (para 11-15)
12. The testes produce male sex hormones, known as androgens.
The female sex hormones are the estrogens and progesterone. The tissues
affected by female sex hormones include the endometrium of the uterus and the
milk-producing portions of the mammary glands. During pregnancy, the placenta
continues the production of progesterone. (paras 11-17, 11-18)
End of Lesson 11