Fundamentals of Anatomy and Physiology

The Endocrine System 285

Pineal

Isthmus Pituitary

Isthmus

Thyroid and

parathyroid

Thymus

Adrenal gland

(suprarenal gland)

Pancreas

Testis male

Figure 12- 3 The endocrine glands and their locations in the
body.

Ovary female

(^) ®
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Follicle-stimulating hormone (FSH) stimulates
de-velopment of the follicles in the ovaries of females. In
males, it stimulates the production of sperm cells in the
seminiferous tubules of the testes.
Luteinizing (LOO-tee-in-eye-zing) hormone (LH)
stimulates ovulation in the female ovary and produc-tion of
the female sex hormone progesterone. It helps maintain
pregnancy. In males, it stimulates the synthe-sis of
testosterone in the testes to maintain sperm cell production.
Lactogenic hormone (LTH), also known as -prolactin^
(proh-LACK-tin), stimulates milk production in the
mammary glands following delivery in a pregnant female-.
It also maintains progesterone levels following ovulation
and during pregnancy in women. In males, it appears to
increase sensitivity to LH and may cause a decrease- in
male sex hormones.
The Posterior Pituitary Gland
and Its Hormones
The posterior pituitary lobe consists primarily of nerve
fibers and neuroglial cells that support the nerve fibers,
whereas the anterior lobe is primarily glandular epithelial
cells. Special neurons in the hypothalamus produce the
hormones of the posterior pituitary lobe. These hormones
pass down axons through the pituitary stalk to the posterior
lobe, and secretory granules near the ends of the axons
store the hormones (see F igure 12-2).
Antidiuretic (an-tye-dye-yoo-RET-ik) hormone
(ADH), also known as vasopressin (vaz-oh-PRES-sin),
maintains the body’s water balance by promot-ing
-increased water reabsorption in the tubules of the nephrons
of kidneys, resulting in less water in the urine. If -secreted
in large amounts, ADH can cause constriction