Posterior Pituitary Gland

Question 1

Posterior pituitary gland aka ______ & is composed of ___________.

Answer 1

• Neurohypophysis
• neural tissue

Question 2

2 parts of the posterior pituitary gland

Answer 2

1. Pars nervosa - larger bulbar portion
2. Infundibulum

Question 3

The cell bodies of the neurosecretory cells are in
the _______ and ______ nuclei of the
hypothalamus.

Answer 3

paraventricular & supraoptic nuclei

Question 4

Hypothalamohypophyseal Tract

Answer 4

Originates in the supraoptic nuclei and the paraventricular nuclei of the hypothalamus. These are neurosecretory nuclei, each of which produces oxytocin and vasopressin. Axons of these neurons travel through the infundibulum to terminate in the posterior pituitary.

Question 5

Paraventricular nuclei produces ______.

Answer 5

Oxytocin (OT)

Question 6

Supraoptic nulcei produces ________.

Answer 6

Antidiuretic Hormone (AHD) aka Vasopressin

Question 7

Blood supply of the posterior pituitary gland

Answer 7

Internal carotid arteries → inferior hypophyseal arteries (posterior pituitary) → drain into the capillary plexus of the infundibular process → hormones pass into the posterior hypophyseal veins → distributed to target cells in other tissues.

Question 8

Function of Oxytocin (OT) (during & after delivery of a baby) - affects 2 target tissues:

Answer 8

1. Mother’s uterus
   - During delivery = stretching of the cervix of the uterus → stimulates release of OT → enhances smooth muscle contraction.
2. Breasts
   - After delivery = suckling infant (mechanical stimulus) → stimulates milk ejection (letdown) from the mammary glands.

Question 9

Unsure functions of Oxytocin (OT)

Answer 9

• Foster parental caretaking behavior
• Feeling of sexual pleasure during & after intercourse

Question 10

Function of Antidiuretic Hormone (ADH)

Answer 10

• Acts to retain body H2O & increase blood pressure
• A substance that decreases urine production & causes the kidneys to return more H2O to the blood.

Question 11

What happens when there is absence of ADH?

Answer 11

Urine output will increase more than tenfold, from the normal 1 - 2L to about 20L a day.

Question 12

Alcohol _____ secretion of ADH

Answer 12

inhibits

Question 13

Amount of ADH secreted varies with ______ & ______.

Answer 13

blood osmotic pressure & blood volume

Question 14

Regulation of ADH secretion