The Pituitary Gland and the Hypothalamus

Question 1

Answer 1

Question 2

What is the name given to the depression in the skull where the pituitary gland sits?

Answer 2

Sella turcica

Question 3

In the body of which cranial bone is this?

Answer 3

Sphenoid bone

Question 4

Answer 4

1 = Hypothalamus

2 = Pituitary gland

3 = Optic chiasm

4 = Thalamus and 3^rd ventricle

5 = Sphenoid sinus

Question 5

How is the optic chiasm related to the pituitary gland?

Answer 5

Optic chaism is located anterior to the pituitary stalk

Question 6

Which fibres from the optic nerve, nasal or temporal, cross over to the opposite side at the chiasm?

Answer 6

Temporal

Question 7

What therefore would the resultant visual field defect be due to pituitary gland enlargement?

Answer 7

Bitemporal hemiopia

Question 8

The pituitary gland which is connected to the hypothalamus by the pituitary stalk consists of?

Answer 8

An anterior lobe (pars anterior/adenohypophysis) and a posterior lobe (pars nervosa/neurohypophysis).

Question 9

Answer 9

Question 10

Which is the larger of the two lobes?

Answer 10

Anterior lobe

Question 11

Which of the two lobes is glandular and manufactures numerous hormones?

Answer 11

Anterior lobe

Question 12

What is the function of the posterior lobe

Answer 12

Stores hypothalamic hormones for later release into circulation. Diurectic hormone and oxytocin

Question 13

How does the anterior and posterior pituitary lobes stain?

Answer 13

Anterior pituitary is dark staining while the posterior pituitary is pale

Question 14

Label the pituitary lobes

Answer 14

Question 15

Identify three types of cells

Answer 15

Acidophilic- make all hormones of anterior pituitary except ones that stimulate a few things (which stain pink)

Basophilic- make ACTH, TSH and others (which stain light purple)

Chromophobic – hate colour so that’s why they are called this. Don’t secrete anything(which do not take up much stain and therefore appear pale

Question 16

What hormone(s) do the posterior cells secrete

Answer 16

Oxytocin and ADH

Question 17

What are the 2 classes of acidophil?

Answer 17

Somatotrophs

Mammotrophs

Question 18

What are the secretory products of the 2 acidophil?

What is their target?

Answer 18

Somatotrophs- Growth hormone

General but a major target is the chondrocytes in epiphyseal growth plates. Promotes growth

Mammotrophs- Prolactin

Mammary gland- Milk producing tissue

Question 19

What are the 3 classes of basophils?

Answer 19

Corticotrophs

Thyrotrophs

Gonadotrophs

Question 20

What are the 3 secretory products of basophils and their target?

Answer 20

Corticotrophs- ACTH, MSH. Trophic- general action- promote growth and secretory activity in other endocrine glands. ACTH- Target is the corticosteroid cells of the adrenal cortex. MSH- Melanocytes

Thyrotrophs. TSH. Targets follicular epithelial cells of the thyroid gland

Gonadotrophs- FSH, LH. FSH- Follicular cells of ovaries, to promote growth of follicles, or the Sertoli cells of the testes to promote spermatogenesis. LH- Developing follicles- promotes ovulation. Or Leydig cells of testes- promotes secretion of adrogens aiding in spermatogenesis

Question 21

The arterial blood supply of the pituitary gland is form what?

Answer 21

The superior hypophyseal artery and inferior hypophyseal artery

The superior hypophysial artery enters into the substance of the hypothalamus before breaking up into capillaries (the hypophysial portal system). These capillaries then supply the anterior pituitary gland.

The inferior hypophysial artery supplies the posterior pituitary gland.

Question 22

How does the hypothalamus communicate with the anterior pituitary?

Answer 22

Through releasing and inhibiting hormones- delivered through blood vessels in infundibulum

Question 23

How does the hypothalamus communicate with the posterior pituitary?

Answer 23

Contains end of nerve cells coming from the hypothalamus

Question 24

What is the venous drainage of the pituitary gland through?

Answer 24

Hypophyseal veins into the cavernous sinus