SFP: pituitary histology

Question 1

What are the parts of the pituitary?

Answer 1

The adenohypophysis (anterior pituitary) and neurohypophysis (posterior pituitary)

Question 2

What are the parts of the adenohypophysis?

Answer 2

Pars distalis

Question 3

Describe the basic histology of pars distalis.

Answer 3

Cords of glandular epithelium surrounded by fenestrated capillaries that form the secondary plexus of hypothalamo-hypophyseal portal system

Question 4

What are the types of glandular cells in the pars distalis?

Answer 4

Chromophils and chromophobes. Chromophils stain acidophilic or basophilic while chromophobes will stain the same but very weakly since they are degranulated.

Question 5

What chromophil types are acidophilic?

Answer 5

Somatotrophs and mammotrophs

Question 6

What do somatotrophs make?

Answer 6

Growth hormone

Question 7

Describe mammotrophs.

Answer 7

Basophilic cells in the anterior pituitary that make Prolactin

Question 8

Describe thyrotrophs.

Answer 8

Basophilic cells in the anterior pituitary that make Thyroid stimulating hormone

Question 9

Describe corticotrophs.

Answer 9

Basophilic cells in the anterior pituitary that make ACTH

Question 10

Describe gonadotrophs.

Answer 10

Basophilic cells in the anterior pituitary that make FSH and LH

Question 11

What is clathrin?

Answer 11

Coat protein used by the trans Golgi to facilitate sorting of secretory proteins into vesicles

Question 12

Describe fenestrated capillaries.

Answer 12

Contain tight junctions, continuous basal lamina, and fenestrae in the plasma membrane covered by a thin diaphragm. This allows exchange of things like hormones but not larger things like formed elements.

Question 13

What is the diaphragm in a fenestrated capillary composed of?

Answer 13

Heparin sulfate proteoglycans

Question 14

Describe pars intermedia.

Answer 14

A narrow strip of glandular epithelial cells between pars distalis and pars nervosa

Question 15

What does the pars intermedia produce in the fetus?

Answer 15

Melanocyte stimulating hormone

Question 16

What is produced by pars intermedia?

Answer 16

MSH, b-endorphin, y-lipotropin

Question 17

What cell types are found in pars intermedia?

Answer 17

Basophils and chromophobes

Question 18

What are Rathke’s pouch?

Answer 18

What the anterior pituitary is derived from; remnants of the pouch leave fluid-filled cysts.

Question 19

Describe pars tuberalis.

Answer 19

Glandular epithelial cells surrounding the infundibular stalk

Question 20

What cell types are in the pars tuberalis?

Answer 20

Basophils and chromophobes

Question 21

What hormones are secreted by the pars tuberalis?

Answer 21

FSH and LH

Question 22

Briefly describe the neurohypophysis.

Answer 22

Not a true gland, so doesn’t contain secretory cells, it is neural tissue that contains unmyelinated axons derived from secretory neurons and receives hormones from the hypothalamus.

Question 23

Describe neurons in the neurohypophysis.

Answer 23

The cell body is found in the hypothalamus, and the axons extend into the neurohypophysis.

Question 24

What are herring bodies?

Answer 24

Dilations of axon terminals containing secretory granules produced in the neuronal body. These are found in the neurohypophysis.

Question 25

What are pituicytes?

Answer 25

Specialized glial cells in the neurohypophysis

Question 26

What hormones are associated with the neurohypophysis?

Answer 26

Oxytocin and ADH

Question 27

What is neurophysin?

Answer 27

A carrier protein that binds to/transports hormones to the posterior pituitary from the hypothalamus; they are synthesized together and then cleaved.

Question 28

Oxytocin binds ___

Answer 28

Neurophysin I

Question 29

ADH binds ___

Answer 29

Neurophysin II