EXAM #1: PITUITARY ANATOMY & HISTOLOGY

Question 1

What structures lie superior to the pituitary gland?

Answer 1

Diaphragma sellae* and hypothalamus

Dura mater that forms a roof over the pituitary–this is what the infandibulum passes through

Question 2

What structures lie lateral to the pituitary gland?

Answer 2

Cavernous sinuses

Question 3

What is contained within the cavernous sinuses?

Answer 3

Internal carotid arteries and cranial nerves

Question 4

What structure lies anteroinferior to the pituitary gland?

Answer 4

Sphenoid sinus

*Note that this allows the pituitary gland to be accessed surgically via a “transsphenoidal approach” i.e. through the nose

Question 5

What separates the pituitary gland from the sphenoid sinus?

Answer 5

Sella turcica

This is a depression in the sphenoid bone, containing the pituitary gland.

Question 6

What major structures will be compromised by a pituitary tumor?

Answer 6

1) Internal carotid a. which can lead to infarction

2) CN III, V, VI i.e. CN palsy

Question 7

What type of infarct results from stenosis of the internal carotid arteries secondary to a pituitary tumor?

Answer 7

“Watershed” infarct

Question 8

What is empty sella syndrome?

Answer 8

This is a defect in the dura forming the digphragma sella

*Increased space allows for increased pressure to be placed on the pituitary gland from surrounding CSF

Question 9

What are the three portions of the anterior pituitary gland? What is the major division?

Answer 9

1) Pars distalis (major)
2) Pars tuberalis (surrounds infandibulum)
3) Pars intermedia (between the first two)

Question 10

What are the two major divisions of the posterior pituitary gland?

Answer 10

1) Pars nervosa (neurons)

2) Infundibular stalk

Question 11

What is the embryonic origin of the anterior pituitary?

Answer 11

Oral ectoderm that develops into “Rathke’s Pouch” (and then the anterior pituitary)

Question 12

What is the embryonic origin of the posterior pituitary?

Answer 12

Neuroectoderm

Question 13

What are the two major signaling molecules that drive the development of the pituitary gland?

Answer 13

1) Bone morphogenic protein 4

2) Fibroblast growth factor 8

Question 14

What is a pediatric craniopharyngioma?

Answer 14

This is when remnants of Ratheke’s pouch/cleft that do not regress in the formation of the anterior pituitary

Question 15

What is an adult craniopharyngioma?

Answer 15

Anterior pituitary tumor that forms from mature cells

Question 16

What structures form from the superior hypophysial artery? What region of the pituitary does it exert influence over?

Answer 16

1) Primary capillary plexus
2) Portal veins
2) Secondary capillary plexus

*Anterior pituitary

Question 17

What is carried in the primary/secondary capillary plexi?

Answer 17

Releasing and inhibitory hormones from hypothalamus

Question 18

What forms from the inferior hypophysieal artery? What region of the pituitary is it associated with?

Answer 18

Capillary plexus of the posterior pituitary

*Associated with the posterior pituitary

Question 19

What is the normal histological appearance of the pars distalis?

Answer 19

Abundant reticular connective tissue

Question 20

What does “scant reticular connective tissue” indicate?

Answer 20

Pituitary adenoma

Question 21

What are the three types of cells in the pars distalis based on staining characteristics?

Answer 21

Basophil= dark 
Acidophil= lighter 
Chromophobe= lightest

Question 22

What type of technique can be used to identify the functional classification of cells in the pituitary gland?

Answer 22

Immunocytochemistry

Question 23

What hormone is produced by somatotropes?

Answer 23

Growth Hormone

Note that these are acidophils, and the most frequent cell type

Question 24

How does GH induce its action?

Answer 24

Insulin-like growth factor-1 (from hepatocytes)

Question 25

What is the function of GH?

Answer 25

Induce growth of bones at the epiphyseal plates

Question 26

What is secreted by mammotropes?

Answer 26

Prolactin

Question 27

What type of cell is the mammotrope histologically?

Answer 27

Acidophils

Question 28

What is secreted by the gonadotropes?

Answer 28

FSH and LH

Question 29

What type of cell is the gonadotrope histologically?

Answer 29

Basophil

Question 30

What is secreted by the thyrotropes?

Answer 30

TSH

Question 31

What type of cell is the thyrotrope histologically?

Answer 31

Basophil

Question 32

What is secreted by the corticotropes?

Answer 32

ACTH and β-lipotrophic hormone

Question 33

What type of cell is the corticotrope histologically?

Answer 33

Basophil

Question 34

What hormone is increased by the action of ACTH?

Answer 34

Cortisol

Question 35

Histologically, what happens to corticotropes in response to excess glucocorticoids?

Answer 35

“Crooke’s hyaline change”

Question 36

Where are the cell bodies of the neurohypophysis?

Answer 36

Supraoptic and paraventricular nuclei of the hypothalamus

Question 37

What is secreted by the neurohypophysis?

Answer 37

ADH and oxytocin

Question 38

What are the supporting cells in the neurohypophysis?

Answer 38

Pituicytes

Question 39

What is a herring body?

Answer 39

Neurosecretory terminal end of the axons from the hypothalamus in the posterior pituitary

Question 40

What is the MOA of vasopressin?

Answer 40

1) Increased permeability of the collecting tubule to water

2) Vasoconstriction

Question 41

What are the functions of oxytocin?

Answer 41

1) Uterine contraction

2) Milk release