Chapter 65- Hypothalamic-Pituitary Axis

Question 0

Where does the pituitary gland lie in the skull?
What borders the pituitary gland laterally?
What courses over the superior aspect of the pituitary gland?
2/3 of the pituitary gland is composed of the _______, and 1/3 is the ______.

Answer 0

• it lies in the sella turcica with the sphenoid bone
• cavernous sinus borders laterally
• optic chiasm courses over the pituitary gland
• 2/3 of the pituitary gland is composed of the anterior lobe, and 1/3 is the posterior lobe

Question 1

How does the anterior pituitary gland receive hypothalamic stimulatory and inhibitory hormones?

Answer 1

via a hypothalamic pituitary portal circulation

**The anterior pituitary gland receives a rich vascular supply largely form the hypothalamus

Question 2

What are the 6 anterior pituitary hormones?

Answer 2

1. adrenocorticotropic hormone (ACTH)
2. growth hormone (GH)
3. prolactin (PRL)
4. Thyroid stimulating hormone (TSH)
5. gonadotropins luteinizing hormone (LH)
6. follicle stimulating hormone (FSH)

Question 3

What hormones are secreted from the posterior pituitary?

Answer 3

1. Arginine vasopressin (ANP), also known as antidiuretic hormone (ADH)
   * *synthesized in the hypothalamus and transported through the pituitary stalk to the posterior lobe of the pituitary gland, where it is stored and available to be secreted.
2. Oxytocin - stored and secreted by the posterior pituitary lobe

Question 4

What are the most common secretory pituitary tumors?

Answer 4

Prolactinomas

Question 5

_____ is a frequent symptom of pituitary tumors. If the tumor extends into the suprasellar space, the optic chaism may become compressed, which classically results in ________.

Answer 5

Headache

bitemporal hemianopia

Question 6

Lateral extension into the cavernous sinus can result in _____, _____, ______ as a result of dysfunction of the _____, ______, and _____ cranial nerves.

Answer 6

ophthalmoplegia, diplopia, or ptosis as a result of dysfunction of the 3rd, 4th, and 6th cranial nerves

Question 7

Destructive pituitary lesions result in hormone loss, which follows a particular pattern: ……… what is the pattern?

Answer 7

1. Initially GH is reduced
2. Followed by LH and FSH reduction
3. then TSH
4. lastly ACTH reduction

Question 8

How do you confirm the presence of a pituitary tumor?

How do you differentiate small pituitary lesions from normal anterior pituitary tissue?

Answer 8

1. MRI

2. contrast agent gadolinium is used

Question 9

pituitary lesions that are less than 10 mm in diameter

Answer 9

microadenomas

Question 10

pituitary lesions that are greater than 10 mm in diameter

Answer 10

macroadenomas

Question 11

Macroadenomas and microadenomas may cause deviation of the ________.

Answer 11

pituitary stalk to the opposite side

Question 12

Adenomas exceeding ______ frequently have suprasellar extension with compression and displacement of the optic chiasm.
**what would this cause :) it was on a card earlier!!!

Answer 12

15 mm

** it would cause bitemporal hemianopia

Question 13

A primary congenital defect or herniation of the arachnoid membrane, through an incompetent diaphragma sella, either after pituitary surgery or radiation, can cause ____________.

Answer 13

Empty Sella Syndrome

Question 14

What is the most common cause of an enlarged sella?

Answer 14

Empty Sella Syndrome

• *caused by a congenital defect
• *or caused by herniation of the arachnoid membrane after pituitary surgery or radiation

Question 15

______ should precede IMAGING STUDIES because about 10% to 20% of the normal population harbors nonfunctional asymptomatic pituitary microadenomas. that are incidentally detected by MRI.

Answer 15

Endocrine evaluation