3 - Hypothalamus, Pituitary and Adrenal Glands Flashcards
Where is the pituitary gland located?
- Resides in saddle-shaped depression of the sphenoid bone (the depression is called the sella turcica)
- It is a protrusion off the bottom of the hypothalamus at the base of the brain.
What are the neighbors of the pituitary gland?
- Superior: hypothalamus and diaphragma sellae
- Inferior: sella turica, and slightly anterior, sphenoid sinus and optic chiasm
- Lateral: cavernous sinuses
What is the clinical relevance of the location of the pituitary?
It lies in a watershed area of the internal carotids putting it at risk for infarction
What is the surgical approach to the pituitary gland?
Tumor removal is usually accomplished through a transsphenoidal approach
You go in through the nose
What is empty sella syndrome?
Empty sella syndrome is where the pituitary gland shrinks or becomes flattened, allowing cerebrospinal fluid to accumulate
How common is empty sella syndrome symptomatic?
Rarely
What are the two divisions of the pituitary?
- Neurohypophysis
- Adenohypophysis
The two parts are anatomically and functionally distinct
What are the two parts of the neurohypophysis?
Pars nervosa and infundibulum
The infundibulum has two parts as well:
- Medium eminence
- Infundibular process
What are the three parts of the adenohypophysis?
- Pars distalis
- Pars tuberalis
- Pars intermedia
What arteries supply the pituitary gland?
Hypophysial arteries
What are the different hypophysial arteries?
- Superior hypophysial
- Inferior hypophysial
Hypophysial arteries are connected by a trabecular arteries
Which arteries collect the oxytocin and vasopressin from the pituitary gland?
Inferior hypophysial arteries
What arteries receive releasing and inhibitory hormones from hypothalamus
Primary capillary plexus formed by superior hypophysial arteries
What are the type of cells in the pituitary that synthesize both growth hormone (GH) and prolactin?
KNOW THIS
Rare acidophilic stem cells are present in the normal pituitary that are capable of synthesizing and secreting both GH and prolactin
What is the most common cell type in the pituitary?
Somatotropes are acidophils that secrete GH – most frequent cell type
What types of cells in the pituitary that secrete prolactin?
Mammotropes (lactotropes) are acidophils that secrete prolactin
Which type of cells of the pituitary that can secrete both prolactin and GH again?
Rare acidophilic stem cells ***
What happens if there is a tumor of prolactin acidophils in the pituitary?
If there is a tumor in the prolactin acidophils, you can have expression of milk in a non-pregnant woman
What are gonadotropes of the pituitary gland?
Gonadotropes are basophils that secrete LH and FSH. Many gonadotropes synthesize both LH and FSH whereas some gonadotropes synthesize one or the other hormone
Come from the anterior pituitary
What are thyrotropes of the pituitary?
Thyrotropes are basophils that secrete TSH
- First thyrotropin-releasing hormone (TRH) is released which allows for the synthesis and release of TSH (thyroid stimulating hormone) form basophils