Endocrine Physiology - The Pituitary Gland Flashcards
1
Q
Describe the hypothalamus.
A
- Integration centre for endocrine systems
- Located at the base of the brain, below the thalamus
- Connected to the pituitary via the infundibulum
2
Q
Describe the pituitary gland.
A
- Bean-shaped and bean sized endocrine gland (around 14mm diameter)
- Located in the pocket in the sphenoid bone, directly below the hypothalamus
- Contains 2 distinct types of tissue - anterior and posterior pituitary
3
Q
What type of communication exists between the hypothalamus and pituitary gland?
A
Both neural (to the posterior pituitary) and endocrine (to the anterior pitutiary) hence its neuroendocrine function.
4
Q
What are the two types of hypothalamic neurohormones?
A
- Tropic - govern the release of anterior pituiatry hormones
- Non-tropic - travel to posterior pituitary via axons of hypothalamic neurons
5
Q
Describe the anterior pituitary.
A
- true endocrine organ
- connected to hypothalamus via hypothalamic-hypophyseal portal system
- the production of anterior pituitary hormones is controlled by the hypothalamus
6
Q
What is another name for the posterior pituiary lobe?
A
Neurohypophysis
7
Q
Function of the posterior pituitary.
A
Stores and releases 2 peptide neurohormones:
- vasopressin ( aka anti-diuretic hormone; ADH)
- oxytocin
8
Q
Main function of vasopressin.
A
Regulates water balance.
9
Q
Vasopressin release triggered by:
A
- increased plasma osmolarity
- decreased volume/blood pressure
10
Q
Vasopressin site of action.
A
- kidney collecting ducts → increased water reabsorption
- vascular smooth muscle → increased blood pressure
11
Q
Oxytocin main function
A
-milk ejection and uterine contraction
12
Q
Oxytocin release triggered by:
A
- labour (babys head againts cervix)
- suckling
13
Q
Oxytocin site of action:
A
- milk duct smooth muscle → contacts muscle, ejecting milk
- uterine smooth muscle → child birth
