Posterior Pituitary Hormones Flashcards
What is the anterior pituitary gland known as?
Adenohyophysis
What’s the posterior pituitary gland known as?
Neurohypophysis
What hormones do the posterior pituitary gland secrete
ADH and Oxytocin
What is antidiuretic hormone also known as?
Arginine vasopressin
What kind of just hormone are ADH and vasopressin?
Peptide hormones that are 9 aa long
What is the segment on ADH that’s cleaved?
Neurophysis 2
What’s the segment on oxytocin that’s cleaved?
Neurophysis 1
What is hypophysectomy?
It’s pituitary removal
What happens after hypophysectomy?
There’s a reduction in posterior protein secretion, but overtime, several ends of the hypothalamic hypophyseal Tract is modified so secretions are returned to normal.
What does adh do?
It increases water retention in the kidneys by increasing permeability of the nephron to water. This decreases urine production. Vasoconstriction of blood vessels also occur.
What happens in the absence of ADH?
The collecting ducts and tubules become almost impermeable to water
What’s the mechanism of action for ADH?
CAMP levels increase when adenylyl cyclase. This increases the number of water channels onto PM. it’s translocated from an intracellular storage site.
What else does ADH do
It’s stimulates arteriolar constriction. It also stimulates renal mesangial cell contraction. It also stimulates acth secretion. It also inhibits renin secretion. It also influences behaviour, learning and memory.
What stimulates ADH secretion?
- When osmotic pressure increases (larger electrolyte concentration)
- Loss of blood – volume receptors located in the atria of the heart detect changes in blood volume and send signals to increase ADH secretion.
What decreases ADH secretion?
Alcohol. Consumption leads to dehydration.
