Physiology Flashcards
What hormones does the anterior pituitary gland produce?
FLAT PEG
F - FSH L - LH A - ACTH T - TSH P - Prolactin E - Endorphins G - GH
What hormones does the posterior pituitary gland produce?
- ADH
- Oxytocin
How is cortisol released?
Hypothalamus -> CRH -> anterior pituitary -> adrenal glands -> cortisol
Where is cortisol released from the adrenal glands?
Zona Fasciculata
What else does ACTH stimulate the release of
Small amounts of androgens
What is the function of cortisol?
- Stimulates amino acid release
- Stimulates lipolysis
- Stimulates gluconeogenesis
- Increases blood glucose levels in response to stress, by inhibiting glucose uptake into muscle and fat cells
- Strengthens cardiac muscle contractions
- Increases water retention
- Has anti-inflammatory and anti-allergic effects
Where are androgens converted into testosterone and oestrogen?
Gonads
How is GH released?
Hypothalamus -> GRHR -> anterior pituitary -> GH
What is the function of GH?
Triggers the production of IGF-1 • Stimulates muscle growth • Increases bone density and strength • Stimulates cell regeneration and reproduction • Stimulates growth of internal organs
How are FSH and LH released?
Hypothalamus -> GnRH -> anterior pituitary -> FSH and LH
What is the function of FSH?
- Stimulates maturation of sex cells/gametes
- Promotes follicular growth
What is the function of LH?
- Triggers ovulation in women
- Triggers production of oestrogen and progesterone by ovaries
- Stimulates production of testosterone by testes
What is the function of prolactin?
- During pregnancy = contributes to development of mammary glands
- After pregnancy = Lactation (milk production) in women
What is the function of ADH?
ADH acts on the collecting ducts of the kidneys to increase the number of aquaporin channels, allowing water to be reabsorbed.
How is ADH released?
If plasma osmolarity increases (due to increased sodium) or body water decreases receptors in the hypothalamus cause ‘thirst’ to increase water intake.
The receptors cause a signal to the posterior pituitary gland to cause the release of ADH.
What is PTH released in response to?
Low calcium
Low magnesium
High phosphate
What is the function of the PTH?
Increase serum calcium by:
• Increases the number and activity of osteoclasts in bone
• Increase in calcium reabsorption in the kidneys
• Stimulates kidneys to convert vitamin D3 into calcitriol (active form of vitamin D)
What are the layers outer-inner of the cortex of the adrenal glands?
- Zona Glomerulosa
- Zona Fasciculata
- Zona Reticularis
What is produced in the zona glomerulosa of the adrenal cortex?
Mineralocorticoids (aldosterone)
What is produced in the zona fasciculata of the adrenal cortex?
Glucocorticoids
What is produced in the zona reticularis of the adrenal cortex?
Androgens
What is produced in the adrenal medulla?
- Catecholamines
- Enkephalins
What is congenital adrenal hyperplasia?
• Lack of mineralocorticoids and glucocorticoids and excess testosterone and its derivatives
