Lecture 24 - Adrenal Glands Flashcards
Where do the adrenal glands sit?
on top of the kidneys
What do the adrenal glands consist of?
an outer layer called the cortex and an inner layer called the medulla
What is each adrenal gland essentially?
two glands in one because the cortex and the medulla and functionally and structurally different
What are the 3 layers of the adrenal gland?
outer = zona glomerulosa
middle = zona fasciculata
inner = zona reticularis
What do the cells in the 3 layers contain?
different compliments of enzymes involved in the synthesis of adrenal hormones
What are adrenocorticoids?
refers to their site of origin (adrenal cortex) and steroid nature
mineralocorticoids and glucocorticoids
Mineralocorticoids?
primarily aldosterone
secreted by cells in the zona glomerulosa
What do mineralocorticoids do?
promote Na+ resorption and K+ excretion in kidneys
Glucocorticoids?
primarily cortisol
secreted by cells in the zona fasciculata
What do glucocorticoids do?
regulate the body’s response to stress
regulate glucose levels and have anti inflammatory effects as well
What do mineralocorticoids affect?
water and electrolyte balance
When is there overlap of activity of hormones?
when their structures are similar
Why are synthetic steroids constructed?
to enhance the mineralocorticoid and glucocorticoid activity of the drug
Sex hormones?
primarily androgens
zona reticularis and fasciculata
What do sex hormones regulate?
reproductive function
What do adrenal androgens stimulate in females?
the sex drive
Where else are sex hormones produced?
gonads
What does the adrenal medulla contain?
chromaffin cells which secrete catecholamines
Adrenal medulla hormones?
80% adrenaline
20% noradrenaline
> 1% dopamine
What is the primary stimulus for adrenal medulla hormones?
neural stimulus
What is cortisone?
a metabolite or synthetic form of cortisol
What is cortisol secretion controlled by?
the hypothalamic-pituitary-adrenal axis
What does the hypothalamus secrete?
Corticotrophin releasing hormone (CRH)
What does CRH do?
Acts on the anterior pituitary