Adrenal cortex Flashcards
What are the 3 zones of the adrenal cortex?
Zona reticularis
Zona fasiculata
Zona glomerulosa
What type of hormones does zona reticularis release?
Glucocorticoids
What type of hormones does zona fasiculata release?
Glucocorticoids
What type of hormones does zona glomerulosa release?
Mineralcorticoids
What is the only type of mineralocorticoid released in abundance?
Aldosterone
What is the only type of glucocorticoid released in abundance?
Cortisol
Describe the renin-angiotensin pathway
Dehydration, Na+ deficiency causes decrease in blood volume, which decreases BP this stimulates juxtaglomerular cells of kidney release renin/ angiotensinogen released form the liver. Angiotensinogen and renin form angiotensin I, this stimulates ACE in the lungs to release angiotensin II
What is the effects of angiotensin II?
Vasoconstriction of arteries - increasing BP.
Increased aldosterone from adrenal cortex
What is the effect of aldosterone on kidneys?
Increased NA+ and water reabsorption, increased K+ into urine, increasing blood volume and increasing BP
What hormones do the posterior pituitary release?
Oxytocin and ADH
What hormone does angiotensin II stimulate eventually?
ADH
Describe the sequence of events leading to release of cortisol
Circadian rhythm and stress cause CRH to be released from hypothalamus. Causing ACTH to be released from anterior pituitary and so cortisol to be released from adrenal cortex
What are the target organs for cortisol?
Imune system, liver, muscle, adipose
What effect does cortisol have on immune system?
Function suppressed
What effect does cortisol have on the liver?
Stimulates gluconeogenesis
What effect does cortisol have on muscle?
Protein catabolism
What effect does cortisol have on adipose tissue?
Lipolysis
In general what is the effect of cortisol?
Protect against hypoglycaemia
What hormone is cortisol similar to?
Glucagon - but it suppresses the immune system aswell
What is the relationship between cortisol and glucagon?
Cortisol must be present to ensure full responsiveness to glucagon
What is the problem with cortisol supplements?
Will start negative feedback loop and shut down hypothalamus, pituitary adrenal axis so own cortisol is not made - cannot stop taking supplements straight away
What is Cushings syndrome?
Excess cortisol
What causes excess hormone release?
Adrenal tumour
