Adrenal Glands Flashcards
what is produced in the zona glomerulosa
mineralcorticoids e.g. aldosterone
what is produced in the zona fasicolata
glucocorticords e.g. cortisol
what is produced in the zona reticularis
androgens
what is produced in the medulla
adrenaline and noradrenaline
what are steroid hormones synthesised from
cholesterol
how do steroid hormones cause their effect
once entering the cell they bind to receptors causing dissociation of the chaperone proteins. the complex then binds to transcription factors or glucocorticoid response elements to alter transcriptions
what is the protein carriers for aldosterone and cortisol
aldosterone = albumin cortisol = transcortin
what does aldosterone do
increases expression of Na/K pump
what is primary hyperaldosterone
a defect in the adrenal cortex causing an increase in aldosterone. this includes hyperplasia and aldosterone secreting adenomas (Conn’s syndrome)
what is secondary hyperaldosterone
where there is a defect in RAAS causing an increase in aldosterone e.g. from renal artery stenosis
what drug should be given in hyperaldosterone
spironolactone - a minercorticoid antagonist
what are catecholamines synthesised from
tyrosine
what is phoachromocytoma
a chromaffin cell tumour where they secrete catecholamines
what are the effects of phoachromocytoma
life threatening hypertension, headahces, weight loss, increased blood glucose
what is congenital adrenal hyperplasia
a autosomal recessive disease where the enzyme 2,1-hydroxylase is missing and so glucocorticoids and mineralcorticoids cant be produced and so their is increased production of androgens
what does cortisol do
increases protein breakdown, gluconeogenesis, lipolysis, anti-inflammatory and suppresses immune system
give 2 examples of synthetic cortisols
prednisolone and hydrocortisone
what diseases can prednisolone be given in
inflammatory (asthma and rheumatoid arthritis), organ rejection
what is cushing’s syndrome
an increase in cortisol
what causes cushing sundrome
- cushing’s disease = pituitary ACTH secreting tumour
- cortisol secreting adrenal tumour
- non pituitary-adrenal ACTH secreting tumour
why does a cortisol secreting adrenal tumour not increase ACTH levels
as cortisol controls the production of ACTH through negative feedback
what are the signs and symptoms of cushing’s syndrome
- increase weight to the abdomen (fat distribution changes)
- thinner arms and legs as proteins break down
- purple stretch marks
- hyperglycaemia
- slightly lower Na and slightly higher K
what is Addison’s disease
a cortisol deficiency
what are the signs of Addison’s disease
weight loss, tiredness, hyperpigmentation, hypoglycaemia
why does hypopigmentation occur in Addinson’s disease
as the POMC which produces the ACTH also produces MSH which activates melanocytes
what are the causes of Addinson’s disease
auto-immune, TB, genetic,
what is the treatment for Addison’s crisis
fluid replacement and cortisol through IV
