Week 3-L3-adrenal gland Flashcards
where are the adrenal gland found
above the kidney
adrenal gland blood supply
many arterial supply but only single venous drainage
right adrenal vein drains into the IVC but left adrenal vein drains into renal vein
draw gross anatomy of the adrenal gland
top->liver and spleen
middle adrenal glands and arterial supply
bottom kidney arterial and venous supply
across IVC and aorta
micro anatomy of adrenal glands
adrenal cortex and adrenal medulla
adrenal cortex made up of
Zona glomerulosa, fasciculate and reticularis
adrenal cortex secretion
corticosteriods e.g.cortisol
adrenal medulla
catecholamines e.g. adrenaline
corticosteroids
mineralocorticoids-aldosterone, glucocorticoids-cortisol, sex steroids-androgen and oestrogen
catecholamines
adrenaline and noradrenaline and dopamine
aldosterone secretion
zona glomerulosa
cortisol androgen and oestrogen secretion
zona fasciculata and reticularis
adrenal cortex micro anatomy
capsule, zona glomerulosa, fasciculata. reticularis and medulla where hormones are transported to the central vein to the blood stream
what is a steroid
derived from cholesterol
adrenal gland secretions precursor
cholesterol
is adrenaline a steroid
no because it is not a cholesterol derived product
number of carbon atoms in a cholesterol molecule
27
enzyme definition
protein that catalyses a specific reaction
enzyme involved with cholesterol->progesterone and which type of reaction
side chain cleavage to pregnenolone and 3-betahydroxy steroid dehydrogenase
oxidation reaction
progesterone to mineralocorticoids
21->11 ->18 hydroxylase
progesterone to glucocorticoids
17->21->11 hydroxylase
aldosterone mechanism of action
stimulate Na+ reabsorption in the DCT, salt reabsorption
stimulates K+ and hydrogen secretion in DCT
increase in Na+ causes reabsorption of water and increase blood pressure while increasing the blood pH more alkaline
aldosterone regulation
juxtaglomerular apparatur JGA- detects drop in BP aka decreased renal perfusion pressure and increase renal sympathetic activity. renin increase secretion in response to drop in blood pressure
aldosterone function
controls blood pressure, control sodium levels and lowers potassium
how is cortisol level regulated
by pituitary gland
effects of cortisol
normal stress response hormone
metabolic effects-peripheral protein catabolism, hepatic glucogenesis, incr blood glucose concentration, fat metabolism andhance effects of glucagon and catecholamines
weak mineralocorticoids effects
renal and cardiovascular effects-excretion of water load and incr vascular permeability
when is cortisol level highest? lowest and how does it vary?
8am or early morning and lowest midnight and decrease during the day
what kind of rhythm does cortisol follow
circadian rhythm
Addison’s disease
primary adrenal failure - do not produce enough steroid hormone
autoimmune disease where the immune system destroy the adrenal cortex
tuberculosis of adrenal gland most common cause
pituitary gland incr ACTH and hence MSH
Addison disease symptoms
low blood pressure weakness weight loss vertigo skin and good tan, hyperpigmentation, gastrointestinal nausea
Addison disease tan cause
pro-opio-melanocortin (POMC) large precursor protein which forms ACTH and MSH. Addison disease cause incr in ACTH and therefore MSH which cause tanning
Addison disease tan cause
pro-opio-melanocortin (POMC) large precursor protein which forms ACTH and MSH. Addison disease cause incr in ACTH and therefore MSH which cause tanning by melanocyte production
Addison disease low blood pressure cause
absence of cortisol or aldosterone
effects of Addison disease
cortisol deficiency, aldosterone deficiency, salt loss, low blood pressure, eventual death
treatment of Addisonian crisis
rehydrate normal saline level
give dextrose for hypoglycaemia-glucocorticoid deficiency
hydrocortisone or another corticoid
Cushing syndrome principle
excessive cortisol or glucocorticoid
Cushing syndrome causes
steroid oral intake,
pituitary dependent oedema
ectopic ACTH- lung cancer
adrenal adenoma/carcinoma
too much cortisol cause
excess cortisol-tumour of adrenal
excess ACTH-tumour of pituitary
Cushing syndrome clinical signs
purple striation, moon face, thin skin, proximal myopathy centripetal obesity, diabetes, hypertension and and osteoporosis, immunosuppression
medulla derived frm
ectodermal neural crest
adrenaline and NA synthesis precursors
tyrosine
catecholamines storage and release
cytoplasmic granules and released with Ash response
sympathetic neurones
roles of catecholamines
fight or flight response
incr cardio rate, sweating, inr blood glucose, alertness and vasoconstriction
NA and adrenaline bound to
albumin
NA and adrenaline degraded by
hepatic enzymes monoamine oxidase and catechol-O-methyl transferase
