Endocrinology- adrenal gland Flashcards
Which main artery and vein are close to Adrenal Gland?
Inferior vena cava
Abdonminal aorta
Which artery and vien supplies each adrenal gland?
left- supplied by abdonminal artery
drains into IVC
right- supplied by abdonminal artery
drains into RENAL VIEN
Both have many arteries only one vien into the gland
Label this histology of adrenal gland (each layer)
What hormones does each layer of adrenal gland produce?
Cortiocsterioids (cortisol)- adrenal cortex (zona golmerulosa, fasciculata, reticularis)
catecholamines (adrenaline)- medulla
Give examples of each catecholamine AND coricoesteriods
catecholamines - noradrenaline and adrenaline
corticosteriod - mineralocoricoids (aldosterone), glucocorticoids (corticol),
_sex steriods only in kids (_androgens and oestrogens)
What does each layer of cortex produce?
zona glomerulosa- aldosterone
(increase Na + reabsorption in blood and k+ excretion in urine and increase blood pressure as increased water retention)
zona fasiculata and reticularis- cortisol + sex hormones
What molecule do all corticosteriods come from?
cholesterol
steriod ( based on cholesterol)
How is progesterone (precursor) synthesized from cholesterol?
Progesterone to aldosterone?
Progesterone to cortisol?
FORGET aldesterone pathway on this
and enzyme is (numbers) HYDROXYLASE
Where do sex steriod come of on the pathway?
How does aldesterone increase blood pressure? (mechanism of action)
activate ATPase and Na+ channel from urine to cell.
so Na+ reabsoprted in tubules in kidney into blood so increase water retention
also K+ and H+ from cell to urine increased
How is it aldosterone regulated?
3 ways
-juxtagolermular appartus measues renal perfusion pressure (blood flow that passes through renal tissue)
- Increase renal sympathetic activity
- decrease Na+ load to top of loop of Henle
ALL release renin into blood
What does renin do?
Switch on cascade to convert to AT to AT 1
eventually to Angiotensin ii that regulates release of aldosterone
How exactly does AT 11 regulate aldosterone release?
Affects all enzyme in pathway to produce aldesterone from cholsterol:
side chain cleavage
3 hydoxysteriod deydro
21, 11, 18 hydroxylase IN golumerulosa
How is cortisol regulated?
By ACTH released by pit gland
What are effects of cortisol
(some similar to glucagon)
stress response, increase blood glucose, lysis of protiens and fat, glucogenosis, enhances effect of glucagon and catechloamines,
excretion of water load and increase vessel permeablity
How is there a negative feedback?
cortisol feedback negatively to pit gland and hypo
How does ACTH stimulate cortisol?
Goes to fasiculata and reticulartis
activates enzymes in pathway from cholesterol to cortisol:
side chain cleavage, 3 hydroxysteriod dehydro
21,11,17 dehydrolase
What is special about fluctations in cortisol levels in body?
diurnal rthym- tells tissues what time of day it is, important waking up
low at midnight
high at 8.30am
tells body what time of day it is
(ACTH slightly ahead)
What is Addison’s disease?
Primary adrenal failure (not enough hormones).
autoimmune disease, destroys cortex.
OR
Tuberclosis-disease
What levels in body give indication?
A lot of ACTH and MSH excreted
low BP
low cortisol and aldesterone
Symptoms of addisons disease?
increase pigmentation, tanned looking
weakness
weight loss
low BP
diarheea
vomitting
Vitiligo (patches of white) might be autommune co-existing as well
Why do addisons have good tan?
POMC is precurosr to produce ACTH, MSH and endorphonines
so when produce a lot of ACTH simulatnously produce a lot of MSH
How can addisons lead to death?
Cortisol and Aldosterone deficiency
Salt loss (Na+)
low BP
death
Treatement of addisons disease?
rehydrate with normal saline (as low blood volume)
Dextrose (glucose) prevent hypoglycaemia due to low glucocorticoid defi
as well as give hydrocortisone (corisol as a medication)
What is name of condition of too much cortisol?
Crushing’s disease
What chemical level changes causes crushing disease?
tumour in adrenal too much cortisol
tumour in pit gland too much ACTH
Symptoms of Crushing disease
increase weight gain
depression
red cheeks
moon face
thin skin
myopathy
thin arms and legs
red striae- stretch marks
poor wound healing
What other condition is commonly associated with Cushing’s syndrome? Why?
Diabities due to insuline resistance
as body becomes resistant to hormones
Possible causes of crushing syndrome?
steriod by mouth- long term do function of cortisol
pituitary adenoma
ectopic (too much) ACTH produced by lung cancer
adrenal adenoma
Clincal signs of crushing disease
thin skin
proximal myopathy- weakness of muscles
centripetal obesity- lemon on stick
hypertension
diabites
immunsupression
moon face
striae- stretch marks
What cells of adrenal medulla derived from?
Ectodermal neural crest
temporary group of cells unique to vertebrates that arise from the embryonic ectoderm germ layer,
What is precusor for catecholamines (noradrenanline and adrenal )?
Tyrosine - amino acid
What trigger release of catecholamines?
Stored in cytoplasmic granules + released in response to ACTH from preganglionic symp neurones
How are they synthesized from tyrosine? (pathway)
(dont need to know enzymes)
What effects do catecholamines have on body?
Fight or flight response
tachycardia, sweating, increase blood glucose, alertness, vasocontriction
How do they travel in blood? Do they travel freely or bound to molecule? And which one?
NA and Adr circulate bound to albumin
How are the NorA and Adr degraded?
monoamine oxidsase and catechol-O-methyl transferase
