Adrenal Gland Flashcards
(34 cards)
What two anatomical sections can the adrenal gland be divided into? What do the secrete?
Medulla - secretes Adrenaline, Noradrenaline.
Cortex - secretes glucocorticoids and adrenal androgens.
Where are the adrenal glands?
Paired glands, located near the kidneys.
What 3 areas can the Adrenal Cortex be divided into? How large are they (proportionately)?
Zona Glomerulosa - nearest capsule. Smallest part. Zona Fasiculata - largest part in middle, large no of lipid droplets. Zona Reticularis - nearest medulla. Around 30% of cortex.
What is the Zona Glomerulosa? What does it secrete?
ZG is the smallest part of the adrenal cortex. It secretes mineralocorticoids such as Aldosterone.
What is the Zona Fascularis? What does it secrete?
Largest part of the adrenal cortex. It secretes Glucocorticoids, e.g. cortisol.
What is the Zona reticularis? What does it secrete?
ZR is part of the adrenal cortex, it secretes adrenal androgens (DHEA, Androsteinedione)
How can cholesterol be utilised? (3 ways)
Cholesterol esters in vesicles (Finite), Lipoproteins in circulation, or it can be made from Acetate.
How does cholesterol get into a cell? How does it then get into the mitochondria?
Cholesterol gets into cell uses StAR. It then gets into mitochondria by conversion into Pregnenolone by CSCC.
What is the pathway from Cholesterol to Androgens?
Cholesterol - Pregnenolone - 17ahydroxypregnenolone - DHEA - Androsteinedione - Androgens
What is the pathway from Cholesterol to Aldosterone?
Cholesterol - Pregnenolone - Progesterone - Deoxycorticosterone - Corticosterone - Aldosterone
What is the pathway from Cholesterol to Cortisol?
Cholesterol - Pregnenolone - 17ahydroxypregnenolone - 17aHprogesterone - Deoxycortisol - Cortisol
How can excess ACTH affect pigmentation of skin?
ACTH can bind to MSH receptors when it is in excess, which causes hyperpigmentation.
How is Aldosterone synthesis controlled?
RAAS System. Increased AII, Increased K, increase aldosterone. ANP causes a decrease in aldosterone. ACTH does not have a huge effect.
What is the RAAS?
Renin from JGA in Kidneys converts Angiotensinogen to Angiotensin I, converted to Angiotensin II, which increases Aldosterone synthesis.
How is adrenal androgen synthesis controlled?
ACTH is a potent stimulator.
How are Glucocorticoids usually transported in the blood?
Usually transported bound to CBG (Corticosteroid Binding Globulin).
What are the main affects of Glucocorticoids?
Anti-inflammatory, Immunosuppressive, Reduce growth in young subjects, Stress response. Increase plasma glucose.
What are the actions of Mineralocorticoids?
Aldosterone increases Na retention, and increases K excretion.
What is Cushing’s syndrome?
Cushing’s syndrome is an excess of Cortisol. It can be caused by either increased ACTH (pit. dependent - Cushing’s disease) or adrenal tumours (rarer).
What are the clinical signs of Cushing’s syndrome?
Pot bellied, Hyperpigmentation, Alopecia.
What is Hyperaldosteronism? What is Primary/Secondary?
Excess aldosterone. Primary aldosteronism is a result of a problem with the adrenal gland itself, secondary is other factors e.g. More AII.
What are the main consequences of Aldosteronism?
More Na retention, More K excretion. Increase in heart rate, muscle weakness and arrthymias, Hypertension due to increased water and salt in blood.
What is Addison’s disease? What are the main causes?
Addison’s disease is Hypoadrencorticism, where there is a lack of mineralocorticoids and glucocorticoids. May be due to adrenal atrophy.
What are the main effects of Addison’s disease?
Mainly due to lack of Mineralocorticoids. Hyperkalemic, Bradycardia, Dehydration. Underperfusion.
