Adrenocortical Function and Dysfunction

Question 1

What are the 2 glands that make up the adrenal and what makes them different?

Answer 1

the adrenal medulla is a modified sympathetic ganglion that secretes catecholamines and the adrenal cortex is a true endocrine gland that secretes steroids

Question 2

What are the layers of the adrenal cortex from out to in?

Answer 2

zona glomerulosa, zona fasciculata, zona reticularis

Question 3

Where are the sex hormones made in the adrenal cortex?

Answer 3

in the zona reticularis (and also fasciculata)

Question 4

Where are the glucocorticoids made in the adrenal cortex?

Answer 4

in the zona fasciculata (and also the zona reticularis)

Question 5

Where are the mineralocorticoids made in the adrenal cortex?

Answer 5

in the zona glomerulosa

Question 6

What other effect does ACTH have on the adrenal gland apart from glucocorticoid release?

Answer 6

tropic to zona reticularis and zona fasciculata

Question 7

Why does excessive cortisol cause high blood pressure?

Answer 7

because the chemical structure of cortisol and aldosterone is similar and so cortisol can act on the aldosterone receptor to cause the same effects as aldosterone

Question 8

What does inhibition of the enzyme aromatase cause?

Answer 8

more male sex steroids than female sex steroids

Question 9

What enzyme creates glucocorticoids?

Answer 9

hydroxylase

Question 10

Which protein must be cleaved to create ACTH?

Answer 10

POMC

Question 11

Which POMC fragment is responsible for blocking pain perception?

Answer 11

beta endorphin

Question 12

What is the action of ACTH in non-pituitary tissues?

Answer 12

it is cleaved into alpha-MSH which is responsible for melanin synthesis, immune response and decreasing food intake

Question 13

Which hormones is cortisol permissive for?

Answer 13

glucagon and catecholamines

Question 14

What time of day is plasma cortisol the highest?

Answer 14

usually the morning

Question 15

How does cortisol effect calcium balance?

Answer 15

decreases absorption, increases excretion and increases bone breakdown

Question 16

Is cortisol made on demand or stored?

Answer 16

made on demand

Question 17

What is the half life of cortisol?

Answer 17

60-90 minutes

Question 18

What enhances the release of cortisol?

Answer 18

stress

Question 19

What are the symptoms of hyperaldosteronism?

Answer 19

hypernatremia, hypokalemia, hypertension

Question 20

What are the causes of Cushing’s syndrome?

Answer 20

adrenal tumour, pituitary tumour and iatrogenic hypercortisolism

Question 21

What causes adrenogenital syndrome (excess androgen and oestrogen)?

Answer 21

lack of enzyme in cortisol pathway

Question 22

What are the symptoms of Cushing’s syndrome?

Answer 22

hyperglycaemia, muscle wasting, fat deposition in face, neck and stomach, hypertension, osteoporosis, mood elevation and depression, problems with learning and memory

Question 23

What is Addison’s disease and what are the symptoms?

Answer 23

autoimmune destruction of the adrenal cortex - causes cardiac arrhythmias, hypotension and hypoglycaemia

Question 24

What is the impact of a pituitary or hypothalamic pathology on aldosterone?

Answer 24

no impact - aldosterone will be normal but cortisol will be low

Question 25

Why is adrenaline only produced in the adrenal medulla?

Answer 25

because this is the only site with the enzyme PMNT required for adrenaline synthesis

Question 26

What are the actions of adrenaline?

Answer 26

increase heart rate and contractility, increase TPR, increase BP, increase glucose and free fatty acids to increase basal metabolic rate, increase arousal and alertness

Question 27

What are the symptoms of hypersecretion of the adrenal medulla?

Answer 27

hypertension - deadly