The Adrenal Gland

Question 1

Where are the adrenal glands located and how much do they weigh?

Answer 1

On each pole of the kidney and 4g

Question 2

Where does the left adrenal vein drain into?

Answer 2

The right renal vein

Question 3

Where does the right adrenal vein drain into?

Answer 3

Directly into the IVC

Question 4

What are the 2 sections of the adrenal gland and what are their contributing proportions?

Answer 4

The adrenal medulla makes up 25% and the adrenal cortex - 75%

Question 5

From where is the adrenal medulla derived?

Answer 5

The neural crest tissue

Question 6

What is the function of the medulla?

Answer 6

Secretion of catecholamines - epinephrine, norepinephrine and dopamine

Question 7

What 3 classes of steroid hormones does the cortex secrete? Give and example of each

Answer 7

Mineralocorticoids - aldosterone
Glucocorticoids - cortisol
Sex steroids - testosterone

Question 8

Which zone produces mineralocorticoids?

Answer 8

Zona glomerulosa

Question 9

What does bona fasciculata secrete?

Answer 9

Glucocorticoids?

Question 10

What zone secretes the sex hormones?

Answer 10

Zona reticularis

Question 11

What are all steroid hormones derived from?

Answer 11

Cholesterol

Question 12

What is DHEA?

Answer 12

A pre-hormone of testosterone and oestrogen

Question 13

What enzyme is vital in the production pathway of cortisol and aldosterone?

Answer 13

21-hydroxylase

Question 14

A defect in the enzyme 21-hydroxylase will lead to?

Answer 14

Congenital adrenal hyperplasia resulting in the deficiency of aldosterone and cortisol - associated glucose and sodium imbalance

Question 15

What pathway causes adrenal hyperplasia in 21-hydroxylase deficiency?

Answer 15

Lack of the enzyme inhibits the synthesis of cortisol, this results in the loss of the negative feedback on the ACTH and CRH, leading to increased secretion of ACTH and enlargement of the glands

Question 16

What is cortisol

Answer 16

A glucocorticoid hormone that influences glucose metabolism

Question 17

What percentage is bound to its carrier protein?

Answer 17

95%

Question 18

What is the carrier protein for cortisol?

Answer 18

Albumin

Question 19

Why do all cells with the exception of RBC’s respond to glucocorticoids?

Answer 19

Because all nucleated cells have a cytoplasmic glucocorticoid receptor

Question 20

How does the binding of the glucocorticoid bring about an effect within the cell?

Answer 20

The receptor complex migrates to the uncles and causes transcription or translation of certain genes

Question 21

What is the release of cortisol driven by?

Answer 21

The release of ATCH

Question 22

Which half life is longer cortisol or ACTH?

Answer 22

Cortisol - so it persists in the plasma longer

Question 23

When is the biggest release of cortisol? And why?

Answer 23

Between 6 and 8am because this is jus before we get up - very physiologically stressful - have to oppose the forces of gravity and get the CVD demand etc

Question 24

What other stimuli causes the release of cortisol?

Answer 24

Any stressful stimulation

Question 25

Is cortisol critical for life?

Answer 25

Yes

Question 26

What are the consequences of the lack of cortisol?

Answer 26

Body cannot deal with stress - cannot maintain blood glucose levels - protects the brain from hypoglycaemia in normality so this would fail

Question 27

What other substance does it have a permissive effect on?

Answer 27

Glucagon

Question 28

What are the glucocorticoid actions of cortisol(4)?

Answer 28

Gluconeogenesis enhancement
Proteolysis- stimulates the breakdown of protein
Lipolysis - increases free FA’s for food supply
Decreases insulin sensitivity of muscle and adipose tissues

Question 29

Give the 4 non-glucocorticoid actions of cortisol

Answer 29

Negative effect on calcium balance - decreased absorption and increased secretion
Impairs mood and cognition
Permissive effects soon norepinephrine = vasoconstriction
Suppression of the immune system - reduces circulating lymphocyte count

Question 30

What is aldosterone?

Answer 30

Mineralocorticoid which cats on the distal tubules of the kidneys to determine the level so reabsorption of ineratls

Question 31

What are its two main functions?

Answer 31

Increase the reabsorption of sodium and increase the exertion of potassium

Question 32

Where are the effects of aldosterone mainly seen and what are these effects?

Answer 32

The cardiovascular system - increases blood volume and therefore pressure and can also decrease Bp if levels are reduced.