Adrenal Physiology

Question 1

What are the layers that make up the cortex of the adrenal gland

Answer 1

Outer capsule
Zona glomerulosa
Zona fasciculata
Zona reticularis

Question 2

Overview of corticosteroids

Answer 2

They are lipid soluble
Bind to intracellular receptors
Alter gene transcription directly or indirectly
Action depends on structure

Question 3

What corticosteroid is synthesised in the Zona glomerulosa

Answer 3

Mineralocorticoids such as aldosterone

Question 4

What corticosteroid is synthesised in the Zona fasciculata

Answer 4

Glucorticoids such as cortisol

Question 5

What corticosteroid is synthesised in the Zona reticularis

Answer 5

Androgens such as DHEA and androstenedione

Question 6

What is the function of the hormones synthesised in the Zona glomerulosa

Answer 6

They are important for regulating fluid balance

Question 7

What percentage of the cortex does the Zona glomerulosa account for

Answer 7

15%

Question 8

What type of hormones are mineralocorticords

Answer 8

Steroid hormones

Question 9

What is the function of aldosterone

Answer 9

Responsible for controlling the uptake of Na+ and secretion of K+ in the collecting duct of the Renal tubule

Question 10

What factors increase the rate of aldosterone production in the Zona glomerulosa

Answer 10

Increased plasma concentration of angiotensin-II
Increase in plasma K+ concentration
Decrease in plasma pH
Decrease in blood pressure

Question 11

What causes Conn’s syndrome

Answer 11

It is caused by an Adenoma/benign tumour in the Zona glomerulosa which causes excess secretion of aldosterone

Question 12

Which is the thickest layer of the adrenal cortex

Answer 12

The Zona fasciculata

Question 13

What percentage of the cortex does the Zona fasciculata make up

Answer 13

50%

Question 14

What type of cell is the Zona fasciculata made up of

Answer 14

Parenchymal cells known as spongiocytes

Question 15

What is the function of hormones made in the Zona fasciculata

Answer 15

They regulate carbohydrate metabolism particularly when an individual is in a time of stress

Question 16

What causes Cushing’s syndrome

Answer 16

A patient with Cushing’s syndrome will have symptoms of high gluticocorticoid secretion and show effects of high mineralcorticoid concentrations

Question 17

What can cause Addison’s disease

Answer 17

Lack of cortisol due to an autoimmune destruction of the adrenal cortex

Question 18

What is the function of the androgens secreted from the Zona reticularis

Answer 18

They are largely responsible for the Normal development of sexual characteristics during puberty

Question 19

How are adrenal androgens regulated

Answer 19

Adrenal androgens are regulated by ACTH which is secreted from the anterior pituitary stimulated by the release of CRH into the hypophyseal portal system by the hypothalamus

Question 20

What is the adrenal medulla

Answer 20

It is the central part of the adrenal gland and is surrounded by it the cortex

Question 21

What is the role of the adrenal medulla

Answer 21

Plays a very important role in homeostasis, secreting essential hormones such as adrenaline and noradrenaline

Question 22

What are the main secreting cells of the medulla

Answer 22

Chromaffin cells (modified sympathetic ganglia) derivatives of neural crest cells

Question 23

When is adrenaline released from the medulla

Answer 23

In response to the activation of the sympathetic nervous system

Question 24

What is the main function of the adrenal medulla

Answer 24

Primary function = Synthesising catecholamines such ad adrenaline and noradrenaline

Secondary function = production of dopamine

Question 25

What is a phaeochromocytoma

Answer 25

A neuroendocrine tumour of the adrenal medulla specifically within the chromaffin cells