The Adrenal Gland

Question 1

Classify the steroid hormones according to their main physiological effects and the endocrine gland cell types that secrete them.

Answer 1

a

Question 2

Outline schematically the main pathways and cellular compartments involved in the synthesis of steroid hormones; and indicate the main agents and points of control.

Answer 2

a

Question 3

Outline diagrammatically the structure of the (compound) adrenal gland, indicating its zonation, vascularisation and innervation.

Answer 3

a

Question 4

Justify the view that the adrenal cortex is essential for survival of the individual while the adrenal medulla is not.

Answer 4

a

Question 5

Describe the normal circadian basal rhythm in plasma total cortisol concentration.

Answer 5

a

Question 6

Define the term ‘plasma protein bound cortisol’.

Answer 6

a

Question 7

Define the term ‘plasma free cortisol’.

Answer 7

a

Question 8

State the likely effect upon the plasma glucose concentration of administering cortisol to a normal subject; and list the target sites and processes underlying that effect.

Answer 8

a

Question 9

Discuss the clinical features and biochemical diagnosis of the hyperfunction syndromes of the adrenal cortex and medulla (Cushing’s syndrome, Conn’s syndrome and phaeocromocytoma).

Answer 9

a

Question 10

Describe the clinical features, diagnosis and management of adrenal hypofunction (Addison’s disease).

Answer 10

a

Question 11

Discuss the importance of glucocorticoids in acute stress (guidelines for the management of patients on replacement steroids).

Answer 11

a

Question 12

Outline inborn errors of the adrenal glands (congenital adrenal hyperplasia).

Answer 12

a

Question 13

Describe the anatomy of the adrenal gland.

Answer 13

• Situated on the superior pole of the kidney
• Retroperitoneal space
• Each weighs ~4g in adults

Question 14

Describe the adrenal gland structure and function.

Answer 14

Similar to the pituitary, the adrenal gland is composed of two quite separate endocrine glands rolled into one structure.

Adrenal Medulla;

• ~25%
• Modified sympathetic ganglion derived from neural crest tissue
• Secretes catecholamines, mainly epinephrine (adrenaline), also norepinephrine and dopamine

Adrenal Cortex; ~75%
- True endocrine gland
- Derived from mesoderm
- Secretes 3 classes of steroid hormones, the first 2 of which are of particular importance;
+ Mineralocorticoids e.g. aldosterone: involved in the regulation of Na+ and K+
+ Glucocorticoids e.g. cortisol: involved in maintaining plasma glucose
+ Sex steroids e.g. testosterone

Both parts play a role in the body’s response to stress.
Aldosterone and cortisol are essential for survival.