Hypothalamic Pituitary Adrenal Axis

Question 1

Which hormone is produced from the hypothalamus as part of the hypothalamic pituitary adrenal axis

Answer 1

Corticotropin releasing hormone (CRH)

Question 2

How is corticotropin releasing hormone (CRH) transported to the anterior pituitary

Answer 2

Transported via the hypophyseal portal system

Question 3

What is the function of corticotropin releasing hormone (CRH)

Answer 3

Stimulates the corticotrophs of the anterior pituitary to produce adrenocorticotropic hormone (ACTH)

Question 4

What is the function of adrenocorticotropic hormone (ACTH)

Answer 4

Stimulates the zona fasciculata of the adrenal cortex to produce glucocorticoids e.g. cortisol

Question 5

Cortisol exhibits diurnal variation i.e. the plasma concentration of cortisol levels vary during a 24 hour period.

At what time of the day does the cortisol levels reach its peak

Answer 5

In the morning

Question 6

Cortisol exhibits diurnal variation i.e. the plasma concentration of cortisol levels vary during a 24 hour period.

At what time of the day does the cortisol levels reach its lowest point

Answer 6

At night

Question 7

What is the function of cortisol

Answer 7

Glucocorticoid - increases glucose levels

Exerts negative feedback on the release of both ACTH and CRH