Lecture 4

Question 1

Adrenal gland

Answer 1

bodys adaptive response to stress, H2O, Na+ and K+ balance and BP regulation

Question 2

types of steroid hormones

Answer 2

mineralocorticoids, glucocorticoids and androgens

Question 3

Adrenal medulla

Answer 3

activated by preganglionic sympathetic neurons and rapidly releases catecholamines (adrenaline and noradrenaline) as part of the fight or flight response. It acts immediately during stress, independently of the pituitary gland. The medulla is derived from chromaffin cells, which are modified postganglionic sympathetic neurons. Although the adrenal medulla functions independently of cortisol, cortisol enhances catecholamine synthesis by upregulating enzymes involved in their production.

Question 4

chromaffin cells

Answer 4

cells that produce neurohormones and are found in the adrenal glans in groups of ganglia

Question 5

Steroid hormones secreted by adrenal cortex

Answer 5

glucocorticoids, mineralocorticoids, progesterone, androgens and estrogens

Question 6

glucocorticoids

Answer 6

control body’s response to stress, regulate glucose metabolism (cortisol

Question 7

Mineralocorticoids

Answer 7

Helps control H2O and electrolyte homeostasis (aldosterone) through Renin-angiotensin-aldosterone system

Question 8

Renin-angiotensin-aldosterone system

Answer 8

Liver always synthesises a precursor (angiotensinogen) which is an inactive form of enzyme so that response is immediate. When BP and fluid volume decrease, renin is secrete into the bloodstream causing precursor to form an immediate molecule (still not active). When angiotensin I passes through lungs and encounters ACE, it forms angiotensin that is active. Angiotensin II acts on target orfans to reestablish homeostasis.

Question 9

Adrenal androgens

Answer 9

secreted in response to ACTH by the anterior pituitary. have minimal role in stress response. Sex steroid hormones with weak androgenic activity. Provide a pool of circulating precursors for peripheral conversion into potent androgens (low levels), testosterone and estrogen. In males, promote growth and help in development of masculinisation and libido. In females also promote libido, hair growth and sebum production