Adrenal Glands

Question 1

Types of adrenal glands

Answer 1

• adrenal cortex (endocrine gland)

- adrenal medulla (neuroendocrine organ, part of the SNS)

Question 2

Adrenal cortex (outer)

Answer 2

-three layers secrete different hormones
>outermost layer produces mineralcorticoids (aldosterone), which regulates [Na+] and [K+]
>middle layer produces glucocorticoids (cortisol), keeping blood glucose levels constant
>inner layer produces gonadocorticoids (sex hormones)
~converts to androgens, which some convert to estrogen (sexual characteristics, limited amounts made throughout life)

Question 3

Aldosterone

Answer 3

-increases H2O absorption
-reduces Na+ excretion
>enhances Na+ reabsorption by distal kidney tubules
>promotes Na+ retention from sweat
-promotes K+ excretion, triggered by:
> decrease in BV or BP
> increased [K+]
> ACTH and stress (long-term stress response)
-production inhibited by atrial natriuretic peptide (ANP), or hormone produced by the heart when BP is too high

Question 4

Cortisol

Answer 4

• glucocorticoids part of long-term stress response (increased output during trauma)
• promotes building of glucose from lipids
• increase blood glucose levels (hyperglycaemic hormone)
• promotes use of lipids as energy source (diverts glucose to the brain)
• high levels inhibit bone formation and inflammation, depress immune system, disrupt normal digestive, neural, and heart function
• released in response to increased ACTH levels in the blood

Question 5

Adrenal medulla

Answer 5

-modified neurons that make two similar catecholamines from tyrosine: (NE and E)
-both secreted to short-term stress response and:
> increases BP and HR
> dilates pulmonary and skeletal muscles of BV
> constricts visceral organ BV
> dilates bronchioles
> increases glucose levels