Lecture 25 (adrenal glands)

Question 1

Adrenal gland (structures + basic purpose)

Answer 1

Structures:
- capsule
- adrenal cortex*
- zona glomerulosa (salt) *most superficial
- zona fasciculata (sugar)
- zona reticularis (sex) *deepest
- adrenal medulla
*GFR- Glomerular Filtration Rate (helps remember)

Question 2

Hormones produced in adrenal gland and where

Answer 2

Adrenal cortex:
- ZG: aldosterone (a mineralocorticoid) Salt
- ZF:glucocorticoids (cortisol, cortisone, corticosterone) Sugar
- ZR: dehydroepiandrosterone/DHEA (weak androgen) Sex
Adrenal medulla:
- NE (20%) and E (80%)

Question 3

aldosterone effects

Answer 3

• signals kidneys to reabsorb Na+, increasing blood Na+ levels
• signals kidneys to excrete K+ through urine
• causes absorption of water into kidneys + blood
• increases blood pressure + volume

Question 4

angiotensin regulation (first half of aldosterone regulation)

Answer 4

renin-angiotensin-aldosterone pathway (RAA)
Blood:
- dehydration, Na+ deficiency or hemorrhage causes
- decrease in blood volume + pressure
Kidneys:
- juxtaglomerular cells in kidneys detect BP
- increase renin (enzyme)
Liver:
- releases angiotensinogen
- renin converts it to angiotensin I
Lungs:
- angiotensin converting enzyme (ACE) –> angiotensin II
A2:
- vasoconstriction increases BP

Question 5

second half of aldosterone regulation

Answer 5

renin-angiotensin-aldosterone pathway (RAA)
Adrenal cortex:
- angiotensin II or increased K+ levels trigger
- aldosterone production
Kidneys:
- effects of aldosterone increase blood volume and blood pressure

Question 6

glucocorticoid effects

Answer 6

• promote protein breakdown
• enhance lipolysis (fat break)
• produce glucose
• resistance to stress
• anti-inflammatory
• immunosuppressive

Question 7

cortisol regulation

Answer 7

Hypothalamus:
- low cortisol levels in blood OR stressors trigger
- CRH release
APG:
- ACTH (corticotropin) release
Adrenal cortex:
- cortisol release
high cortisol inhibits proper functioning of hippocampus, inhibits CRH and ACTH

Question 8

dehydroepiandrosterone/DHEA effects

Answer 8

• in XY, much less DHEA than testicular androgen
• in XX, contribute to libido and some converted to estrogens
• in menopause, contribute most estrogen

Question 9

DHEA regulation

Answer 9

Hypothalamus:
- stimulus trigger
- CRH release
APG:
- ACTH (corticotropin) release
Adrenal cortex:
- DHEA release
*no negative feedback from androgens
(means any triggers/inhibitors for CRH effect this)

Question 10

adrenal medulla (what it is)

Answer 10

modified sympathetic ganglion (of ANS)

Question 11

stress response

Answer 11

• alarm phase: epinephrine (immediate effects) + cortisol (slow effects) released
• adaptation: cortisol is elevated to adapt or resist (suppresses non-essential functions, SLUDD, immune, growth, reproduction)
• exhaustion: can lead to illness/death

Question 12

stressors (examples)

Answer 12

• thoughts, emotions, somatosensations (pain)
• hot or cold environment
• toxins or infections
• hemorrhage
• essentially anything that disrupts internal homeostasis

Question 13

good stress vs bad stress (name)

Answer 13

eustress (short/good emotion stress) vs distress (long/bad emotion stress)

Question 14

adrenal gland pathology (names + basics)

Answer 14

• Cushing’s syndrome (excess cortisol)
• Addison’s disease (deficient cortisol and aldosterone)
• Congenital adrenal hyperplasia (excess androgens)

Question 15

Cushing’s syndrome

Answer 15

• excess cortisol
• caused by tumor, adenoma or glucocorticoid administration
• increases size of adrenal gland
  Symptoms:
• muscle atrophy
• redistribute fat (to face, shoulder blades…)
• weight gain (cortisol increases appetite)
• hypertension
• osteoporosis
• susceptibility to infection
• pour wound healing

Question 16

Addison’s disease

Answer 16

• cortisol and aldosterone deficiency (adrenocortical insufficiency)
  Causes:
• autoimmune disease (destroy adrenal cortex or block ACTH)
• adrenal dysfunction (developed wrong)
• lack of CRH or ACTH
• withdrawal from meds
  Symptoms:
• weight loss
• hypoglycemia
• weakness
• decreased blood Na+ (hyponatremia), increased blood K+ (hyperkalemia)
• dehydration
• hypotension
• cardiac arrhythmias

Question 17

Adrenal hyperplasia

Answer 17

• rare, recessive autosomal disorder
• enzyme deficiency (cannot produce cortisol or aldosterone) causes hypersecretion of androgens
  Symptoms:
• XY, premature development (pubertyish) + severe illness within days of birth
• XX, virilization (‘male characteristics’)