Adrenal Glands Flashcards Preview

Term II: Endocrinology > Adrenal Glands > Flashcards

Flashcards in Adrenal Glands Deck (28)
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1
Q

What are the functions of the adrenal cortex?

A

Salt and fluid volume homeostasis, adjust metabolism, immune modulation, minor sex steroids production

2
Q

What is the function of the adrenal medulla?

A

“Fight of flight” junction between CNS and rest of tissue

3
Q

Name pathway of glucocorticoid production.

A

Hypothalamus –> CRH –> Corticotrophic cells in Ant. Pit. –> ACTH –> Adrenal cortex –> Glucocorticoids

4
Q

What is the only peptide hormone that activates the hypothalamus-adrenal axis?

A

CRH

5
Q

What large peptide is ACTH cleaved off of?

A

POMC

6
Q

What type of signaling pathway does CRH work through?

A

Gs – CAMP – PKA – synthesis of POMC mRNA

7
Q

Does the adrenal cortex store pre-formed glucocorticoids and mineralocorticoids like the corticotrophic cells of the anterior pituitary?

A

No - the entire process of hormone (cortisol) synthesis is de novo

8
Q

What molecule is the adrenal cortex rich in? (makes it yellow)

A

Lipid droplets that are filled with cholesterol

9
Q

What is significance of cholesterol in adrenal cortex?

A

ACTH stimulus results in cholesterol release, which allows steroidogenic enzymes to be translated and sent to mitochondria so SER can make them a hormone

10
Q

What hormone provides the main negative feedback for the adrenal cortex?

A

Cortisol

11
Q

What are the three zones of the adrenal cortex?

A

zona glomerulosa, zona fasciculata, zona reticularis

12
Q

What hormones does the zona glomerulosa make? What enzyme does it use to do so?

A

Mineralocorticoids (Aldosterone)

18-hydroxylase

13
Q

What hormones do the zona fasciculata make? What enzyme do they use?

A

Glucocorticoids (cortisol), sex steroids

17-hydroxylase

14
Q

What regulates aldosterone production in zona glomerulosa?

A

RAAS system, rise in potassium, ACTH (but minor effect)

15
Q

What hormones do the zona reticulate make?

What enzymes does it use?

A

Sex hormones

17,20 lyase

16
Q

What happens to ACTH levels if cortisol decreases?

A

ACTH levels increase (b/c there is no negative feedback)

17
Q

How are steroid hormones transported in the blood?

A

bound to cortisol binding globulin (CBG) and albumin

18
Q

What is the end product of sex steroids that is excreted?

A

17-hydroxysteroids

19
Q

What is the end product of glucocorticoids that is excreted?

A

17-ketosteroids

20
Q

What defines glucocorticoid activity?

A

Ability to mobilize glucose

21
Q

What defines mineralocorticoid activity?

A

Ability to reabsorb sodium

22
Q

How do renal tubular cells deal with high cortisol levels?

A

Since aldosterone and cortisol normally have opposite effects, but share the same receptor, renal tubular cells convert cortisol to cortisone (less potent) so that sodium reabsorption stays dependent on aldosterone levels, not cortisol levels

23
Q

How do glucocorticoids exert their effects on cells? (hint: what type of hormone are they?) How long is the response?

A

Steroid hormones - bind to nuclear receptors and induce gene transcription; response can last over hours

24
Q

What effects do glucocorticoids have?

A
  1. Metabolic - primes body for fasts, so proteolysis, gluconeogenic enzyme expression, lipolysis
  2. Anti-inflammatory - inhibits phospholipase-A2, kills immature T and B cells
  3. Stress
25
Q

What types of receptors does adrenal medulla use for its effects?

A

Alpha and beta-mediated

26
Q

What is the adrenal medulla’s response to hypoglycemia?

A
  1. MUSCLE & FAT: glycogenolysis, glycolysis, lactate
  2. LIVER: gluconeogenesis, glycogenolysis
  3. FAT: lipolysis
  4. PANCREAS: suppression of insulin and stimulation of glucagon
27
Q

What is Cushing’s syndrome?

A

Hypercortisolemia (excess glucocorticoids)

- can result from hypothalamic, pituitary, or adrenal cortex tumors

28
Q

What is Addison’s syndrome?

A

Hypocortisolemia (lack of glucocorticoids) - patients can be tan