Physiology of Adrenal Gland Flashcards Preview

SF3-EXAM 4 (CAMELITA) > Physiology of Adrenal Gland > Flashcards

Flashcards in Physiology of Adrenal Gland Deck (34)
Loading flashcards...
1

Which hormone is required to stimulate norepinephrine to epinephrine?

Cortisol

2

Which amino acid is norepinephrine stimulated from?

Tyrosine-> Dopamine-> Norepinephrine

3

Which substances are assessed in urine to clinically assess the level of catecholamine production in a patient?

Vanillylmandelic acid (VMA) and metanephrine

4

Adrenal catecholamines are methylated by _______ in nonneuronal tissues such as the liver and kidney.

Catechol-O-methyltransferase (COMT)

5

Pheochromocytoma

Benign tumor of the adrenal gland

6

What factors can stimulate release of epinephrine?

Anxiety

Pain

Trauma

Hypovolemia

Hypoglycemia

Hypothermia

 

7

Catecholamines require ________ and _______ to exert their full effects. 

Thyroid hormone; cortisol

8

Epinephrine and norepinerphrine ____________  (increase/decrease) blood flow to muscles.

Increase

9

Epinephrine promotes _____________ (glycogenesis/glycogenolysis) in muscle.

Glycogenolysis

10

Epinephrine and norepinephrine stimulate glucogon secretion and inhibit insulin secretion. Which receptor is used carry out each action, respectively?

B2: Stimulate glucagon secretion

A2: Inhit insulin secretion

11

Catecholamines cause ___________ (relaxation/constriction) of bronchiolar smooth muscle.

Relaxation

*They also act to decrease energy demand by visceral smooth muscle

12

Pro-opiomelanocortin (POMC) is a precursor for which hormones? What is the function of each?

α-MSH 

  • regulation of appetite
  • production of melanin.

ACTH

  • regulates the secretion of glucocorticoids from the adrenal cortex.

β-Endorphin and Met enkephalin

  • endogenous opioid peptides with widespread actions in the brain.

13

What are the major effects of cortisol at normal levels?

  • Stimulates:
    • Gluconeogenesis
      • Induces synthesis enzymes involved in hepatic gluconeogenesis
    • Protein catabolism
      • To provide substrate for glucogenesis​
    • Lipolysis
      • In adipise
    • Inhibition of insulin-stimulated glucose uptake by muscle and adipose tissue

REMEMEBER: Cortisol is considered a diabetogenic hormone

14

Physiological actions of glucocorticoids 

15

Cortisol inhibits ______ that is activated in response to injury.

Prospholipase A2

16

Cortisol decreases ______ migration to the site of injury.

Leukocyte

REMEMBER: Cortisol has immunosuprressive activity

17

What are the different types of causes of Cushing's syndrome? 

ACTH-dependent

  • Cushing's disease (pituatary dependent)
  • Ectopic ACTH syndrome
  • Ectopic CRH syndrome

ACTH-independent

  • Adrenal adenoma and carcinoma
  • Iatrogenic

Pseudo-cushing's syndrome

  • Alcoholism
  • Depression
  • Obesity

18

What are the major signs and symptoms of Cushing's syndrome?

Central obesity

Increased body weight

Fatigabilty and weakness

Hypertension

Hirtuitism

Amennorhea

Cutaneous striae

Personality changes

Ecchymoses (bruises)

Proximal myopathy

Edema

19

What are the symptoms that are more specific to Cushing's syndrome?

Central obersity

Hirsuitism

Amenorrhea

Cutaneous striae

Ecchymoses

Proximal myopathy

20

Dexamethasone suppresion test

  • Assess the pituatary corticotroph cell response to glucocoticoid negative feedback on ACTH secretion.

NOTE: Dexamethasone is potent glucocorticoid, about 30 to 40 times more potent than cortisol 

21

How should the following results be interpreted?

  • Low dose dexamethasone administered
  • Decrease in cortisol levels

Normal

22

How should the following results be interpreted?

  • Low dose dexamethasone administered
  • Cortisol is not suppressed by low doses
  • ACTH is undetectable or low

Cushing's syndrome (primary hypercortisolism)

  • Cortisol is being released in high levels so even with feedback from the dexamethasone to the hypothalamus and pituatary, one small dose is not enough to lower cortisol levels.

23

How should the following results be interpreted?

  • High dose dexamethasone administered
  • Cortisol is not suppressed by low doses, but is suppressed by high doses
  • ACTH is normal to elevated

Cushing's disease (Secondary hypercortisolism)

  • Likely a pituatary adenoma
  • ACTH is elevated

24

How should the following results be interpreted?

  • High dose dexamethasone administered
  • Cortisol is not suppressed by high or low doses
  • ACTH is elevated into hundreds

Ectopic ACTH syndrome 

 

25

What effect does aldosterone have on the following molecules?

Sodium, Potassium, Hydrogen Ion, Bircarbonate, Water

  • Sodium
    • increases reabsorption
  • Potassium
    • Increases secretion in colelcting duct
  • Hydrogen Ion
    • Increases secretion by intercalated cells of the collecting duct
  • Bircarbonate
    • Produces 
  • Water
    • Reabsoption

26

Which hormones stimulate Na+/K+ ATPase in reponse to the rise in plasma K+

Insulin, aldosterone, and epinephrine

NOTE: These hormones also stimulate Na+/K+/Cl= symporter and the Na+/Cl- symporter to increases cellular uptake. The kidneys then excrete excess K+

27

How do high plasma potassium levels stimulate aldosterone secretion?

Increase in plasma K+ depolarizes the plasma membrane and opens voltage-gated Ca+ channels leading to steroidogenesis in the glomerulosa of the adrenal cortex

28

___________ binds to receptors in the zona glomerulosa and inhibits the synthesis of aldosteron.

ANP

REMEMBER: ANP is released by the cardiac atrial muscle fibers in response to expansion of blood volume. It causes small increases in GFR and decreases sodium reabsorption at the collecting ducts

29

Addison's disease

  • The adrenal glands do not produce enough steroid hormones.
    • Low cortisol
    • Low aldosterone

30

What are the causes of adrenal insuffiency?

  • Primary
    • Destruction of gland
    • Metabolic
      • Congenital adrenal hyperplasia
  • Secondary
    • Hypothalamic-pituatary disease
    • Suppression of HPA- exogenous steroids