Download Endocrine 1. Regarding calcium metabolism a. Approximately 60

Endocrine
1. Regarding calcium metabolism
a. Approximately 60% of filtered calcium is reabsorbed by the kidney
b. Absorption of calcium in the gastrointestinal tract is mainly by passive diffusion
c. The extent of Ca@+ binding by plasma proteins is inversely proportional to the plasma protein
level
d. Levels of 1,25 dihydroxycholecalciferol fall in the presence of increased plasma Ca2+
e. The majority of calcium present in bone is readily exchangeable
2. regarding 1,25 dihydroxycholecalciferol (calcitriol)
a. it is formed by the action of sunlight on previtamin D3
b. it exerts its actions via stimulation of adenylyl cyclase
c. it decreases calcium reabsorption from kidneys
d. its formation is increased with elevated plasma Ca2+ levels
e. it causes increased formation of calbindin-D proteins
3. With regard to the effect of thyroid hormone on the cardiovascular system, which of the following is
TRUE?
a. Levels of noradrenaline are increased
b. Beta adrenergic receptor affinity is decreased in heart muscle
c. Circulating adrenaline levels are decreased
d. Thyroid hormone levels alter the ratio of cardiac myosin isoform types
e. None of the above
4. Insulin release
a. Is inhibited by raised cyclic AMP in pancreatic beta cells
b. Is not stimulated by blood glucose levels below 6mmol/L
c. Is increased by beta adrenergic stimulators
d. Is inhibited by phosphodiesterase inhibitors
e. Is increased by somatostatin
5. Which of the following does not act via an intracellular receptor?
a. Atrial natriuretic peptide
b. Cortisol
c. Thyroxine
d. Aldosterone
e. Retinoic acid
6. Atrial natriuretic peptide decreases formation of all of the following EXCEPT:
a. Aldosterone
b. Cyclic GMP
c. Renin
d. Vasopressin
e. Angiotensin III
7. Regarding the role of vitamin D in calcium metabolism, which of the following is INCORRECT?
a. It increases renal tubular calcium phosphate reabsorption
b. It causes an increase in synthesis of calcium-binding protein
c. It increases bone resorption
d. It decreases bone formation
e. It increases intestinal calcium and phosphate absorption
8. Insulin secretion is increased by
a. Thiazide diuretics
b. Glucagon
c. Potassium depletion
d. Adrenaline
e. Somatostatin
9. With regards to calcium regulation and metabolism
a. 98% of calcium is reabsorbed in the proximal tubule -98-99% reabsorbed, 60% PT, the rest TAL
and DT
b. the transport of calcium out of the intestine into the circulation involves a calcium dependent
ATPase
c. a decrease in plasma calcium level will decrease 1,25 dihydroxycholecalciferol level
d. calcium absorption is increased by high levels of phosphates and oxalates
e. distal tubule reabsorption is not regulated by parathyroid hormone – it is
10. Increased T4 and T3 levels
a. Casues CSF protein to increase
b. Causes O2 consumption of the thyroid to increase
c. Are not caused by starvation
d. Suppresses formation of LDL receptors
e. Delays epiphyseal closure
11. Renin secretion is inhibited by
a. Prostaglandins
b. Diuretics
c. Cardiac failure
d. Cirrhosis
e. Increased afferent arteriolar pressure
12. Glucose reabsorption by the kidney
a. Is independent of glucose load
b. Occurs in the distal convoluted tubule
c. Involves potassium reabsorption
d. Occurs through passive diffusion
e. Occurs through secondary active transport
13. Insulin
a. Is synthesized in the Golgi apparatus of beta cells
b. Is released mostly in its proinsulin form
c. Has a half-life of 50 minutes
d. Binds to intracellular receptors
e. Is motly degraded in the liver and kidneys
14. With regards to renin
a. Prorenin has the same activity as renin
b. It is a cleavage enzyme
c. ?
d. ?
e. ?
15. Hypothyroidism casues
a. Cretinism
b. Myxoedema
c. Early genital development
d. Hair loss
e. ?
16. Regarding thyroid hormones which is INCORRECT?
a. They increase plasma cholesterol – lower it due to increased LDL receptors and uptake into liver
b. They increase the activity of Na/K/ATPase
c. They increase the number/affinity of beta adrenergic receptors
d. They alter the proportion of alpha myosin heavy chains
e. They have a calorigenic action
17. Regarding Ca2+ metbolism, which is INCORRECT?
a. 1,25 dihydroxycholecalciferol is formed in the liver
b. PTH acts on the distal tubule to decrease phosphate absorption
c. ?
d. ?
e. ?
18. What factor decreases renin secretion?
a. Hypovolaemia
b. Supine position
c. Cardiac failure
d. Na depletion
e. ?
19. Insulin
a. Increases the number of glucose transporters on the cell surface
b. Regulates intracellular glucose metabolism
c. ?
d. ?
e. ?
20. With regard to cortisol, which is INCORRECT?
a. It is predominately metabolized in the liver
b. It has a permissive action on vascular reactivity
c. It has greater mineralocorticoid activity than glucocorticoid activity
d. ?
e. ?
21. A deficiency of parathyroid hormone is likely to lead to:
a. Hypophosphataemia
b. The formation of kidney stones
c. A self limiting illness
d. Neuromuscular hyperexcitability
e. Cystic bone disease
22. With regard to thyroid physiology
a. T3 and T4 are metabolized in the spleen and bone marrow
b. T3 and T4 bind and act at the same cell membrane receptor
c. T4 is synthesized from tyrosine held in thyroglobulin
d. T3 is bound to a complex polysaccharide in the plasma
e. T4 is more active than T3
23. Insulin
a. Is secreted by the A cells in the islets of Langerhans
b. Is a triple helical polypeptide
c. Is synthesized as a prohormone
d. Binds at cytoplasmic receptor sites
e. Causes K+ leak out of cells
24. Insulin secretion is stimulated by all of the following EXCEPT:
a. Mannose
b. Glucagons
c. Noradrenaline – and an infusion causes hyperglycaemia
d. Leucine
e. Acetylcholine
25. With regard to adrenal physiology
a. The only glucocorticoid secreted in significant amounts is cortisol
b. Dopamine is secreted by the adrenal medulla
c. The largest steroid molecules are the oestrogens
d. Cortisol has negligible mineralocorticoid activity
e. Glucocorticoids exert their action by cGMP activation
26. With regard to the renin-angiotensin system
a. Prorenin has 50% of the activity of renin
b. Renin secretion will be increased by propranolol
c. Angiotensinogen is synthesized in the liver
d. Angiotensin I is a potent vasoconstrictor
e. Angiotensin II acts at receptors in the nucleus
27. Atrial natriuretic peptide
a. Stimulates the secretion of vasopressin
b. Secretion will be decreased by scuba diving
c. Is a typical dual chain helix structure
d. Stimulates eryhtropoietin production
e. Has generally opposite actions to angiotensin II
28. Which of the following does not utilise the same receptor in its mechanism of action?
a. Insulin – tetramer, activates t-kinase
b. Glucagon – G protein coupled
c. PTH – G protein coupled
d. ACTH - G protein coupled
e. They all have the same mechanism of action
29. Regarding glucagons
a. It is secreted by the pancreatic B cells
b. It increases glycogen formation
c. It has a half life of 30 minutes
d. Secretion is stimulated by glucose
e. It stimulates insulin secretion
30. Regarding insulin
a. It increases protein catabolism in muscle
b. Secretion is inhibnited by somatostatin
c. Secretion is stimulated by phenytoin
d. It casues decreased K+ uptake into adipose tissue
e. It causes decreased protein synthesis