Lecture 19 Calcium - MC

Question 1

Where is the majority of calcium in the body found?
A) In muscles and liver
B) In bones and teeth
C) In blood plasma
D) In the brain and nerves

Answer 1

B

Question 2

What percentage of dietary calcium is generally absorbed by the body?
A) 10-15%
B) 25-30%
C) 40-45%
D) 50-55%

Answer 2

B

Question 3

Which factor is known to enhance the absorption of calcium?
A) Fiber
B) Oxalic acid
C) Vitamin D
D) Phytic acid

Answer 3

C

Question 4

What is the primary mechanism by which calcium is absorbed in the small intestine?
A) Passive diffusion
B) Saturable, carrier-mediated active transport
C) Simple osmosis
D) Filtration through capillary walls

Answer 4

B

Question 5

What triggers the release of parathyroid hormone (PTH)?
A) An increase in plasma calcium levels above 10.5 mg/dL
B) A decrease in plasma calcium levels below 8.5 mg/dL
C) High levels of vitamin D in the blood
D) Low levels of magnesium in the blood

Answer 5

B

Question 6

What action does calcitonin have when calcium levels in plasma are too high?
A) It increases the activity of osteoblasts.
B) It increases the activity of osteoclasts.
C) It suppresses the release of PTH and inhibits the activity of osteoclasts.
D) It enhances the reabsorption of calcium in the kidneys.

Answer 6

C