Lecture #19 Low Circulating Calcium Response - MC

Question 1

What is the role of PTH when calcium levels are low in the bloodstream?
A) It reduces calcium reabsorption in the kidneys.
B) It inhibits calcium absorption in the intestines.
C) It stimulates the liver and kidneys to produce active forms of vitamin D.
D) It decreases the activity of osteoclasts in the bone.

Answer 1

C

Question 2

What is the function of calcitriol in calcium homeostasis?
A) It decreases calcium absorption in the gut.
B) It increases calcium reabsorption in the kidneys.
C) It stimulates the liver to produce less active vitamin D.
D) It activates osteoblasts to deposit calcium into the bone.

Answer 2

B

Question 3

Where does PTH stimulate the production of 25-OHD3, the first step in the activation of vitamin D?
A) Intestines
B) Bone
C) Liver
D) Kidney

Answer 3

C

Question 4

What effect does calcitriol have on the intestine?
A) It decreases the expression of calcium transporters.
B) It stimulates the expression of calcium transporters, enhancing calcium absorption.
C) It has no significant effect on calcium absorption.
D) It inhibits the activity of intestinal enzymes.

Answer 4

B

Question 5

What action does PTH have on the bones when calcium levels are low?
A) It activates osteoblasts to form new bone.
B) It deactivates osteoclasts to prevent bone resorption.
C) It activates osteoclasts to release calcium into the bloodstream.
D) It has no direct effect on bones.

Answer 5

C