Parathyroid Glands and Physiology of Bone

Calcium in Bones

Actions of 1,25- Dihydroxycholecalciferol

Parts of structure of long bone

Supongy Bone

Bone Resorption-Osteoclastic Activity

Bone Gormation –Osteoblastic Activity

Mineralization

A 36-year-old woman has a parathyroid hormone (PTH)-secreting tumor. Which of the following might be expected to increase as a result of chronic PTH elevation?

◦ Bone resorption *◦ Bone deposition ◦ Ca2+ excretion from the intestines ◦ PO4

3+ absorption from the intestines

◦ PO43+ reabsorption from the kidneys

The normal serum calcium level is ___mg/100 ml?

a) 4-6

b) 6-8

c) 9-11

d) 14-16

Normal daily calcium excretion in urine is ___mg?

a) 50

b) 100

c) 200

d) 300

For calcium metabolism, all of the following are required except?

a) vitamin D

b) parathyroid hormone

c) calcitonin

d) thyroxine

cholecalciferol is?

a) vitamin D3

b) precursor of vitamin D3

c) occurs in skin

d) physiologically active

The active form of vitamin D is?

a) calcium

b) 1,25 DHCC

c) parathyroid hormone

d) cholecalciferol

The primary site of 1,25 DHCC formation from its immediate precursor is?

a) bone

b) liver

c) kidney

d) skin

The following statement about calcium absorption from small intestine are true except?

(A)It occurs by active transport. (B) It requires vit. D and parathormone. (C)It occours by passive diffusion from

upper small intestine. (D)It is decreased by excess phosphate and

oxalate in food