bones

Question 1

which site is preferred for bone marrow transplantation

Answer 1

iliac cret

Question 2

where does red bone marrow persist into adulthood

Answer 2

spongy bones of vertebrae, ribs, sternum, cranium and epiphyses of long bones

Question 3

what is the role of sclerostin

Answer 3

inhibits bone growth

Question 4

which mab for osteoporosis? what does it do

Answer 4

romosozumab - inhibits sclerostin

Question 5

osteoclasts dissolve hydroxyapatite by pumping acid onto it. how do they maintain their own intracellular pH

Answer 5

also peeing out HCO3- from the “back side”

Question 6

what enzymes complete the hydrolysis of matrix proteins during bone resorption

Answer 6

Cathepsin K and collagenases

Question 7

osteoblasts secrete… what is it

Answer 7

osteoid - unmineralised bone cement

Question 8

what do osteoblasts become and where do they live

Answer 8

osteocytes, in lacunae

Question 9

Answer 9

A - osteoblast
B - osteocyte
C - unmineralised osteoid
D - cement line
E - mineralized bone

Question 10

what regulates elimination of phosphate via the kidneys, which directly impacts on the calcium balance

Answer 10

FGF23

Question 11

what lowers plasma Ca levels by directly inhibiting oscteoclast activity

Answer 11

calcitonin

Question 12

what sort of parathyroidism do you get with renal failure

Answer 12

secondary hyperparathyroidism

Question 13

drug used in treating secondary hyperparathyroidism in patients with chronic renal failure on dialysis. moa

Answer 13

cinacalcet
allosterically sensitises CaSR receptor, leading to less parathyroid secretion

Question 14

2 brand names for cinacalcet

Answer 14

sensipar
mimpara

Question 15

where does the last hydroxylation of vit D take place

Answer 15

PCT

Question 16

what stimulates the last hydroxylation of vit D

Answer 16

PTH

Question 17

what inhibits the last hydroxylation of vit D

Answer 17

calcitriol, FGF23 and/or phosphate

Question 18

how does vit D induce the precipitation of Ca and phosphate in osteoid

Answer 18

raising the concentrations in plasma above the solubility maximum

Question 19

how does calcitriol help stop fractures

Answer 19

increases formation of collagen 1 by osteoblasts

Question 20

where is the central target organ of calcitriol. why

Answer 20

duodenum, increase absorption of Ca

Question 21

what is the overriding effect of FGF23

Answer 21

reduces serum phosphate levels

Question 22

what happens in gain of function FGF23 mutation in a baby

Answer 22

hypophosphataemic ricketts

Question 23

what happens if you get paraneoplastic FGF23 GOF mutation

Answer 23

tumour-induced osteomalacia

Question 24

what happens if FGF23 doesn’t work

Answer 24

hyperphosphatemic familial tumoral calcinosis. extra calcium deposits everywhere. very bad

Question 25

which X-linked gene can cause hypophostphataemia

Answer 25

PHEX

Question 26

which enzyme does the final hydroxylation of vit D

Answer 26

1-alpha-hydroxylase

Question 27

lack of thyroid hormone in children causes

Answer 27

dwarfism

Question 28

hyperthyroidism effect on bones

Answer 28

osteoporosis

Question 29

FSH stimulates which bone cell activity

Answer 29

osteoclast