bone development

Question 1

ow do skull bones form

Answer 1

intrmembranous ossification

Question 2

which other bones other than skull bones form my intramembranous ossifictaion

Answer 2

mandible and part of clavicle

Question 3

which is first bone to form and last to ossify

Answer 3

clavicle

Question 4

how do IO bones form

Answer 4

directly from mesenchymal stem cells-> osteoblasts->osteocytes

Question 5

what is the name when there is a cartilaginous template within which bone is laid down

Answer 5

endochondral ossification

Question 6

which is the first part of a long bone to ossify

Answer 6

bone collar

Question 7

what is a secondary ossification site

Answer 7

above epiphyseal growth plate

Question 8

what is the name of the lacuna made by osteoclasts

Answer 8

HOWSHIP LACUNA

Question 9

condition wherein there is too much woven bone

Answer 9

Paget’s disease

Question 10

why appositional growth

Answer 10

to remove excess mass and strengthen bone

Question 11

where is cortical bone densest

Answer 11

most loadbearing point in diaphysis

Question 12

name of mineral crystals in bone

Answer 12

hydroxyapatite

Question 13

what is normal serum Ca2+

Answer 13

2.2-2.6mmol/l

Question 14

what 2 things do osteoclasts seceret

Answer 14

hcl, protein digesting enzymes

Question 15

what is the final pathway when serum ca2+ is very low

Answer 15

Parathyroid hormone secreted-> osteoblast PTH receptor->RANKL expressed-> ++osteoclasts activated-> Ca2+ reabsorbed from bone

Question 16

what are the 3 things PTH does

Answer 16

suppress kidney Ca2+ excretion, attach to osteoblast PTH receptor ->rankl -> ca2+ resorbtion from bone, kidneys synthesise more cholecalciferol -> more gut absorption of ca2+

Question 17

what inhibits motiltiy of osteoclasts

Answer 17

calcitonin

Question 18

what do oestrogen and progesterone do re bone

Answer 18

+blas -clast

Question 19

danger of glucocorticoids (corticosteroids )

Answer 19

osteoporosis