the growing skeleton W9

Question 1

2 types of ossification?

Answer 1

endochondral ossification
intramembranous ossification

Question 2

endochondral ossification features?

Answer 2

occurs on cartilage scaffold
most of the skeleton
the physis
fracture healing (cast)

Question 3

intramembranous ossification features?

Answer 3

embryonic flat bones
subperiosteal bone growth
fracture healing (plates/screws)

Question 4

types of bone?

Answer 4

woven
lamellar

Question 5

summary of growth occurring in physis?

Answer 5

chondrocytes transition through cascade of of stages, growing in number then size before undergoing apoptosis, to release stored calcium. osteoprogenitor cells invade calcium matrix, lay down woven bone, which is then remodelled to lamellar bone

Question 6

factors affecting final height?

Answer 6

genetics (race, parental heights, sex)
altering factors (systemic disease, nutrition, endocrine, infection, trauma)

Question 7

4 stages of growth? what are these stages mainly dependant on?

Answer 7

foetal - uterine environment (eg maternal diet)
infantile - nutrition, general health
childhood - genetics (parental height)
pubertal -

Question 8

what triggers the onset of puberty?

Answer 8

pulses of GnRH is released from the hypothalamus during the night, after time this is constantly released all times of day and night.
LH and FSH released from pituitary, causes gonads to release estrogens and androgens

Question 9

effects of testosterone?

Answer 9

bone density/growth increases (disproportionate - facial, shoulder width)
muscle mass - increases bulk and strength, doubled by end of puberty. occurs later in puberty

Question 10

effects of oestrogen?

Answer 10

fat distribution - buttocks, hips, thighs, facial subcutaneous fat, higher body fat
increased bone density, widened pelvis, anteverted hips