skeletal 3

Question 1

what are the two ways of ossification

Answer 1

Intramembranous and endochondral.

Question 2

describe intermembranous ossification

Answer 2

Largely during foetal development
Bone is formed in sheets of connective tissue (collagen)
there the ossification center is formed as well as the trabeculae and the periostem. finaly the cranial flat bones, clavicles and part of the mandible.

Question 3

describe endochondral ossification

Answer 3

later in foetal development this process increases bone length. new bone is grown in cartilage framework. the steps goes as follows
1. cartilage model is developed.
2. development of the primary and secondary ossification center.
3. Formation of articular cartilage and epiphyseal plate
this porcess also occurs during regular development/ growth

Question 4

what process aid in bone growth

Answer 4

endochondral ossification

Question 5

how do bones grow

Answer 5

Growth in length via production of new cartilage by chondrocytes in epiphyseal plate
Epiphyseal plate widens = bone lengthens
Chondrocytes die
Osteoblasts replace chondrocytes and lay down bone
Epiphyseal plate closure occurs at the end of puberty

Question 6

Growth hormone

Answer 6

Stimulates release of IGF-1
IGF-1 stimulates chondrocyte proliferation = bone length

Question 7

Sex hormone

Answer 7

Cause increased growth during puberty
Cause epiphyseal plate to ‘close’, so further growth isn’t possible

Question 8

Thyroxine

Answer 8

required for skeletal mineralisation