University:
MacEwan University
Course:
HLSC 120 | Human Anatomy
Academic year:

2023
Views:

237

Pages:

2
Author:

Arthur M.

1) GROWTH IN LENGTH (Interstitial Growth). Epiphyseal plate cartilage Closest to epiphysis inactive *Cells closer to diaphysis. organize in pattern that allows for fast, eff. growth Zones: 1) Proliferation (growth) -Cartilage cells divide, push epip a.fro. diap. 2) Hypertrophic "Old cartilage cells enlarge 3) Calcification -Matrix calcified, cart. cells. die, matrix deteriorates 4) Ossification (osteogenic) - New bone forms aS osteoblasts secrete bone matrix onto calcified cartilage Spicule (spike) Calcified cartilage spicule Osteoblast depositing- bone matrix Osseous tissue- (bone) covering cartilage spicules Resting zone ① Proliferation zone Cartilage cells undergo mitosis. ② Hypertrophic zone Older cartilage cells enlarge. ③ Calcification zone Matrix becomes calcified; cartilage cells die; matrix begins deteriorating. ④ Ossification zone New bone formation is occurring. Growth Articular cartilage Remodeling Growing shaft is remodeled ty: Bone grows in length because: Cartilage- grows here Cartilage replaced by bone here Cartilage grows here Cartilage replaced by bone here 2) GROWTH OF EPIPHYSES "Occurs in similar way to keep pace with growth of diaphysis (cartilage continually grows & is replaced by bone) Growth of spongy bone (interstitial growth) C. Hormonal Reg. of Bone Growth (Youth) Infancy/childhood -Epiphyseal plate activity stim. by growth hormone During Puberty, testosterone and estrogens: Initially promote adolescent growth spurts "Cause masculinization or feminization of specific parts Induce epiphyseal plate closure, end longitudinal bone gr. bone matrix on outer Surface appositionalg, Osteoclasts remove bone from inner surface to widen shaft) (Osteoblasts deposit Bone both formed & resorbed to remodel bone & increase width 3) GROWTH IN WIDTH Bone resorbed here Epiphyseal plate Bone resorbed here 2 Bone added by appositional growth here