Bony Transision | Lecture Note

University:
The University Of Western Ontario
Course:
ANAT 2200B | Systemic Anatomy of the Human Body
Academic year:

2022
Views:

381

Pages:

2
Author:

Kyuwon J.

Low power view ● Epiphysis ⇒ metaphysis ○ Parallel vertical columns on chondrocytes ○ Arrangements = pathognomonic on endochondral ossifications ● Zone of Growth plates ○ Zone 1 ■ Resting cartilages ● Small, round chondrocytes ● Scattered randomly ● Large amount of matrix ● Mitosis ■ Fixed to growth plates ■ Cell reservoir ○ Zone 2 ■ Proliferations ● Chondrocytes in vertical columns ● Flatten cell ● Active dividing ○ Mitotic cells could be seen ● Basophilic ○ Proteoglycan rich ■ Responsible for longitudinal growths ○ Zone 3 ■ Hypertrophy ● Chondrocytes enlarged ● Lacunae widens ● Cytoplasm becomes pale ● Vacuolated cytoplasms ● Thinning in cartilage ■ Chondrocytes will go under apoptosis ■ Sensitive for ischemia + toxins ○ Zone 4 ■ Cartilage becomes basophilic ■ Dead chondrocytes ■ Lacunae empty ■ Thin septa ● Could see it as calcified cartilage remains ○ The matrix is calcified but this is not a bone ○ Zone 5 ■ Ossifications ● Invasion of blood vessels ● Osteoblasts will line calcified cartilages ● Deposited on cartilage remnants ● Women bone trabeculae ○ Osteoblast ○ Osteoclast ○ Capillaries are present MAJOR PATHWAY Resting → Proliferation → Hypertrophy → Calcification → Ossification (cartilage) (bone)