1. Cartilage

2. Functions: ◘ Support soft tissues (nose, ear, trachea).
◘ Shock-absorbing and sliding areas for joints, facilitate bone movements.
◘ Essential for the development and growth of long bones.

3. Structure Structure Cells: chondrocytes Extracellular matrix fiber
ground substance

4. Cartilage composition
Cells
Chondrocytes: located within matrix; lacunae
Chondroblasts: located at periphery; secrete extracellular matrix
Fibers
Collagen and elastic fibers
Ground substance
Rich in glycosaminoglycans and proteoglycans

5. Cartilage composition
Perichondrium
Perichondrium is a layer of dense irregular connective tissue.
It is essential for the growth and maintenance of cartilage.

6. More Features of Cartilage
Avascular;
Nutrients diffusion from perichondrium or synovial fluid;
No innervation;
No lymphatic vessels;
Chondrocytes have low metabolic activity

7. Classification: Hyaline cartilage: most common, much type II collagen
Elastic cartilage: elastic fibers
Fibrocatilage: dense network of type I collagen
Properties of extracellular matrix

8. Hyaline Cartilage Blue-white and translucent distribution：
Joint surfaces, nose, larynx, trachea, bronchi, ends of ribs adjacent to sternum

9. Structure Cells: chondrocytes Extracellular matrix fiber
ground substance
Perichondrium
Perichondrium is a layer of dense irregular connective tissue.
It is essential for the growth and maintenance of cartilage.
Found around all HC except joint HC
Rich in fibroblasts, chondroblasts, blood vessels,
and nerves.

10. 1. Chondrocyte
(1) In hyaline cartilage, chondrocytes are distributed either singly or in cluster
lacunae：
isogenous nest：chondrocytes arranged in pair or group of four or six

11. (2) chondrocytes are specialized cells that produce and maintain the extracellular matrix

12. 2. Matrix
(1) Hyaline cartilage matrix is produced by chondrocytes and contains three major classes of molecules:
①Collagen molecules
②Proteoglycans
③Nocollagenous proteins
fiber—— mainly type Ⅱ collage fiber
ground substance

14. (2) Grounds substance components of hyaline cartilage matrix are not distributed uniformly
Capsusle/territorial matrix (TM)：
matrix surrounding each chondrocyte
Interterritorial matrix (IM)：
matrix between the territorial matrix

15. Elastic Cartilage Auricle of ear, external auditory canal, epiglottis
Similar to HC, many elastic fibers in the matrix
Perichondrium

16. Elastic cartilage

17. Fibrocartilage
Found in Intervetebral disks, tendon and ligament attachment to bone, symphysis pubis
Combination of HC and dense regular connective tissue
Chondrocytes often in rows or groups
Matrix acidophilic due to high collagen
No perichondrium

18. Fibrocartilage

19. summary Cartilage is a semi-rigid form of connective tissue
3 types of cartilage
structure of hyaline cartilage

20. Chapter 5. Bone

21. Overview of bone · Bone is a specialized form of connective tissue.
Cells
Extracellular matrix: mineralization
· Functions of bone:
Support: Provides attachment for tendons of skeletal muscles
Protection: Protects internal organs
Storage: calcium ,phosphate

22. Structure of bone 1. Matrix · Organic matter
endosteum：lined on internal surface
periosteum：lined on external surface
1. Matrix
· Organic matter
type I Collagen: 90%
Ground substance: 10%
· Inorganic matter（bone mineral）
The inorganic matter is calcium phosphate in the form of hydroxyapatite crystle [Ca10(PO4)6(OH)2]

23. 2. Cells
osteoprogenitor, osteoblast, osteocyte and osteoclast.

24. A. osteoprogenitor cell
-- Resting cell that can transform into osteoblast.
-- Found on the external and internal surfaces of bones.
-- Only bone cells that undergoes cell division, daughter cells becomes osteoblasts

25. B. osteoblast -- secretes organic compounds for bone matrix.
-- located at the surfaces of bone.

26. C. osteocyte -- mature cell and is enclosed by bone matrix
-- osteocytes are found in matrix.
Lacuna
Canaliculi

27. D. osteoclast -- responsible for bone resorption.
-- rest directly on bone where resorption is taking place.

29. 3.Types of bone
epiphysis
diaphysis
epiphysis
Structure of long bones

30. Compact bone Spongy bone --has no cavities.
--forms the outside of the bone.
Spongy bone
--has numerous interconnecting cavities.
--forms the interior of the bone.

31. Compact Bone
Functional Unit is the Osteon or Haversian System—concentric rings of lamellae around a Central Canal, with connecting Peripheral Canals

33. Compact Bone 1.osteon 2.outer circumferential lamellae
3.inner circumferential lamellae
4.interstitial lamellae

34. Histogenesis Intramembranous ossification: flat bone
Endochondral ossification: short and long bone

35. Intramembranous Ossification

36. Endochondral Ossification

37. Endochondral Ossification

38. Summary · Matrix: · Cells： · Structure of long bones
organic matter, inorganic matter and a little water
· Cells：
osteoprogenitor cell, osteoblast, osteocyte and osteoclast
· Structure of long bones
periosteum and endosteum, epiphysis, diaphysis
ossification

39. Questions: What’s the function of cartilage?
Review the structure of bone.
Describe the two processes of ossification.