Chapter 5: Cartilage

What is cartilage?

• chondroblasts in lacunae of growing cartilage;

• lacks nerve fibers and is avascular, so it heals slowly

• Aging cartilage cells lose their ability to divide

  • Older cartilage tends to calcify and even ossify

• matrix made of chondroitin sulfate, hyaluronic acid, and collagen fibers

• resists tension and compression because it is 80% water

What are the types of cartilage?

hyaline, elastic, fibrocartilage, bone, blood

Hyaline

S: uniform collagen fibers in matrix for a glossy or glass-like appearance

F: firm support with some pliability

L: ends of long bones, tip of nose, costal cartilage (between sternum and ribs), respiratory passages, embryonic skeleton and epiphyseal plate

Elastic

S: matrix has more elastic fibers than hyaline cartilage

F: gives strength and exceptional stretchability

L: found in external ear (pinna) and epiglottis

Fibrocartilage

S: chondrocytes in rows that alternate with collagen

F: resist heavy pressure and tension

L: between vertebrae, pubic bones, and forms meniscus of knee

What is bone?

osteocytes imbedded in a mineral matrix, in an orderly arrangement called osteons

What is blood?

formed elements (cells called erythrocytes (RBC’s), leukocytes (WBC’s) and thrombocytes (platelets)) in a fluid matrix