Specialized connective tissue Rigid Elastic Resilient rebounds readilyelastic

• Specialized connective tissue • Rigid, Elastic, Resilient – (rebounds readily-elastic) RESISTS COMPRESSION • AVASCULAR – nutrients diffuse through matrix

Functions of Cartilage Tissue Specialized CT in which the firm consistency of the extracellular matrix allows the tissue to bear mechanical stresses without permanent distortion Supports soft tissues. Shock-absorbing because it is resilient. Smooth surface allows sliding against it. Essential for growth, development of bone.

Cartilage is a type of Connective tissue Contents: cells, fibers and ground susbtance Types of Fibers: Type I collagen (fibrocartilage) type II collagen (hyaline and elastic) Elastic fibers (elastic) Types of cells Chodroblasts condrocytes

1. CHONDROBLAST Progenitor (an ancestor in the direct line)of chondrocytes Lines border between perichondrium and matrix Secretes type II collagen and other ECM components

CHONDROCYTE Mature cartilage cell spherical in shape Nucleus_central, 2 or more nucleoli Cytoplasm__finely granular, basophilic

2. CHONDROCYTE Reside in a space called the lacuna Clear areas = Golgi and lipid droplets dissolve during routine staining.

Chondrocytes in Lacunae

Chondrocytes completely fill their lacunae Synthetically active, secrete matrix N RER Cartilage matrix

MATRIX Provides the rigidity, elasticity, & resilience FIBERS Collagenous and elastic GROUND SUBSTANCE Glycosaminoglycans (chondroitin sulfates, keratin sulfate, hyaluronic acid) Proteoglycans: GAGs + core protein Water Basophilic Territorial matrix -

PERICHONDRIUM Dense irregularly arranged connective tissue (type I collagen) Ensheaths the cartilage Contains the blood vessels that nourish chondrocytes

It is composed of two layers 1. FIBROUS LAYER. Outer layer collagen and elastic fibers, large blood vessels. 2. VASCULAR LAYER. Cartilage forming cells blood vessels, few collagen fibers

TYPES OF CARTILAGE HYALINE ELASTIC FIBROUS

HYALINE CARTILAGE Most widely distributed Bluish white color. Strong, rubbery, flexible tissue.

HYALINE CARTILAGE Hyaline__glass like appears clear fibers__not visible under microscope. CHONDROCYTES lacunae Isogenous groups MATRIX Type II collagen (thin fibrils) Chondroitin sulfate, keratin sulfate, hyaluronic acid Water Trritorial , inter territorial matrix Isogenous group

Cartilage looks like EYES LOCATION Tracheal rings, nasal septum, larynx, articular surfaces of joints ends of long bones,

HYALINE CARTILAGE Rubbery Translucent, glassy appearance. Covered by perichondrium except for large articular cartilage of synovial joints. Chondrocytes in lacunea isogenous groups Matrix__interterritorial, territorial Collagen fibers, chondrioten sulphate karaten sulphate, water.

Hy aline cartilage chondrocyte Elastic Cartilage

ELASTIC CARTILAGE Stucture is similar to hyaline cartilage but has elastic fibers running in all directions in addition to collagen. Maintains shape, deforms but returns to shape; flexibility of organ; strengths and supports structures.

ELASTIC CARTILAGE FUNCTION Support with flexibility MATRIX Normal components of hyaline matrix plus ELASTIC fibers LOCATION External ear, external auditory canal, epiglottis STAINS Elastic fibers stain BLACK with Weigert stain perichondrium

ELASTIC CARTILAGE

Elastic Cartilage Elastic fibers (elastin)

ELASTIC CARTILAGE Yellowish and more opaque Chondrocyte structuer is similar Elastic fibers Perichondrium

Fibrocartilage transitional between dense connective tissue and hyaline cartilage. Present wherever great strength and flexibilty is required. Chondrocytes may lie singly or in pairs, but most often they form short rows between dense bundles of collagen fibres. collagen type I is dominant in fibrous cartilage. the perichondrium ABSENT

Fibrocartilage Note the rows of chondrocytes separated by collagen fibers. Collagen fibers lie parallel to lines of stress Fibrocartilage is frequently found in the insertion of tendons on the epiphyseal hyaline cartilage.

FIBROCARTILAGE FUNCTION Support with great tensile strength LOCATION Intervertebral disks, pubic symphysis

How many types of cartilage do you see?

C A Questions 2 and 3: 2. The three tissues shown have all of the following properties in common EXCEPT: a. b. c. d. B They contain capillaries. They contain proteoglycans. They can increase in size by interstitial growth. They can increase in size by appositional growth. 3. Which tissue is the most highly specialized to resist compression? a. A b. B c. C