Supporting Connective Tissues

Types of Supporting Connective Tissue

cartilage and bone

cartilage

-matrix is a firm gel

-avascular because chondrocytes produce a chemical that discourages the formation of blood vessels

chondrocytes

-cartilage cells

-only cells found in cartilage matrix

lacunae

small chambers that chondrocytes live in

perichondrium

-fibrous

-separates cartilage from surrounding tissues

-outer layer- fibrous layer of dense irregular CT

-inner layer- cellular layer

fibrous layer of perichondrium

-provides mechanical support and protection and attaches the cartilage to other structures

cellular layer of perichondrium

important to the growth and maintenance of cartilage

appositional growth

-stem cells of inner layer of perichondrium undergo repeated cycles of division

-innermost cells differentiate into chondroblasts which produce cartilage matrix

- chondroblasts differentiate into chondrocytes and adds to the cartilages surface

interstitial growth

-chondrocytes wishing cartilage matrix undergo division and their daughter cells produce additional matrix

-this cycle enlarges the cartilage from within

Types of Cartilage

hyaline, elastic, fibrous

hyaline cartilage

-most common type of cartilage

-matrix contains closely packed collagen fibers

-weakest type of cartilage

-provides stiff but somewhat flexible support

-reduces friction between bony surfaces

-examples: connection between ribs and sternum, supporting cartilages on along the conducting passageways of the respiratory tract, and the articular cartilages covering opposing bones surfaces within synovial joins such as the elbow or knee

Elastic Cartilage

-numerous elastic fibers that make it extremely resilient and flexible

-forms external flap of ear, small cartilages of the larynx, and auditory tube in ear

-provides support but tolerates distortion without damage and returns to original shape

Fibrous Cartilage

-little ground substance

-matrix is dominated by collagen fibers

-lie in areas of high stress such as between spinal vertebrae, between pubic bones of the pelvis

-resist compression, absorb shocks, and prevents damaging bone-to-bone contact

osteocytes

bone cells

canaliculi

-passageways that extend through the matrix

-form a branching network for the exchange of materials between the blood vessels and osteocytes

2 Types of Bone

compact- which contains blood vessels trapped within the matrix

spongy- which doesn't

periosteum

-fibrous layer on outside and cellular layer on inside

-sheath surrounding bone surface

-assists in the attachment of a bone to surrounding tissues and to associated tendons and ligaments

-cellular layer- functions in bone growth and participates in repairs after injuries

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