Specialized Connective Tissue

Special Connective Tissues

cartilage, hyaline cartilage, fibrocartilage, elastic cartilage

Cartilage

Tough, flexible tissue that absorbs shock and is resistant to tension, compression, and shearing forces

ECM is solid and gel-like with glycosaminoglycans, proteoglycans, collagen fibers, and elastic fiber

includes chondroblasts and chondrocytes, surrounded by perichondrium

Chondroblasts

immature cartilage cells

Chondrocytes

Mature cartilage cells, which live in small cavities called Lacunae

Perichondrium

cartilage is surrounded by an outer sheath of dense irregular connective tissue called the perichondrium

supplies blood to the cartilage

Hyaline Cartilage

ECM is ground substance with a fine type of collagen that forms small bundles

Covers ends of bones, rib attachment sites to the sternum, and the nose and the respiratory tract

Makes most of the fetal skeleton

Fibrocartilage

ECM is filled with bundles of collagen and some elastic fibers made by fibroblasts

Found in fibrous joints including the intervertebral discs and articular discs that improve the fit of 2 bones

Lacks a perichondrium

Elastic Cartilage

ECM is filled with elastic fibers

Found in external ear and parts of the framework of the larynx

Tissue can vibrate and assist in detection of sound in the air and production of sound by the larynx

Osteoarthritis

caused by age, joint trauma, genetic disorders, and infection

Develops as hyaline cartilage degenerates and proteoglycans and collagen fibers are destroyed

supposedly treated by glucosamine

Glucosamine

A popular dietary supplement that claims to treat osteoarthritis

derived from the chondroblasts of shellfish and some fungi

Hypothetically, supplementation with glucosamine could increase the production of chondroblasts and slow cartilage degeneration; however, studies have yielded mixed results

Further studies are needed to determine if glucosamine supplements can truly stall degeneration of joints in osteoarthritis

Bone

Supports the body, protects vital organs, provides attachment sites for muscles, stores calcium salts, and houses bone marrow, which produces our red blood cells and stores fat

has bone ECM and bone cells

Bone ECM

Organic Portion = 35% of bone mass

Made of collagen fibers and osteiod ground substance

Inorganic Portion = 65% of bone mass

Made primarily of calcium phosphate crystals

Bone Cells

osteoblasts, osteocytes, osteoclasts

Osteoblasts

Carry out bone deposition

Synthesize organic portion of ECM and produce chemicals required for calcium salts to deposit in ECM

Osteocytes

Mature osteoblasts that are surrounded by ECM

Live in lacunae

Produce substances for bone maintenance

Osteoclasts

Multinucleated cells that carry out bone resorption (break down)

Secrete hydrogen ions and enzymes to break down the ECM

Bone Remodeling

Bone deposition and bone resorption are constantly occurring in healthy bone

Tension on the bone results in increased osteoblast activity and bone deposition

Pressure on the bone results in increased osteoclast activity and bone resorption

By these processes, exercise can increase bone density

Blood

ECM is fluid and is called Plasma, with water, dissolved solutes, and globular proteins

Cells are Erythrocytes (red blood cells), which carry oxygen,

Leukocytes (white blood cells), which function in immunity,

and cell fragments called Platelets, which function in blood clotting