CONNECTIVE TISSUE Connects body parts

Most abundant tissue type Most abundant tissue type Widely spread Widely spread Made up of many types of cells Made up of many types of cells

Common Characteristics 1. Blood supply: –Most well vascularized –Some have poor blood supply: *Tendons and ligaments – poor *Cartilages – avascular * Heal slowly

2. Extracellular Matrix- n onliving substance found outside cells - produced by connective tissue - secreted to exterior

Two Main Elements of the Matrix 1. Ground Substance: –Water –Adhesion proteins – glue fibers to cells –Large, charged polysaccharides (trap water as they intertwine)  Less: fluid  More: rock-hard

2. FIBERS Collagen (white) Collagen (white) Elastic (yellow) Elastic (yellow) Reticular (fine collagen) Reticular (fine collagen)

SCURVY Loss of collagen Loss of collagen Deficiency of Vitamin C (necessary in formation of collagen fibers) Deficiency of Vitamin C (necessary in formation of collagen fibers) Skin sores, spongy gums, weak blood vessels, poor healing of wounds Skin sores, spongy gums, weak blood vessels, poor healing of wounds

Matrix Soft packing tissue around organs Soft packing tissue around organs Bears weight Bears weight Absorb large amount of water Absorb large amount of water Withstand stretching, abrasion, etc Withstand stretching, abrasion, etc Ex: Fat: mostly cells  soft Ex: Fat: mostly cells  soft Bone/Cartilage: few cells, more Bone/Cartilage: few cells, more matrix  extremely strong matrix  extremely strong

TYPES OF CONNECTIVE TISSUE Fiber type Fiber type Number of fibers in matrix Number of fibers in matrix

BONE Osseous tissue Osseous tissue Bone cells sitting in lacunae (cavities) Bone cells sitting in lacunae (cavities) Surrounded by layers of hard matrix with Ca salts and collagen fibers Surrounded by layers of hard matrix with Ca salts and collagen fibers Protect and support body organs Protect and support body organs

CARTILAGE Less hard, more flexible Less hard, more flexible 1. Elastic: elasticity (ear) 2. Fibrocartilage: highly compressable (disks between vertebrae)

3. Hyaline: most widespread Collagen fibers hidden by rubbery matrix with glassy, blue-white appearance Collagen fibers hidden by rubbery matrix with glassy, blue-white appearance Larynx, ribs, covers ends of bones at joints Larynx, ribs, covers ends of bones at joints Skeleton of fetus Skeleton of fetus

Dense Connective Tissue AKA: Dense Fibrous Tissue AKA: Dense Fibrous Tissue Collagen fibers with fibroblasts in between Collagen fibers with fibroblasts in between Stong, ropelike Stong, ropelike –TENDONS: attach skeletal muscles to bone –LIGAMENTS: connect bones to bones at joints

Medial Collateral Ligament

LOOSE CONNECTIVE TISSUE Softer Softer More cells, fewer fibers More cells, fewer fibers 3 types 3 types

AREOLAR TISSUE Soft, pliable Soft, pliable Cushions, protects, holds together organs Cushions, protects, holds together organs Lamina propria: soft layer underlying all mucous membranes Lamina propria: soft layer underlying all mucous membranes Most of matrix appears to be empty space because of loose and fluid nature Most of matrix appears to be empty space because of loose and fluid nature Reservoir of salts and water Reservoir of salts and water

Edema When a body region is inflamed, the areolar tissue soaks up excess fluid When a body region is inflamed, the areolar tissue soaks up excess fluid The area becomes puffy The area becomes puffy Phagocytes scavenge through this tissue Phagocytes scavenge through this tissue

ADIPOSE TISSUE Areolar tissue: fat cells predominate Areolar tissue: fat cells predominate Signet ring cells: bulging nucleus looks like a ring Signet ring cells: bulging nucleus looks like a ring Forms subcutaneous tissue beneath skin Forms subcutaneous tissue beneath skin Insulates: temp., organs Insulates: temp., organs fuel fuel

Reticular Connective Tissue Delicate network of interwoven reticular fibers Delicate network of interwoven reticular fibers Forms STROMA (bed): internal supporting framework Forms STROMA (bed): internal supporting framework Supports free blood cells in lymphoid organs (lymph nodes, spleen, bone marrow) Supports free blood cells in lymphoid organs (lymph nodes, spleen, bone marrow)

BLOOD Blood cells surrounded by blood plasma (nonliving, fluid matrix) Blood cells surrounded by blood plasma (nonliving, fluid matrix) ‘Fibers’ of blood become visible during clotting ‘Fibers’ of blood become visible during clotting Carries nutrients, wastes, gases Carries nutrients, wastes, gases