Connective Tissue Four Basic Kinds of Tissues Epithelial

Connective Tissue

Four Basic Kinds of Tissues • • Epithelial Tissue Connective Tissue Muscle Tissue Nervous Tissue

Connective Tissue Extracellular matrix Fibroblasts Collagen Fibers Reticular Fibers Elastic Fibers

Connective Tissue • • Most abundant & widely distributed tissue throughout the body (bones, blood, fat, etc. ) No contact with the outside Composition: 1. Specialized cells (chondrocytes, macrophages, melanocytes, adipocytes, lymphocytes, etc. ) 2. Extracellular protein fibers (collagen, reticular, or elastic) 3. Ground substance (often fluid) Matrix

Functions of Connective Tissue Functions: • Establishing a structural framework • Transporting fluids and dissolved materials • Protecting delicate organs • Supporting, surrounding and interconnecting tissues • Storing energy reserves • Defending the body from microorganisms

Classification of Connective Tissues I. Loose Connective Tissue (support, cushioning) 1. Areolar - cushions organs 2. Reticular - live, spleen 3. Adipose - fat II. Dense Connective Tissue (fibrous) 1. Dense regular - tendons 2. Dense irregular - white, protective layer of eye 3. Elastic – bronchial tubes, large arteries III. Cartilage (flexible, strong support) IV. Bone (structure, support) V. Liquid Connective Tissue (fluid) 1. Blood (erythrocytes – red blood cells, platelets) 2. Lymph (leukocytes – white blood cells)

Loose & Dense Connective Tissue • Contains varied cells and fiber types; syrupy ground substance Cartilage & Bone • Dense ground substance & closely packed fibers Liquid Connective Tissue • Watery ground substance with dissolved proteins

Loose Connective Tissue

Dense Connective Tissue Fig. 4. 10

Dense Connective Tissue

Cartilage Most abundant, tough but flexible

Cartilage Elastic fibers make cartilage flexible and resilient

Cartilage Dense collagen fibers make fibrocartilage tough and durable

Bone has very little substance, strength is due to calcium salts & collagen fibers

Liquid Connective Tissue

Membranes • Cover and protect other structures in the body • Composed of epithelium and connective tissue • Four types – Mucous – Serous – Cutaneous – Synovial

Membranes • Fig. 4. 15 • Mucous membranes: Line cavities that are in contact with the exterior; kept moist • Serous membranes: Line sealed internal cavities • Cutaneous membranes: Cover the body surface (skin) • Synovial membranes: Lining within joint cavities