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 TissuesI. 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

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

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

Liquid Connective Tissue

• Cover and protect other structures in the body

• Composed of epithelium and connective tissue

• Four types

– Mucous

– Serous

– Cutaneous

– Synovial

Membranes

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

Practice

Bone

Loose connective tissue - adipose tissue (fat)

More Practice

Hyaline cartilage

Liquid connective tissue - blood

More Practice

Dense irregular connective tissue – periosteum (outside of all bones)

Dense regular connective tissue - tendon

More Practice

Elastic connective tissue - between vertebrae

Simple columnar epithelium – lining of digestive tract