Connective Tissue Overview

Overview

This lecture covers the types, components, and functions of connective tissue, emphasizing their structure, classification, and unique properties.

The four main types of connective tissue are connective tissue proper, cartilage, bone, and blood.
Connective tissue functions include binding, support, protection, insulation, storage, and transportation.
All connective tissues originate from embryonic mesenchyme.

Connective tissue is composed of cells and an extensive extracellular matrix.
The extracellular matrix consists of ground substance and fibers.
Ground substance includes interstitial fluid, cell adhesion proteins, and proteoglycans.
Fibers in connective tissue include collagen (strongest), elastic (stretchy), and reticular (supportive networks).

Immature cells end with "-blast" and create matrix; mature cells end with "-cyte."
Fibroblasts/fibrocytes form connective tissue proper; chondroblasts/chondrocytes form cartilage; osteoblasts/osteocytes form bone.
Adipocytes (fat cells) and other cells are also present.

Subdivided into loose (areolar, adipose, reticular) and dense (regular, irregular, elastic) connective tissue.
Areolar tissue is abundant, supportive, and stores fluid.
Adipose tissue stores fat and insulates.
Reticular tissue supports certain structures with a network of fibers.
Dense regular tissue forms tendons and ligaments, resisting tension in one direction.
Dense irregular tissue resists tension in multiple directions.
Dense elastic tissue is primarily elastic fibers for stretch.

Cartilage is tough, withstanding tension and compression, but lacks nerves and blood vessels.
Hyaline cartilage is abundant, firm, and cushions structures.
Elastic cartilage contains more elastic fibers and is flexible (e.g., ear).
Fibrocartilage has rows of chondrocytes and collagen, found in intervertebral discs.

Bone (osseous tissue) is hard due to collagen and inorganic calcium salts and contains blood vessels.
Blood is a connective tissue with cells in a fluid matrix (plasma), originating from mesenchyme.

Mesenchyme — embryonic tissue from which all connective tissues derive.
Extracellular matrix — non-cellular material (ground substance + fibers) surrounding connective tissue cells.
Collagen fibers — strong, rope-like fibers providing tensile strength.
Elastic fibers — stretchy fibers allowing tissue flexibility.
Reticular fibers — thin, network-forming fibers supporting soft tissues.
-blast — suffix indicating immature, matrix-producing cells (e.g., fibroblast).
-cyte — suffix for mature, less active cells (e.g., osteocyte).

Review and compare structural features of each connective tissue type.
Prepare for detailed study of blood, muscle tissue, and nervous tissue in future lessons.