Connective Tissue Overview

Study Notes

Connective tissues connect, support, and bind other tissues in the body
Originates from mesoderm
Key functions include providing structural support, facilitating metabolic exchange, being a site for fat storage, and aiding in defense and protection.

Cells: A variety of cell types exist, including fibroblasts, macrophages, mast cells, and more
Fibers: Collagen, elastin, and reticular fibers form the framework of the tissue
Matrix (ground substance): A surrounding material that varies in consistency from semi-solid to solid or liquid, depending on the specific type of connective tissue.

Connective Tissue Proper: Gelatinous or semi-solid ground substance (e.g., loose and dense connective tissues)
Fluid Connective Tissue: Fluid or liquid ground substance (e.g., blood and lymph)
Supporting Connective Tissue: Solid or rubbery ground substance (e.g., cartilage and bone)

Description: Gel-like matrix with all three fiber types (collagen, elastic, reticular); cells include fibroblasts, macrophages, mast cells, and white blood cells
Function: Wraps and cushions organs, phagocytizes bacteria, plays role in inflammation, holds and conveys tissue fluid
Location: Widely distributed beneath epithelia, forms lamina propria of mucous membranes, packages organs, surrounds capillaries

Description: Sparse matrix, closely packed adipocytes (fat cells) with large fat droplets displacing nucleus
Functions: Reserve food fuel, insulation, support and protection of organs
Location: Subcutaneous tissue, around kidneys and eyeballs, within abdomen, breasts

Description: Network of reticular fibers in a loose ground substance with reticular cells
Function: Forms a soft internal skeleton (stroma) supporting various cell types (e.g., white blood cells, mast cells, macrophages)
Location: Lymphoid organs (lymph nodes, bone marrow, spleen)

Dense Regular:
Description: Primarily parallel collagen fibers; a few elastic fibers
Function: Attaches muscles to bones or muscles; withstands great tensile stress when pulling force is applied in one direction
Location: Tendons, most ligaments, aponeuroses
Dense Irregular:
Description: Primarily irregularly arranged collagen fibers; some elastic fibers
Function: Withstands tension exerted in many directions, provides structural strength
Location: Fibrous capsules of organs and of joints, dermis of the skin, submucosa of digestive tract
Elastic:
Description: Dense regular connective tissue containing a high proportion of elastic fibers
Function: Allows tissue to recoil after stretching, maintains pulsatile flow of blood through arteries, aids passive recoil of lungs
Location: Walls of large arteries, within certain ligaments, walls of bronchial tubes