Connective Tissue

1. Bone: hard, calcified matrix containing many collagen fivers with blood vessels; supports & protects, provides levers for muscles, stores calcium & other minerals

1.1. Compact

1.2. Spongy

2. Blood: red & white blood cells in a fluid matrix; transport respiratory gases/nutrients/ wastes; found in blood vessels

3. Proper

3.1. Loose connective

3.1.1. Areolar: gel-like matrix with all 3 fiber types; wraps and cushions organs, macrophages eat bacteria, holds fluid, plays a role in inflammation; found under epithelia (mucous membranes, packages organs, surrounds capillaries)

3.1.2. Adipose: tighter matrix of closely-packed fat cells; provides reserve fuel, insulates against heat loss, protects organs; found around kidneys, eyeballs, abdomen, breasts

3.1.3. Reticular: network of reticular fibers in a typical loose ground substance; fibers form a soft internal skeleton that supports other cell types; found in lymph nodes, bone marrow, spleen

3.2. Dense connective

3.2.1. Regular: parallels collagen fibers with a few elastic fibers; attaches muscles to bones or other muscles, great tensile strength; found in tendons and most ligaments

3.2.2. Irregular: irregularly arranged collagen fibers with some elastic fibers; provides structural strength and withstands tension in many directions; found in fibrous capsules of organs and joints, dermis of the skin, submucosa of digestive tract

3.2.3. Elastic: dense tissue containing a high proportion of elastic fibers; allows tissue to recoil after stretching, allows blood to pulse through arteries, recoil of lungs; found in walls of large arteries, walls of bronchial tubes

4. Cartilage

4.1. Hyaline: shapeless but firm matrix made of a network of collage fibers containing chondrocytes; supports and reinforces, serves as a cushion, resists compressive stress; found in embryonic skeleton, costal cartilages of the ribs, nose, trachea, larynx

4.2. Elastic: structure similar to Hyaline, but with more elastic fibers; maintains the shape of a structure while allowing flexibility; found in external ear, epiglottis

4.3. Fibrocartilage: less firm than Hyaline with thick collagen fibers; tensile strength allows for absorption of compressive shock; found in intervertebral discs, discs of knee joint