Part II Connective Tissue Most abundant and widely distributed tissue Main classes: 1.Connective tissue proper (loose & dense) 2.Cartilage 3.Bone 4.Blood Functions: 1.Binding and support 2.Protection 3.Insulation 4.Transport substances Variation in Blood supply Vascular connective tissue proper, blood, bone Tendons & ligaments are poorly vascular Cartilage is avascular Do not appear on surface Unlike epithelial Extracellular matrix secreted by cells that provides structural and biochemical support Ground substance: fills spaces, surrounds fibers, clear, colorless, and has the consistency of syrup water + adhesion proteins + polysaccharides Fibers provide support Collagen - no branching; strength Elastic branched; provides stretch Reticular fine branched network, skeleton of organs Collagen As you get older, your body makes less collagen, and individual collagen fibers become increasingly cross-linked with each other. stiff joints from less flexible tendons, or wrinkles due to loss of skin elasticity Plastic surgery? Put it through hydrolysis gelatin Known as the universal packing material Subclasses: areolar, adipose, reticular Structure: softer, fewer fibers, gel-like matrix Functions: Cushion & protect organs (areolar, fat) Store nutrients (fat) Internal framework of support (reticular) Fight infection (areolar) Cellular makeup: fibroblasts, adipocytes (fat cells) Locations: under skin, lymph nodes, hips, behind eyeballs Functions: Cushioning surrounding organs, connecting different tissues, and supporting blood vessels Made up of: collagenous, elastic and reticular fibers and ground substance Functions: store energy in the form of fat, although it also cushions and insulates the body. In mammals, two types of adipose tissue exist: white adipose tissue (WAT) brown adipose tissue (BAT). Adipose tissue is primarily located beneath the skin, but is also found around internal organs. Named for the reticular fibers which are the main structural part of the tissue. Cells that make the reticular fibers are fibroblasts called reticular cells. Function: fibers form a soft internal skeleton that supports other tissues Found: lymph organs, spleen, and bone marrow Poor circulation, build up of toxins, pressure on connective tissue Hormones to blame? 90% of women have it Why not seen in men as much? Women have less supportive connective tissue to keep fat cells in place. Tendons & ligaments Subclasses: dense regular, dense irregular, elastic Structure: mainly collagen fibers Functions: Elastic Resist tension Cells: fibroblasts Locations: tendons (muscle-bone), ligaments (bone-bone), lower layers of skin. RegularIrregular Parallel fibers Tears when stressed in the incorrect direction Found: tendons, ligaments Woven network of fibers Can be stressed in many directions Found: lower levels of skin 4/5 of all skin tissues are dense irregular Subclasses: hyaline, elastic, fibrocartilage Structure: flexible, no nerves or blood Functions: Support Compression Cells: chondrocytes Create and maintain the cartilaginous matrix Locations: larynx, joints, tip of nose, ear, intervertebral discs, rib-breastbone, knee joint. Resembles hyaline cartilage but it also has elastic fibers Provides flexibility and support Found in the outer ear, epiglottis, larynx Helps with joint movement, bone growth, strengthens respiratory tract Found in bronchi, joint surface, larynx Densely packed collagen fibers fibers that are in wavy lines Function: Support and protection Found: bone joints, knee, backbone Osseous tissue Subclasses: compact, spongy Structure: hard, calcified matrix; blood vessels Functions: support & protect Store calcium Blood cell formation (marrow) Cells: osteoblasts, osteocytes Synthesize bone Locations: bones Vascular tissue Subclasses: blood cells, plasma Structure: fluid within blood vessels, no fibers Functions: Transport vehicle (nutrients, wastes, gases, hormones) Cells: white blood cells (leukocytes), red blood cells (erythrocytes), platelets Locations: blood vessels