Part II: Connective . Most abundant and widely distributed tissue . Main classes: 1. Connective tissue proper (loose & dense) 2. 3. 4. Blood . Functions: 1. Binding and support 2. Protection 3. Insulation 4. Transport substances Classification . Variations in blood supply  Avascular (no blood) – cartilage  Poorly vascular – , .  Produced by cells, secreted to exterior  : “glue” - fills space between cells & fibers  water + adhesion + polysaccharides  Fibers: provide support  - strength  Elastic – stretch  Reticular – fine network, “skeleton” of organs

Loose Connective Tissue . 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 (reticular)  Fight infection (areolar) . Cells: , (fat cells) . Locations: under , lymph nodes, hips, behind eyeballs

Dense Connective Tissue

. 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

Cartilage

. Subclasses: hyaline, elastic, fibrocartilage . Structure: flexible, no or blood . Functions:  Support  Compression . Cells: , chondrocytes . Locations: larynx, joints, tip of nose, , intervertebral discs, rib-breastbone, knee joint

Bone

. Osseous tissue . Subclasses: compact, spongy . Structure: hard, calcified matrix; blood vessels . Functions:  support & protect  Store calcium  Blood cell formation (marrow) . Cells: osteoblasts, osteocytes . Locations:

Blood

. 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