Part II: Connective Tissue 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 Classification . Variations in blood supply Avascular (no blood) – cartilage Poorly vascular – tendons, ligaments . Extracellular matrix Produced by cells, secreted to exterior Ground substance: “glue” - fills space between cells & fibers water + adhesion proteins + polysaccharides Fibers: provide support Collagen - 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: fibroblasts, adipocytes (fat cells) . Locations: under skin, 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 nerves or blood . Functions: Support Compression . Cells: chondroblasts, chondrocytes . Locations: larynx, joints, tip of nose, ear, 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: bones
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