Connective Tissue

COnnective TissueConnective Characteristics

· bind, support, protect, fill spaces, store fat, produce blood cells· widely distributed throughout body· most have a good blood supply· cells are farther apart than in epithelium· plenty of extracellular matrix

fibers and a ground substances (solid to semisolid)

Major Cell Types· fixed cells

fibroblasts (fiber builders) - most common; large, star shaped; produce fibers

mast cells - large; located near blood vessel; release heparin (prevents blood clotting) and histamine (inflammation and allergies)· wandering cells

macrophages (large eater) - carry on phagocytosis

Connective Tissue Fibers· fibroblasts produce 3 typed of fibers

collagenous, elastic, and reticularcollagenous and elastic most abundant

· collagenous fibers - great tensile strength (resist pulling force)

tendons (muscle to bone) and ligaments (bone to bone) found in dense connective tissues

a.k.a. white fibers because they appear white when grouped together· elastic fibers - stretch easily

thin fibers that branchnot as strong as collagenous, but return to original shape

after stretching a.k.a. yellow fibers· reticular fibers - delicate support

thin collagenous fibershighly branched

2 Types of Connective Tissue· connective tissue proper

loose connective tissue, adipose tissue, and dense connective tissue· specialized connective tissue

cartilage, bone, blood

Connective Tissue

Loose Connectie Tissue· a.k.a. areolar tissue· bind organs together and holds tissue fluid· main cell type - fibroblast· extracellular matrix - gel-like with many collagenous and elastic fibers· beneath skin, between muscles, beneath epithelial tissues

Adipose Tissue· a.k.a. fat· protects, insulates, and stores fat· specialized loose connective tissue

adipocytes (fat cells) store fat droplets with their cytoplasm and enlarge· beneath skin, around kidneys, behind eyeballs, surface of the heart

Dense COnnective Tissue· binds organs together· cells - few fibroblasts· extracellular matrix - closely packed, thick collagenous fibers and a network of elastic fibers· poor blood supply (heals slowly)· tendons, ligaments, deeper layer of skin

Cartilage· cells - chondrocytes· extracellular matrix - abundant, gel-like with collagenous fibers· chondrocytes group together in lacunae· perichondrium (around the cartilage) surrounds cartilaginous structures

blood supply to cartilage· torn cartilage heals slowly

Cartilage - 3 Types· 3 types based on extracellular matrix

hyaline, elastic, fibrocartilage· hyaline

fine collagenous fiberssupports, protects, provides frameworknose, ends of bones, rings in the walls of respiratory passages

· elasticdense elastic fiberssupport, protects, provides flexible frameworkpinna (external ear) and parts of larynx (voice box)

· fibrocartilagetough tissue, many collagenous fiberssupport, protects, absorbs shockbetween vertebra, knee, pelvic girdle

Bone· cells - osteocytes (bone cells)· extracellular matrix - rigid, full of collagenous fibers, mineral salts provide hardness· matrix forms concentric circles· good blood supply (heals quickly)· supports, protects, provides framework, produces blood cells· bones of skeleton

Connective Tissue

Blood· blood - formed elements + plasma

cells (formed elements) - WBC, RBC, plateletsmatrix - plasma (watery)

· transports substances, helps maintain homeostasis· throughout body with a closed system of blood vessels and heart chambers