Chapter 4 (Connective Tissue)

Compact Bone & Spongy Bone

1. Extracellular Matrix: makes it able to withstand tension, abuse and weight better than other tissues

2. Common Origins: all connective tissue comes from mesenchyme

Ground Substance, Fibers, and Cells

unstructured material that fills the space between cells and surrounds fibers

molecular sieve that lets nutrients and substances diffuse

allows connective tissue cells to attach to extracellular matrix

consist of protein core to which glycosaminoglycans are attached

proteins that provide support ; 3 types: collagen, elastic, reticular

made by collagen ; extremely tough & provide strength to matrix

made from elastin ; allows stretch and recoil

Made of collagen 3 (coarser collagen) ; surround small blood vessels and support soft tissue of organs

1. Fibroblasts

2. Chondroblasts

3. Osteoblasts

4. Adipocytes

5. Leukocytes

6. Mast Cells

7. Macrophages

become fibrocytes in connective tissue proper

become chondrocytes in cartilage

become osteocytes in bones

actively dividing and secrete ground substance and fibers specific to their particular matrix

Maintain health of the matrix ; if matrix is injured they can easily revert to blast form and repair and regenerate

store energy as fat

concerned with tissue response to injury

detect foreign microorganisms and initiate local inflammatory responses using secretory granules w/ chemicals

3 chems they release: histamine, heparin, proteases

chemical that prevents blood clotting

makes capillaries leaky

protein degrading enzymes

devour foreign materials and dispose of dead cells

Fibers and Ground Substance

1. areolar connective tissue

2. adipose connective tissue

3. reticular connective tissue

most distributed connective tissue ; binds body parts while allowing them to move freely

Function: supporting & binding ; holding body fluids ; defense against infection

storing nutrients as fat in Adipocytes

stored nutrients much better than areolar tissue ; in subcutaneous tissue

Function: provide reserve food fuel ; insulate against heat loss ; support and protect organs

has reticular fibers inside a gel-like ground substance ; in lymph nodes

Function: form a soft internal skeleton that supports other cell types

1. dense regular connective tissue

2. dense irregular tissue

3. elastic connective tissue

closely packed collagen fibers running in the same direction ; found in tendons

Function: withstand tension in one direction

closely packed & thicker collagen fibers arranged irregularly ; located in dermis of skin

Function: withstand tension in many directions

very elastic due to big portion of elastic fibers ; located in walls of large arteries

Function: allow tissue to recoil after stretching

stands up to both tension & compression; lacks nerve fibers & is avascular; nourished via blood diffusion

predominant cell type in growing cartilage; produce new matrix

Found in lacunae ; maintain matrix

most abundant in body ; collagen fibers not visible w/ light microscope; found in coastal cartilage

Function: support and reinforce

has more elastic fibers; more visible under light; located in epiglottis

Function: maintain shape but still allow flexibility

thick collagen fibers; similar to hyaline; located in intervertebral discs

Function: absorb compressive shock w/ tensile strength

supports and protects body; also store fat and synthesize blood cells

produce organic portion of matrix

in lacunae; maintain matrix

atypical, fluid connective tissue ; doesnt connect or support ; derived from mesenchyme

Function: transport