Connective Tissue

Characteristics of Connective Tissue

-does not occur on free surfaces

-some are vascularized, not all (tendons and ligaments poor, cartilage none)

Connective Tissue Functions

Binding and support protection, insulations, transportation, cushion

Structural Elements of CT

Cell type, extracellular matrix, fibers

Cell types found in CT

Fibrocyte, chondrocyte, oseocyte, red blood cells

Fibers in CT

Collagen

Elastic

Reticular

cells secreted by connective tissue

Extracellular Matrix

nonliving substance surrounding cells
ECM is substance produced by cells and secreted to exterior

can bear weight, withstand tension, endure physical trauma that no other tissue can

Parts of ECM

Ground substance: made if water, adhesion proteins that help attach CT cells to matrix fibers, and polysaccharides that trap water, determining viscosity

GAGs trap water and determine viscosity, it attches to protein core

Collagen

interwoven thick network of collagen

extremely tough, high tensile strength

structural protein

Elastic Cartilage

can snap back when stretched

external ear, skin, lungs, blood vessel walls

structural protein

Reticular Fibers

-made of collagen fibers, extensive network

surround small blood vessels

abundant in areas where CT is next to another dif type of tissue (epithelium)

support small tissues and organs

structural protein

Different connective tissue

Osteocytes (bone), Chondrocytes-cartilage, loose connective tissue, dense connective tissue, blood

Bone

made of osteocytes

matrix is made of abundant collagen fibers and inorganic calcium salts

osteocytes sit in lacunae (small cavity) surrounded by lamellae [(compact bone tissue) (round circles seen on tissue)] made of calcium salts and collagen

Cartilage

secreted by chondrocytes and more flexible than bone

tough but flexible

no nerve endings or blood vessels

nourished by neighboring connective tissue

matrix: GAGs (gel like substance, long unbranched polysaccharide attached to protein) specifically GAG chondroitin sulfate and hyaluronic acid and collagen fibers)

80% water

chondrocytes sit in lacunae

Different types of cartilage

Fibrocartilage

Hyaline

Elastic cartilage

Fibrocartilage

intervertebral discs that help reduce impact on bounds and relieve shock

spongy cartilages in the knee

Hyaline Cartilage

abundant collagen, rubbery matrix

forms fetal skeleton, trachea, covers epiphyses(growth plates)

on joints to reduce friction

Elastic Cartilage

has more elastic fibers

can snap back when stretched

makes up the external ear

types of dense connective tissues and def

dense regular and dense irregular

collgen fibers dominate

scant ground substance, cells, and blood supply

Dense Regular Connective tissue

made up widely of collagen fibers

surrounded by fibroblasts to manufacture fibers a little bits of ground substance

strong ropy structures

forms tendons that connect muscle to muscles to bone

forms ligaments that attach bones to bones/ joints (have more elastic fibers)

tension in one direction

Dense Irregular Connective Tissue

same structural elements of dense connective

difference is in thickness of collagen fibers and the random arrangement

makes up lower layers of skin

Loose connective tissue

most widespread CT in the body

abundant ground substance, scant collagen fibers, and many cells

Types of Loose Connective Tissue

areolar, adipose, reticular, blood

Areolar CT

most widely distributed CT

cobwebby-loose arrangement of fibers

cushions and protects organs

helps hold organs in positions

defense against infection

acts as a reservoir for salts and water for surrounding body tissues, soaks up extra during inflammation

lamina propria (thin layer of connective tissue) underlies all mucous membranes

Adipose Tissue

areolar tissue dominated by adipose (fat cells)

oil occupies most of cytoplasm

insulates and protects body and organs

also used for energy, as fat deposits are energy banks

highly vascularized

Reticular Tissue

forms a internal framework that can support free blood cells

made by woven reticular fibers

stroma= internal framework for organs

lymph nodes, spleen

Blood

vascular tissue

blood cells surrounded by nonliving plasma; fibers only visible during clotting

transport system around the body