connective tissue(most abundant tissue in body by weight)
areolar(aka loose connective tissue)
-"loose connective tissue" -mainly fibroblasts -elastic and collagenous fibers -binds skin to underlying organs -fills spaces between muscles
function of connective tissue
-binds structures together -protects against infection -provides support, protection and framework -fills spaces and stores fat -helps repair damaged tissue
adipose
-cells are adipocytes(store fat in droplets in cells) - cushions joints and some organs, insulates -found beneath the skin, around the kidney/heart, behind the eyes
bone
-composed of cells(osteocytes) in a hard calcified matrix -most rigid connective tissue -osteocytes deposit the bone matrix in layers, lamellae -supports, protects, provides a framework for muscle attachment -stores inorganic salts osteocytes, located in the lacuna, possess cytoplasmic process that pass through canals known as canaliculi -its found in the skeleton and middle ear
elastic connective tissue
-elastic fibers & fibroblasts in a solid gel matrix -connects vertebrae and is found in the walls of arteries and airways -supports, protects, and provides a flexible framework
cell types
-fibroblasts -mast cells -macrophages
elastic cartilage
-it's matrix contains many elastic fibers -found in the outer ear and part of the larynx -supports, protects and provides a flexible framework
elastic fibers
-made of bundles of elastin -air passages/ vocal cords -helps skin return to its original position when poked or pinched
collagenous fibers
-made of thick threads of collagen -they are strong flexible and inelastic -tendons and ligaments
hyaline cartilage
-most common -found in the ends of bones, nose and rings in the respiratory passages - supports, protects and provides a framework -looks like white glass
fibroblasts
-produce fibers by secreting proteins into matrix -most common "fixed" cell -large, star shaped
dense connective tissue
-thick collagenous fibers, thin elastic fibers & fibroblasts in a fluid-gel matrix -found in tendons, ligaments(regular) & the dermis of the skin(irregular) -binds organs together -poor blood supply
fibrocaritilage
-toughest -found between the vertebrae(intervertebral discs), in the knee and parts of the pelvic girdle -supports, protects and absorbs shock during movement
fiber types
collagenous fibers elastic fibers reticular fibers
blood
erythrocytes-RBC leukocytes-WBC -its found in blood vessels -composed of cells and platelets in a fluid matrix, the blood plasma - transports gases, nutrients and wastes, defends against disease and acts in clotting
3 types of cartilage
hyaline elastic fibrocartilage
macrophages
originate as WBC, they can move and phagocytize foreign particles
mast cells
release heparin-prevents blood clotting release histamine-which aids in inflammatory response
reticular fibers
thin collagenous fibers form branched networks for support