Tissue Level Friday September 28 2012 12 25 PM Tissue A group of similar cells that perform a common function 4 Types EPITHELIAL TISSUE covering Exhibit polarity Lower attached basal surface Upper free apical surface may have cilia microvilli Avascular lack blood vessels Supported by basement membrane double layered superior basal lamina Connective tissue underlies epithelial High regenerative capacity undergo cell division Innervated Membranous Epithelia covering and lining Simple epithelia Single layer squamous cuboidal columnar Stratified epithelia Several layers squamous cuboidal columnar Simple squamous epithelium single layer flattened cells nuclei diffusion filtration Kidney lungs air sacs lining of heart blood vessels and lymphatic vessels a Endothelium lines structures in circulatory system cardiovascular lymphatic b Mesothelium Simple cuboidal epithelium single layer cubelike cells secretion absorption Kidney tubules ducts and secretory glands a Germinal epithelial tissue that surrounds ovary surface Simple columnar epithelial single layer may have cilia may have mucous secreting glands goblet cells secrete mucin thick sticky substance traps debris pathogens absorption secretion of mucous digestive tract stomach to anal canal gallbladder excretory ducts of glands bronchi uterus a Non ciliated tissue in digestive tract microvilli b Ciliated tissue in respiratory tract bronchi unidirectional carrying mucus away from lungs Pseudostratified Pseudo false columnar epithelial single layer not stratified nuclei at different levels secretion mucus propels mucus male sperm carrying ducts trachea a Non ciliated lines male sperm carrying ducts b Ciliated respiratory tract Stratified squamous epithelium several layers basal cuboidal columnar surface flattened squamous metabolically active surface keratin dead a Non keratinized lines esophagus mouth and vagina protection secretion b Keratinized forms of epidermis of skin keratin is a tough fibrous protein abrasive resistant Stratified columnar epithelium 2 layers of cells apical columnar shape secretion protection ducts of glands pharynx and male urethra Stratified cuboidal epithelium 2 layers apical cuboidal shape secretion protection salivary sweat glands ducts Transitional epithelium basal cells columnar cuboidal dome shaped surface stretches readily to permit distension for urine lines ureters bladder and urethra Glandular Epithelia forms glands that secrete Endocrine Glands secrete products hormones into extracellular fluid not equipped with ducts Exocrine Glands secrete product onto body s surface have ducts b Multicellular Glands equipped with ducts Compound Glands Straight Branched ducts i Simple Glands Unbranched ducts ii Shape tubular alveolar tubular alveolar Step 1 simple or compound Step 2 shape formed by epithelial cells a Unicellular Glands not equipped with ducts ex Goblet cells only ones dispersed in pseudostratified columnar epithelial simple columnar epithelial CONNECTIVE TISSUE support Dense Connective Tissue fibrous increase of fiber in the extracellular matrix bundles of collagen fibers arranged in orderly fashion all face in same direction Location tendons attaches skeletal muscle to bones Aponeurosis are sheet like tendons that attach muscle to muscle Ligaments are cord like structures that unite bones at a joint Dense regular CT poorly vascularized this is why healing of a ligament tendon takes a long time substances for repair delivered via blood stream Function attachment provides tensile strength to the structures it s attaching can withstand stress force applied parallel to the collagen fibers Dense Irregular CT bundles of collagen fibers arranged in an irregular fashion face all different directions highly vascularized Location reticular layer of the dermis Function forms fibrous capsules that surround and protect structures provides nutrients to the structures that support and protect b c of vascularity Elastic CT similar to dense regular CT with the presence of bundles of elastic fibers Function exhibits stretch recoil properties provides tensile strength Location ligamenta flava between adjacent vertebrae allows for the bending of the vertebral column stretches and recoils to the normal anatomical shape of the vertebral column Cartilage 2nd class of CT produced secreted by condroblasts semi solid ground substance shallow concavities called lacunae matured chondroblasts called chondrocytes reside in the lacunae Hyaline most abundant type of cartilage matured cartilage is avascular receives nutrients from the perichondrium which surrounds the cartilage Perichondrium is composed of dense irregular CT Function supports and reinforces resilient cushioning properties resists stress Location forms most of embryonic skeleton during development the embryonic skeleton is ossified into bones ends of long bones persists as the epiphyseal plates between the epiphysis and diaphysis of long bone ribs nose trachea and larynx Persists as the costal cartilages to attach the ribs to the sternum Elastic more elastic fibers in matrix than hyaline Function stretch recoil properties allows pinna to direct sound waves into the external auditory canal stretch in the epiglottis to close off the glottis into the larynx in the lower respiratory tract prevents swallowed substances in pharynx from getting into the lower respiratory tract maintains shape of structure while allowing flexibility Location ear pinna and epiglottis Fibrocartilage less firm than hyaline blend between dense regular CT and hyaline cartilage bundles of collagen fibers alternating with rows of lacunae with chondrocytes residing in them Resilient but flexible and acts as shock absorbers minimize wear and tear Location Intervertebral discs and knee joint Function Tensile strength absorb shock Pubic symphyses joins to 2 oxcoxae allows passage of fetal head during labor Bone Osseous Tissue secreted by osteoblasts directly derived from mesenchyme non living portion is extracellular matrix organic inorganic matrix Hydroxy Apatites calcium phosphate crystols impregnating the osteoid solid matrix has lacunae matured osteoblasts called osteocytes reside in lacunae Blood fluid matrix called Blood Plasma contains protein called Fibrinogen when blood clots it goes from soluble to insoluble NERVOUS TISSUE Nervous neurons nerve cells generate transmit action potentials conducting cells neuroglia supporting cells 3 parts cell body nucleus Amitotic lacks a centrosome
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