Tissue LevelFriday, September 28, 201212:25 PMTissue - 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 ductsb. 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/secretionb. 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 ductsa. Unicellular Glands - not equipped with ducts (ex. Goblet cells - only ones, dispersed in pseudostratified columnar epithelial & simple columnar epithelial)b. Multicellular Glands - equipped with ductsi. Compound Glands - Straight/Branched ductsii. Simple Glands - Unbranched ductsShape: tubular, alveolar, tubular alveolarStep 1: simple or compoundStep 2: shape formed by epithelial cells…. 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 bonesAponeurosis are sheet-like tendons that attach muscle to muscleLigaments 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 dermisFunction: 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 fibersFunction: exhibits stretch-recoil properties, provides tensile strengthLocation: 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 CTFunction: supports and reinforces, resilient cushioning properties, resists stressLocation: 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 flexibilityLocation: 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 tearLocation: Intervertebral discs and knee jointFunction: 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
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