TISSUE

AGGREGATE OR GRROUPS OF CELLS ORGANIZED TO PERFORM

SPECIFIC FUNCTIONS

FOUR BASIC TISSUES

• EPITHELIUM COVERING & LINNING MEMBRANES• CONNECTIVE TISSUE SUPPORTIVE TISSUE• MUSCULAR TISSUE CONTRACTILE TISSUE• NERVOUS TISSUE EXCITABILITY

EPITHELIUM

• LAYER/LAYERS OF CLOSELY APPOSED CELLS WITH LITTLE INTER CELLULAR MATERIAL RESTING ON A BASEMENT MEMBRANE

CHARACTERISTICS

• POLARITY APICAL LATERAL & BASAL DOMAINS

• BASEMENT MEMBRANE• SPECIALIZED CELL JUNCTIONS• AVASCULARITY• INNERVATION• RENEWAL OF CELLS• METAPLASIA

CLASSIFICATION

• NUMBER OF CELL LAYERS

SIMPLE EPITHLIUM

STRATIFIED EPITHLIUM• MORPHOLOGY OF SURFACE CELLS

SQUAMOUS, CUBOIDAL

COLUMNAR

SIMPLE SQUAMOUSEPITHLIUM

• Thin flat scale like cells• Width > height• Central bulging nucleus surrounded by attenuated

cytoplasm (few organelles)• Specific names in specific locations endothelium, mesothlium• Transverse section mosaic like with irregular or straight

boundries • Functions passive exchange ( endothelium, lungs) reducing friction( mesothelium) barrier( junctions)

SIMPLE CUBOIDAL EPITHELIUM

• HEIGHT =WIDTH

• CENTRAL ROUND NUCLEUS

• EQUAL AMOUNT OF CYTOPLASM• LINNING OF PASSAGES

• ABSORPTIVE & SECRETORY FUNCTION

SIMPLE COLUMNAR EPITHELIUM

• HEIGHT > WIDTH

• OVAL BASAL NUCLEUS

• SECRETORY & ABSORPTIVE EPITHLIEM

• WITHOUT SURFACE SPECIALIZATION – ( STOMACH)

• SURFACE SPECIALIZATION

MICROVILLI, CILIA, GOBLET CELLS

SIMPLE COLUMNAR CILIATED EPITHLIUM

• COLUMNAR CELLS WITH CILIA ON THE APICAL SURFACE

• CAPABLE OF MOVING FLUID & PARTICLES ALONG EPITHELIAL SURFACE

• CREWCUT APPEARANCE short fine hair on the free surface & a dark

staining band extending across the cell at the base of cilia due to presence of basal body

BRONCHI OVIDUCT

CILIA Motile extension of cytoplasm covered by cell membrane Light microscopic Microtubules central pair & 9 doublet Central pair (central sheath, radial spokes) doublet (2 tubules) A complete, B incomplete 13+10 Dyenin ( motor protein) nexin ( passive elastic componet permanet) Basal body modified centriole Cilia develop from procentrioles Regular synchronous movement effective & recovery strokes Kartegnar syndrome

CENTRIOLES

• Paired short rod like cylinders• Nine triplet microtubules surrounding an

internal lumen• Perpendicular to each other`• Centrosome• Function Basal body formation, Mitotic spindle,

microtubule formation

COLUMNAR EPITHELIUM WITH MICROVILLI

• FINGER LIKE E/M PROJECTIONS OF THE CYTOPLASM COVERED BY CELL MEMBRANE

• Striated & Brush border

• Number variable

• L/M faint line

• Absorptive• Intestine ,Kidney

MICROVILLI

• E/M• ACTIN CORE • ANCHORED

APEX VILLIN

BASE TERMINAL WEB

SIDES FASCIN & FIMBRIN

TERMINAL WEB actin filament stabilized spectrin also contains myosin II & tropomyosin

STEROCILIA

• MISNOMER • LONG MICROVILLI• EPIDIDYMIS VAS DEFERENCE INNER EAR

• THICK STEM CONNECTED BY CYTOPLASMIC BRIDGES

• VILLIN ABSENT• ERZIN REPLACES MYOSIN I• ALPHA ACTININ

GOBLET CELL

• UNICELLULAR GLAND

• Mucous producing (viscous suspension of complex glycoproteins)

• Dilated upper part vacuolated

• stem like base( organelles)

• Intestinal & respiratory epithelium

SENSORY EPITHELIUM

• Neuro epithelial cells

• Epithelial in otigin with specialized sensory functions

• Taste bud , olfactory epithelium

MYOEPITHELIAL CELLS

• Epithelial in origin

• Contractile apparatus

• Between secretory cells and basement membrane