بسم الله الرحمن الرحيم
Cell tissue Tissue organ Organ system
Tissue 4 type: - epithelial tissue -connective tissue -muscular tissue -nervous tissue
Epithelial tissue Function: -covering & lining = skin and body cavity (intestine) - absorption = intestine - secretion = gland - sensation = neuro- epithelium -contractility = myo- epithelial cells
structure -specialized cells & extra cellular matrix -supporting : -Basal lamina -Connective Tissue
Basal lamina Basal lamina: extracellular structure Lamina lucida: proteoglycan (heparan sulphate) Lumina densa: collagen IV
Basement membrane Basal lamina + reticular layer
Polarity Three pole: Apical pole (free) basal pole Lateral pole
intercellular junction 1-chemical : glycoprotein inter cellular protein cadherins, Ca++ 2- mechanical : A- zonulae occludens B- zonula adherens D- macula adherns C- Gap junction
zonulae occludens =Tight junction
zonula adherens 1- actin micro filament 2- dense plaquc
macula adherens D- macula adherens = desmosome Distance = 20nm ( > 30nm) 1-Plaque (proteins) 2-Intermediate filament = cytokeratin
Hemi desmosome
Gap junction - Distance = 2nm -unite: connexon =6 protein (hexamere) hydrophilic canal (diameter = 1.5nm) Function: interchange
Specializations of the cell surface -Microvilli -Stereocilia -Cilia -Flagella
Microvillus location: apex core: actin microfilament covered: glycocalyx (glycoprotein )
stereocilia =long branched microvillus shape :cilia (non-motile process)
cilia =elonged & motile surround: by cell membrane core: microtubules 1- two central pair 2- nine peripheral pair =axonema pattern
Function of cilia Source of energy : ATP
Flagella Structure: similare of cilia Location: only in spermatozoa
Shape of epithelial cells Shape: polyhedral cell Form: columnar, cuboidal, squamous
Type of epithelia 1- covering epithelium 2- glandular epithelium
Covering epithelium Types: 1-simple 2-stratified
simple epithelium a- squamous epithelium b- cuboidal epithelium c- columnar epithelium
stratified epithelium a- st. squamous epithelium b- st. columnar epithleoum C-st. cuboidal epithleoum Type of stratified epithelium
stratified squamous epithelium -First layer (basal cell): cuboidal or columnar -surface layer: suamouse shape
Two type of epithelium: 1- keratinized: skin 2- non-keratinized: (esophagous, vagina)
stratified columnar epithleoum First (basal) layer: cuboidal Other layer: columnar
Other type of stratified epithelium d- transitional epithelium f- pseudostratified epithelium
transitional epithelium First(basal )layer: cuboidal Surrface layers: dome-like Location: urinary bladder (urinary sys.)
psudostratified epithelium layer: one( all cells attach to basal lamina) -Location :respiratory system
Specialized epithelium - neuro-epithelial cell – myo-epithelial cell
neuroepithelial cell origin: epithelial cell function: specialized sensory
myoepithelial cell shape: branched cell Contain: myosin &large number of actins filament function: specialized contraction
glandular epithelium structure: cells specialized secretory granule secretion fluid Composition: protein, lipid, complex of carbohydrate & protein
Type of glandular epithelium Endocrine gland: Exocrine gland:
exocrine gland Structure: 2 portion A- secretary portion: secretion of material B-ductal portion: transport secretion to exterior
type of glandular epithelium - unicellular gland: Isolated glandular cell -multi cellular gland: cluster of cells
unicellular gland Isolated glandular cell Example: goblet cell Location: small intestin, respiratory tract
multi cellular gland =cluster of cells proliferation & invasion into connective tissue
Types of multi cellular gland Two type of exocrine gland: Based on unbranched &branched duct -simple gland -compound gland
simple gland Ductal portion: one unbranched duct Different of secretory portion: 1- tubular 2- coild tubular 3- branched tubular 4- acinar (alveolar)
Compound gland Ductal portion: Have branched duct (repeadly) Secretory portion: 1- tubular 2- acinar 3- tubulo – acinar
methods of secretory products 1-merocrine 2-holocrine 3-apocrine
character of secretory cell: 1-polarity: 2- innervation: sensation nerve ending 3- nutrition: no blood vessel (diffusion) 4- renewal: cell + mitotic activity: rate variable 5- metaplasia: physiological or pathological condition