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بسم الله الرحمن الرحيم. EPITHELIAL TISSUE. EPITHELIAL TISSUE. 1- Epithelial membranes (Epithelia). 2- Glands. EPITHELIAL TISSUE. General characteristics: 1- Have cells with little intercellular space. 2- are avascular. 3- Are separated from the underlying C.T.
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EPITHELIAL TISSUE • 1- Epithelial membranes (Epithelia). • 2- Glands.
EPITHELIAL TISSUE • General characteristics: 1- Have cells with little intercellular space. 2- are avascular. 3- Are separated from the underlying C.T. by the basement membrane. 4- Apical surface modifications: a- Microvilli (brush border). b- Cilia. 5- Are derived from ectoderm, endoderm or mesoderm.
Parameters for classificationof epithelial membranes • (1) The shape of most superficial cells: a- squamous (flat) b- cuboidal c- columnar
(2)The Number of cell layers: a- Simple b- stratified
(3) Function: a- Protection b- Absorption c- Secretion d- Excretion e- Transport f- Sensory reception
TYPES OF EPITHELIAL MEMBRANES • (A) Simple Epithelium: 1- Simple squamous epithelium 2- Simple cuboidal epithelium 3- Simple columnar epithelium: a- with cilia b- without cilia 4- Pseudostratified columnar epith.: a- with cilia b- without cilia
TYPES OF EPITHELIAL MEMBRANES • (B)Stratified epithelium: 1- Str. Squamous epith. 2- Str. Cuboidal epith. 3- Str. Columnar Epith. 4- Transitional epith.
SIMPLE EPITHELIUM D. Pseudo-stratified columnar epith.
STRATIFIED EPITHELIUM XXXXXXXXXXXXXX C. Str. Cuboidal epith. D. Str. Columnar epith.
Simple squamous epithelium Endothelium
CLASIFICATION OFGLANDS Glands are classified according to the following parameters: • Presence or absence of ducts: Exocrine. Endocrine. (2) No. of cells: Unicellular: e.g. Goblet cell. Multicellular.
CLASIFICATION OFGLANDS (3) Nature of secretion: Serous: serous acini Mucous: mucous acini Seromucous: Seromucous acini Aqueous (watery) Fatty Waxy
CLASIFICATION OFGLANDS (4) Mechanism of secretion: a- Merocrine (by exocytosis) b- Apocrine c- Holocrine
CLASIFICATION OF EXOCRINEGLANDS (5) Branchingof duct & Shape of secretory unit: - Simple - Simple branched - Compound branched - Tubular - Alveolar (acinar) - Tubuloalveolar
SEROUS, MUCOUS & SEROMUCOUS ACINISEROUS DEMILUNEMYOEPITHELIAL CELLS