الله بسمالرحيم الرحمن

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. 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.

MICROVILLI

CILIA

SIMPLE EPITHELIUM

D. Pseudo-stratified columnar epith.

STRATIFIED EPITHELIUM

C. Str. Cuboidal epith.D. Str. Columnar epith.

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Simple squamous epithelium

Endothelium

Simple squamous epithelium

Simple cuboidal epithelium

Simple cuboidal epithelium

Simple Columnar Epithelium

Pseudostratified columnar epithelium

Non-keratinized Stratified Squamous epithelium

Keratinized stratified squamous epithelium

Transitional Epithelium

GLANDS

CLASIFICATION OF GLANDS

Glands are classified according to the following parameters:

(1) Presence or absence of ducts: Exocrine. Endocrine.(2) No. of cells: Unicellular: e.g. Goblet cell. Multicellular.

CLASIFICATION OF GLANDS

(3) Nature of secretion:

Serous: serous acini

Mucous: mucous acini

Seromucous: Seromucous acini

Aqueous (watery)

Fatty

Waxy

CLASIFICATION OF GLANDS

(4) Mechanism of secretion:

a- Merocrine (by exocytosis)

b- Apocrine

c- Holocrine

CLASIFICATION OF EXOCRINE GLANDS

(5) Branching of duct & Shape of secretory unit:

- Simple

- Simple branched

- Compound branched

- Tubular

- Alveolar (acinar)

- Tubuloalveolar

TYPES OF EXOCRINE GLANDS

GOBLET CELLS

GOBLET CELLS

GOBLET CELLS

GOBLET CELLS

MAJOR SALIVARY GLANDS

SEROUS, MUCOUS & SEROMUCOUS ACINISEROUS DEMILUNE

MYOEPITHELIAL CELLS

SEROUS ACINAR CELL

SEROUS ACINI

MUCOUS ACINI

MUCOUS ACINI

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