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HUMAN TISSUESby: pr ,Dr, Sanaa El-Sherbiny

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Tissue:A definition

Types of tissues

A group of connected, interdependent cells

thatcooperate to performa specific function

1. Epithelial Tissue

2. Connective Tissue3. Muscle Tissue

4. Nervous Tissue

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Epithelial Tissues

General Features1- Cellular Layer + Basement Membrane

2- Not Penetrated By Blood Vessels ,getBlood supply from underlying C.T.

3- but nerve fibers ramify between cells.

4- Rapid Rate of Cell Regeneration.

5-Embriologically derived from ectoderm,

mesoderm or endoderm.

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Special Characteristics of

Epithelia

Figure 4.1

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**Structural ClassificationAccording tonumberof layers andCell Shapes: *2 types ,simple&stratified.

**Funct ional C lass if icat ion :1-covering-epith.

2-glandular-epith.

3-neuro-epith.

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Classifications of Epithelia

stratified simple

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Simp le ep i thel ium

One layer of cells on a basementmembrane

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SIMPLESquamus.epithelium

**structure:one layer of flatcells on a basement membrane**Sites

LungALVEOLI

ENDOTHELIUM LINING THE BLOOD ANDLYMPHATIC VESSELS

SEROUS MEMBRANES LINING BODYCAVITIES

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Simple Squamous Epithelium

Figure 4.3a

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simple cuboidal

epithelium

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** formed of one layer of cubical cellson a basement membrane

LINING THE FOLLICLES IN THETHYROID GLAND

DUCTS OF medium sized glands

SECRETORY ACINI OFMANY GLANDS

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Simple Columnar Epitheliumone layer of columnar cells on a basemen

membrane

Figure 4.3c

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simple columnar epithelium non

modified,lining ducts of glands Modified:- absorptive ,small intestine

- secretory,stomach.

- ciliated,uterus and fallopian tubtube

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Simple Columnar Absorptive

Epithelium

Function: AbsorptionLocation: Digestive Tract

Microvilli

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Pseudostratified Columnar

Epithelium

One layer of overcrowded cells with

many levels of nuclei

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Pseudostratified Ciliated ColumnarEpithelium lining tracheaand bronchi

Figure 4.3d

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Stratified Epithelium

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Stratified Squamous Epithelium

Function:Protection

(st.sq.keratinized)

Locations:

epidermis of

the skin

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Stratified Squamous Epithelium

Many layers Basal one columnar

Intermediate layers

Polygonal in shape

Upper layers are

squamous

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Stratified Squamous Epithelium

nonkeratinized mouth cavity

Figure 4.3e

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Transitional Epithelium

Figure 4.3h

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TRANSITIONAL EPITH.

many cell layers -

stretch

cube-shaped andelongated cells

line urinary

bladder, ureters,and part of urethra

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Transitional Epithelium

6-8 layers in empty

bladder

2 layers in full one

Basal layer columnar

on ill defined b.m

Intermediate layers

polygonal

Upper layer largemay be bi-nucleated

Second layer flask

shaped covered with

mucous like

protective layer

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GLANDULAR EPITHELIUM

THE CELLS ARE SPECIALISEDFOR SECRETION.

ACCORDING TO NUMBER OFSECRETORY CELLS WE HAVE:

UNICELLULAR GLANDSAS

GOBLET CELLS.

MULTICELLULARGLANDS ASSALIVARYGLANDS.

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Uni-cellular glands as

GOBLET CELLS.

Multi-cellular

gland

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1-ACCORDING TO

SECRETORY

PASSAGES A-EXOCRIN GLANDS:

Have duct system

SUCH AS :salivary glands.

-ENDOCRINE GLANDS:

No ducts ,secrete directly into theblood

SUCH AS:THE PITUITARY

GLAND.

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2-ACCORDING TO TYPE

OF SECRETION MUCOUS GLANDS:SUBLINGUAL.

SEROUSGLANDS:PAROTID.

MUCOSEROUS GLANGSUBMANDIBULAR.

CERUMINOUS:EXTERNAL AUDITORY

GLANDS.

MILKY:MAMMARY GLANAS.

Oily :sebacious glands

CELLULARGLANDS:TESTIS,OVARY.

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4-ACCORDING TO SHAPE OF

SECRETORY PART ALVEOLARGLANDS:

AS MAMMARY GLANDS.

Tubular GLANDS

AS GASTRIC GLANDS

TUBULO-ALVEOLARGLANDSAS SALIVARY GLANDS

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EXOCRINE GLAANDS

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NEURO EPITHELIUM

THE EPITHELIAL CELLS ARESPECIALIZED FOR RECEPTION

OF

EXTERNAL STIMULI SUCH AS:

RETINA OF THE

EYE,OLFACTORY

MUCOSA,TASE BUDS and ORGAN

OF CORTI .

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TASTE BUDS Are neuro-epithelial structures formed of:

1- Sensory cells.

2- Supporting cells.

3- Basal stem cells for regeneration of all

Types of cells.

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Taste buds

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Olfactory epithelium

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THANK YOU