Tissues Of the Body

BASICS OF GENERAL
HISTOLOGY
Dr.Mohammed Shamiah
Introduction
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The human body is composed of approximately 200
distinctly different types of cells.
These cells are organized into four basic tissues that,
in turn, are assembled to form organs.
A basic knowledge of the general characteristics and
cellular composition of these tissues is essential
in histology, which is the study of tissues at the
microscopic level.
Dr.Mohammed Shamiah
Tissues Of the Body
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Tissues are groups of similar cells performing a
common function.
There are four types of tissue:
1-Epithelium tissue
2-Connective tissue
3-Muscular tissue
4-Nervous tissue
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Dr.Mohammed Shamiah
1-Epithelial tissue
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Functions of epithelial tissues:
1-Protection: against injuries, bacteria, chemical& water as
epithelium of skin & stomach
2-Secretory: as glandular epithelium of pancreas, prostate, salivary
& endocrine glands
3-Absorption: intestine & kidney
4-Sensation: taste buds & organ of corti
5-Reproduction: as the cells of testis & ovary
6-Excretion: as the cells of kidney & sweat gland
7-Covering:surface as skin lining cavities as stomach
8-Respiration: as the epithelium of lung alveoli
Dr.Mohammed Shamiah
1-Epithelial tissue
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Types of epithelial tissue:
A) Simple epithelial (cellular sheets formed of one (layer
of cell)
B) Stratified epithelium (formed of many layers of (cells)
Dr.Mohammed Shamiah
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C) Glandular epithelium (cells collected to form (gland)
D) Neuro-epithelium (epithelial cells act as
(receptors)
Dr.Mohammed Shamiah
Naming Epithelia
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Naming the epithelia includes both the layers (first) and
the shape of the cells (second)
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i.e. stratified cuboidal epithelium
The name may also include any accessory structures
Goblet cells
 Cilia
 Keratin
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Special epithelial tissues (don’t follow naming convention)
Psuedostratified
 Transitional
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Dr.Mohammed Shamiah
A-Simple Epithelium
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Types of simple epithelium:
1-Simple squamous
2-Simple cubical(Cuboidal)
3-Simple columnar (ciliated or not)
4-Pseudostratified columnar (ciliated or not)
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Dr.Mohammed Shamiah
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Dr.Mohammed Shamiah
1-Simple Squamous Epithelium
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Formed one layer of flat cells with flattened nuclei.
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Thin smooth lining to blood vessels to allow easy
passage of blood.
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It covers the peritoneum to facilitate the movements of
the viscera.
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It facilitates the active filtration of urine in kidney.
Dr.Mohammed Shamiah
Location:
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a) The endothelium of heart& blood vessels
b) The mesothelium of serous membranes as pleura,
pericardium, peritoneum(around intestine)
c) Outer layer of bowman's capsule of kidney.
d) Present in alveoli of lung
e) It covers the adult ovary
Dr.Mohammed Shamiah
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Dr.Mohammed Shamiah
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2-Simple Cubical
(Cuboidal)epithelium
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Formed of one layer of cubical cells with central round nuclei.
Function: secretion, excretion, covering &lining
Location :
1-lining of thyroid follicles
2-kidney lining tubules
3-in eye covering the anterior surface of lens & inner cells of
choroids
4-In glands: lining the acini & small ducts of glands
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Dr.Mohammed Shamiah
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Dr.Mohammed Shamiah
3- Simple Columnar Epithelium
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One layer tall columnar cells with basal oval nuclei.
Function: columnar epithelium secretion, absorption &
protection.
Location :
a) Stomach cell secrete mucin cells have clear cytoplasm
B) Intestine dark cytoplasm(absorption processes)
covered microvilli which are rich in phospholatase enzymes
facilitate absorption processes
micovilli are composed of microfilments
c) Lining of gall bladder, common bile duct& pancreatic duct
d) Lining of large collecting tubules of kidney
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Dr.Mohammed Shamiah
-Simple columnar ciliated Epithelium
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Surface are covered with cilia.
Cilia function: responsible for transport of solid or fluid
particle, they help in sensory reception.
Location :
a- Fallopian tube & uterus to facilitate the movements of ova
b- Outer or boney part of Eustachian tube
c- Some bronchioles of the lung
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Dr.Mohammed Shamiah
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Dr.Mohammed Shamiah
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4-Pseudo-stratified columnar (ciliated
& Non-ciliated)
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It's simple type of epithelium formed on layer of columnar cells
clear wavy basement membrane
The Basement Membrane is formed of
1-Reticular lamina: reticular tissue under epithelium
2-Basal lamina: formed of the cell membrane of basal cells
which is formed glycoprotein
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The surface may be ciliated or non-ciliated, cilia may be motile
or non motile(sterile)
Goblet cells may be present between the columnar cells
Dr.Mohammed Shamiah
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1-Pseudostratified columnar ciliated
with goblet cell & motile cilia
Location:
a) Upper respiratory passages
(nasal air sinuses, nasopharnx, lower part of larynx,
trachea & bronchi)
b) Lacrimal sac
c) Eustachian tube
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Function:
Protection, secretion& transport particles out the air
passages
Dr.Mohammed Shamiah
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2-Pseudostratified ciliated but the cilia are
not motile(this is not cilia but are tall solid
microvilli):
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This type present in epididymis
3-Pseudo-stratified columnar Non-ciliated
epithelium :
Present:
a-Upper part of vas deference & male urethra
b-Large ducts of salivary gland
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Dr.Mohammed Shamiah
2-Stratified Epithelium
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Is formed of many layers of cells
(3 or more layers)
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Types of stratified epithelium :
1- Stratified squamous epithelium
2- Stratified cuboidal epithelium
3- Stratified columnar epithelium
4- Transitional epithelium
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Dr.Mohammed Shamiah
1-Stratified Squamous epithelium:
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Have thick type of stratified epithelium formed of
many layers
5-30 layers of the cells
The cells rest on clear wavy basement membrane,
under the basement membrane there is C.T. containing
blood & lymph vessels
Dr.Mohammed Shamiah
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The surface may be covered with fresh nonkeratinized squamous cells as in esophagus.
Skin epithelium is covered by keratin layer so called
keratinizing stratified squamous.
The intermediate layers are polygonal cells(have
many sides)with desmosomes.
Dr.Mohammed Shamiah
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The superfacial layers of cells are flat squamous
cells which may be nucleated or not nucleated .
Sites of stratified squamous epithelium:
A-keratinizing stratified squamous epithelium in dry
surfaced areas:
- epidermis of skin.
- opening up on the skin
(external ear, external nose& outer surface of the lip)
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Dr.Mohammed Shamiah
B-Non Keratinizing stratified squamous
epithelium(wet areas)
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a) Oral cavity, inner surface of the lip, palate tonsils
b) Esophagus ,oropharnx & vocal cords
c) Cornea &conjunctive
d) vagina terminal parts of male & female urethral&
anal canal
Dr.Mohammed Shamiah
2-Stratified Cuboidal Epithelium
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Is covered by cuboidal
Cells.
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Location :
In the duct of sweat glands ,semiferous tubules of
the testis
Dr.Mohammed Shamiah
3-Stratified Columnar Epithelium
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Layers less in number
The superfacial cells are non-keratinizing columnar
cells
Location:
1-Conjunctiva of the eye.
2-Membranous &penil part of male urethra.
3-Large ducts of glands.
4-Recto-anal junction.
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Dr.Mohammed Shamiah
-Stratified Columnar Ciliated Epithelium
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It formed of few layers of cell.
The superficial cells are non-keratinzing , columnar
ciliated cells.
Location :
1-Foetal esophagus.
2-Nasal surface of soft palate.
3-Laryngeal surface of epiglottis.
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Dr.Mohammed Shamiah
4-Transitional Epithelium
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Present in the urinary bladder tract
The epithelium rests on a thin basement membrane
The superficial cells are covered with mucous-like
substance which forms a protecting membrane
Dr.Mohammed Shamiah
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Transitional epithelium may be formed of 3-4
layers only in full distended urinary bladder, 6-8
in an empty bladder.
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The superfacial cells may changes temporarily into
squamous cells when the bladder is full of urine
Dr.Mohammed Shamiah
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Location :
1-Minor&major calyces of kidney.
2-Pelvis of the ureter, urinary bladder.
3-The prostatic part of male urethra &inner part of
female urethra.
Dr.Mohammed Shamiah
C-Glandular Epithelium:
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Cells that are specialized to produce and secrete
substances into ducts or into body fluids.
Dr.Mohammed Shamiah
Classification of glands:
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1-According to the presence or absence of duct
systems.
2. According to the mode of secretion.
3. According to the type of secretory product.
4-According to the shape of the ducts and the shape of
secretory portion .
5- According to their function.
Dr.Mohammed Shamiah
1-According to the presence or absence
of duct systems:
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a-Endocrine:
• secreting hormones directly in the blood.
• as: thyroid , parathyroid, pituitary, suprarenal, pineal
body: islets of langherhans, placenta, testis, ovary
b-Exocrine glands:
• They have ducts to carry their secretion
• as: salivary glands, sweat& sebaceous glands
c-Mixed glands:
• Posses the exocrine & endocrine function
• as: pancreas, testis, ovary
Dr.Mohammed Shamiah
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2. According to the mode of
secretion:
a-Merocine glands:
there is no cellular change in their secretory
cells ex. Salivary glands
b-Apocrine glands:
secretory product of the glands ex.mammary glands(secret
milk)
c-Holocrine gland:
sebaceous glands may come out with their secretion
Dr.Mohammed Shamiah
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Dr.Mohammed Shamiah
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3. According to the type of secretory
product:
a-Serous secretory glands: as parotid glands, vonEbner gland of the tongue
b-Mucous secretory glands: brunner’s glands &
goblet cell
c-Mucoserous gland: submandibular &
sublingual glands
d-Fatty secretory glands: sebaceous glands
e-Watery secretory glands: sweat glands
f-Waxy secretory gland: glands of external ear
g-Cellular secretory gland: testis & ovary
Dr.Mohammed Shamiah
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Dr.Mohammed Shamiah
4-According to the shape of the ducts
and the secretory portion:
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A-Tubular glands
B-Acinar glands
C-Tubulo-acinar glands
Dr.Mohammed Shamiah
A-Tubular glands
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Dr.Mohammed Shamiah
B-Acinar glands
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Dr.Mohammed Shamiah
C-Tubulo-acinar glands
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Dr.Mohammed Shamiah
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Dr.Mohammed Shamiah
5- According to their function:
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A-Secretory glands:
Synthesize specific substances to be secreted
in the body as salivary &endocrine glands.
B-Excretory glands:
Eliminate & excrete the waste produced out
side the body as kidney & sweat gland
Dr.Mohammed Shamiah
4-Neuro-Epithelium:
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The epithelial cells acts as sensory receptors for
special stimuli
 They provided with small hair (hairlets) on their free
surfaces, while their bases are surrounded with
sensory nerves
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They found in
1.
Tongue- taste buds
2.
Internal ear-organ of Corti (hearing)
3.
Internal ear-crista ampularis (equilibrium)
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Dr.Mohammed Shamiah
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Thank you
Dr.Mohammed Shamiah