epithelium - doctor 2017 - ju medicine€¦ · surface (2) goblet cells. 3/12/2018 ... it consists...
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EPITHELIUM
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري2
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري3
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري4
1- SIMPLE SQUAMOUS EPITHELIUM
It is a single layer of flat cells
that resembles a tiled floor
when viewed from apical
surface; centrally located
nucleus that is flattened and
oval or spherical in shape.
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري5
A) Forms the epithelial
layer of
serous membranes
a- PERITONEUM
b-PLEURA
c-PERICARDIUM
where it is called
Mesothelium
Most common locations of the simple squamous epithelium
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري6
Simple squamous epithelium, mesovarium, human, H&E
centrally located
nucleus that is
flattened and oval
or spherical in
shape
Facilitates the movement of
the viscera
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري7
(B) lines the cardiovascular and lymphatic system
(heart, blood vessels, lymphatic vessel linings),
where it is known as
ENDOTHELIUM
Provides a physical barrier
between
the circulating blood and the
subendothelial tissues
Produces vasoactive agents that
cause
Constriction and relaxation
of underlying vascular smooth
muscles, thus affecting
the blood pressure!!!!!
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احسان العمري8
(C)-Alveoli (air sacs of lungs) of lungs
diffusion of oxygen into
blood vessels of lungs)
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري9
glomerular
(Bowman’s)
capsule of
kidneys
Present at sites of filtration
(such as blood filtration in kidneys)
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري10
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري11
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري12
Single layer of
cube-shaped
cells;
round, centrally
located nucleus.
Cuboidal cell
shape is obvious
when tissue is
sectioned and
viewed from the
side
Its main
functions are
Secretion and
absorption.
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري13
❖lines kidney tubules
❖Makes up secreting portion of some glands such as
thyroid gland
❖Ducts of some glands such as pancreas
❖The smallest conducting bronchioles of the lung
Locations of the simple cuboidal epithelium
Surface of Ovary
lines anterior surface of capsule of lens of the
eye
forms pigmented epithelium at posterior
surface of retina of the eye
Read only
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري14
lines kidney tubules
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري15
cuboidal cells (CC).
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري16
This photomicrograph
shows two pancreatic
ducts (PD) that
are lined by a simple
cuboidal epithelium
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري17
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3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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CILIATED SIMPLE COLUMNAR EPITHELIUM Single layer of ciliated
column like cells with
oval nuclei near base of
cells. Goblet cells are
usually interspersed
among ciliated columnar
epithelia
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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❖Lines some bronchioles (small tubes) of respiratory tract
❖Uterine (fallopian) tubes
CILIATED SIMPLE COLUMNAR EPITHELIUM
Locations of the
Some paranasal sinuses
Central canal of spinal cord
Ventricles of brain
Read only
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري20
Cilia help move oocytes
expelled from ovaries
through uterine
(fallopian) tubes into
uterus
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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SIMPLE COLUMNAR NONCILIATED
Single layer of nonciliated
column like cells with
oval nuclei near base of cells;
contains
(1) columnar epithelial cells
with microvilli at apical
surface
(2) goblet cells
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري22
Location Lines gastrointestinal tract (from stomach to anus), ducts of many
glands, and gallbladder
Function Secretion
and absorption; larger
columnar cells contain
more organelles and
thus are capable of
higher level of
secretion and
absorption than
are cuboidal cells
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E.Pseudostratified columnar
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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Pseudostratified epithelium:(pseudo= false)
• Tissue appears to be several layers but is really a single layer.
• Cells nuclei lie at different levels and cells appear to have multiple layers.
• All its cells rest on the base but not all of them reach the surface.
3/12/2018 امجد الشطرات و احسان العمري.ماهر الحديدي د. درويش بدران د. د 24
1. Ciliated: Form of cells with cilia and Goblet cells.
• Locations: Lines airways of most of upper respiratory tract.
• Functions: Secretes mucus that traps foreign particles.
2.Nonciliated: Contains cells without cilia and lack goblet cells.Locations: Lines larger ducts of many glands & epididymis.
Functions: Absorption and protection.
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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➢ Two or more layers of cells
➢ cells in apical layer and several layers deep to it are squamous cells in deeper
layers vary from cuboidal to columnar.
➢ As basal cells divide, daughter cells arising from cell divisions push upward
toward apical layer.
➢ As daughter cells move toward surface and away from blood supply in
underlying connective tissue, they become dehydrated and less metabolically
active.
➢ Tough proteins predominate as cytoplasm is reduced, and cells become tough,
hard structures that eventually die.
➢ At apical layer, after dead cells lose cell junctions they are
sloughed off, but they are replaced continuously as new cells emerge from basal
cells.
Stratified epithelium
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II. Stratified epithelium
Types:
a. Stratified squamous• keratinized
• Nonkeratinized.
b. Stratified cuboidal epithelium.
c. Stratified columnar epithelium.
d. Transitional epithelium.
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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A-Stratified squamous epithelium
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري
Two types:•Keratinized (dry).
•Nonkeratinized (wet).
Keratinized stratified squamous epithelium develops tough layer of keratin in
apical layer of cells and several layers deep to it
(Keratin is a tough, fibrous intracellular protein that helps protect skin and
underlying tissues from heat, microbes, and chemicals.) Relative
amount of keratin increases in cells as they move away from nutritive blood
supply and organelles die
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Keratinized stratified squamous :
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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• Covers dry surfaces such as epidermis of skin (superficial layer of the skin). Formtough layer of keratin (tough protein) between surface cells.
• Functions:
Protect skin and underlying tissues from heat, microbes, chemicals and water loss.
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Nonkeratinized stratified squamous
• Surface layers contain small amount of keratin and always wet.
• Location: Lines wet surfaces as lining of mouth, esophagus, part of epiglottis, part of pharynx, and vagina) and covers tongue
• Function: Protection against scratch, water loss, ultraviolet radiation, and foreign invasion.
• Both types form first line of defense against microbes.
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري31
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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STRATIFIED CUBOIDAL EPITHELIUM
Location Ducts of adult sweat glands and
esophageal glands, part of male urethra.
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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Basal layers usually consist of shortened,
irregularly shaped cells; only apical layer has
columnar cells; uncommon.
STRATIFIED COLUMNAR EPITHELIUM
Location Lines part of urethra;
large excretory ducts of some
glands, such as esophageal
glands; small areas in anal
mucous membrane;
part of
conjunctiva of eye.
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TRANSITIONAL EPITHELIUM
• Locations: Urinary bladder, ureter.
• Functions: Allow the organ to stretch and protection from rupturing.
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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➢ Variable appearance (transitional)
➢ In relaxed or unstretched state, looks like stratified cuboidal epithelium, except apical layer
cells tend to be large and rounded.
➢ As tissue is stretched, cells become flatter, giving the appearance of stratified squamous
epithelium.
➢ Multiple layers and
elasticity make it ideal for lining hollow structures (urinary bladder) subject to expansion from
within
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري35
Location Lines urinary bladder and portions of
ureters and urethra
Function Allows
urinary organs to
stretch and maintain
protective lining while
holding variable
amounts of fluid
without rupturing
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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is a disorder of the small intestine in which one of the
first pathologic changes
is loss of the microvilli brush borderof the absorptive cells
This is caused by
an immune reaction
against the wheat protein gluten during its digestion, which
produces diffuse enteritis (intestinal inflammation), changes
to the epithelial cells leading to malabsorption, and eventually
to pathologic changes in the intestinal wall.
The malabsorption
problems and structural changes
are reversible
when gluten is removed from the diet.
Celiac disease
also called gluten-sensitive enteropathy
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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Several mutations have been described in the proteins of
the cilia and flagella. They are responsible for the immotile
cilia syndrome (Kartagener syndrome), whose symptoms
are chronic respiratory infections caused by the lack of the
cleansing action of cilia in the respiratory tract and
immotile
spermatozoa, causing male infertility
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري38
➢ Sometimes termed basket cells
➢ Fusiform or stellate in shape
➢ Contain actin and myosin filaments and contract
when stimulated by nervous or endocrine signals.
➢They surround the secretory portions and ducts of
some glands, e.g.mammary, lacrimal, salivary and
sweat glands
➢Their contraction assists the initial flow of
secretion into larger conduits.
Myoepithelial cells
3/12/2018امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
احسان العمري39
surface epithelium and its underlying connective tissue are regarded as a functional unit
called a membrane.
40امجد الشطرات و .ماهر الحديدي د. درويش بدران د. د
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Mucus membrane, also called mucosa, lines those cavities that connect
with the outside of the body, namely, the alimentary canal, the respiratory
tract, and the geni-tourinary tract. It consists of surface epithelium (with or
without glands), a supporting connective tissue called the lamina propria,
Serous membrane, also called serosa, lines the peritoneal, pericardial, and pleural
cavities. These cavities are usually described as closed cavities of the body, although in
the female the peritoneal cavity communicates with the exterior via the genital tract.
Structurally, the serosa consists of a lining epithelium, the mesothelium, a supporting
connective tissue, and a basement membrane between the two. Serous membranes do not
contain glands, but the fluid on their surface is watery.
The two types of membrane are mucus
membrane and serous membrane.
3/12/2018