Four Basic Tissues
Cell → Tissue → Organ → System → Body
1. Epithelial tissue (epithelium) – covers body
surface, lines body cavity, and forms glands – (free surface)
2. Connective tissue – underlies or supports the other
three tissues – dense, losse c.t.
3. Muscle tissue – made up of contractile cells and
responsible for movement – cardiac, skeletal, smooth m.,
4. Nerve tissue – receives, transmits, and integrates
informations from outside and inside the body to control the
activity of the body – PNS, CNS.
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Epithelial tissue
• Classification and characteristics of epithelial tissue
• Polarity of epithelial cells
• Surface modification of epithelial cells
a. Apical : cilia, microvilli, stereocilia
b. Lateral: intercellular junctions, interdigitations
c. Basal: basement membrane, hemidesmosome, focal
adhesion; basal striation (infolding).
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Characteristics of epithelium
• Avascular
• Minimal intercellular material
• Cells closely apposed with cell-to-cell adhesion
molecules --- cell junctions
– Creates a selective barrier between external
enviornment and the underlying connective tissue
• Functional and morphologic polarity – apical
domain, lateral domain, and basal domain
• Basement membrane – non-cellular, proteinpolysaccharide rich layer
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Classification of epithelial tissue (I)
Cell layers
Shape
simple
squamous
cuboid
stratified
pseudostratified
columnar
cuboid
columnar
transitional
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Classification of epithelial tissue (II)
Presence of apical surface modifications:
cornified (keratinizied) or noncornified
Cilia : ciliated or nonciliated
Microvilli : Striated border - intestine
Brush border - kidney (proximal tube)
Stereocilia: long microvilli – epididymis
(ductus defrence)
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Simple epithelium
• Simple squamous
• Simple cuboidal
• Simple columnar: apical surface
with modifications, e.g. ciliated,
striated border
• Pseudostratified columnar:
ciliated, stereocilia
Simple squamous epithelium: endothelium
Vascular system-endothelium
Exchange
Body cavities
Barrier
Bowman’s capsule (kidney)
Respiratory spaces (lung)
Silve stain of mesothelium spread preparation
Intercellular substance is stained in black by silver
Simple cuboidal epithelium
Small ducts of exocrine gland
Surface of ovary
Kidney tubules
Thyroid follicles
Absorption
Barrier
secretion
Simple columnar epithelium
Small intestine
Colon
Stomach lining and
gastric gland
Gallbladder
Absorption
Secretion
Colon (human)
: Goblet cell
GL: intestinal gland
Exocrine
Pancreas
(Monkey)
Simple columnar
Simple squamous
Simple cuboid
Epi-2010
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Pseudostratified columnar epithelium
with cilia
Trachea and bronchial tree
Efferent ductules of epididymis
Secretion
Absorption
Pseudostratified columnar epithelium
with stereocilia
Ductus deferens of epididymis
Secretion
Stratified epithelium
Stratified squamous:
Corninzed (keratinized) or
Noncorninzed (nonkeratinized)
Stratified cuboidal
Stratified columnar
transitional
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Noncornified stratified squamous epithelium
Epidermis
Oral cavity and esophagus
vagina
Barrier
protection
Cornified (Keratinized) stratified
squamous epithelium
Stratified cuboidal epithelium
Sweat gland duct
Large duct of exocrine gland
Anorectal junction
Barrier
conduit
Stratified columnar epithelium
Largest ducts of
exocrine glands
Anorectal juntion
Barrier
conduit
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Transitional epithelium
• Urinary tract
• Between stratified cuboidal to
stratified squamous
• The surface cells are large and pale
stained with a scalloped outline
• The luminal cell membrane appeared
thickened and densely stained
Transitional epithelium
Polarity
Apical domain
Lateral domain
Basal domain
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Apical domain
• Microvilli - regular & irregular
• Stereocilia - non-motile, long and
(Stereovilli)
irregular microvilli
• Cilia – motile, (9+2) doublets
primary (monocilia), (9+0) no active
nodal, (9+0) rotation
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Apical Domain and Its Modification
Microvilli – regular &
(1-3µm)
irregular (short)
Simple columnar epi.
with striated border
= microvilli
Kidney
Brush border
Intestine
Striated border
Striated border stained red by periodic acid
Schiff (PAS)– Glycocalyx of microvilli
Uterine gland
small projection
Syncytiotrophoblast (placenta)
irregular, branch
intestine
regular
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Microvilli - actin filament
+tropomyosin
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Stereocilia – long microvilli, irregular
(up to 120µm)
Epididymis – pseudostratified
columnar with stereocila
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Epididymis – pseudostratified columnar with stereocila : (absorption)
Stereocilia of the sensory epithelium of the ear :
sensory mechanoreceptors (vibration)
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Cilia – microtubule (axoneme)
recovery stoke
Trachea
pseudostratified effective stoke
ciliated epithelium
MTOC: microtubule organizing center
motor protein
(MTOC)
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Lateral surface: cell junctions
terminal bar (LM) = junctonal complex (EM) =
tight junction + intermediate junction + desmosomes
anchor
Terminal bar
-tight junction (zonula occuldens)
-intermediate (zonula adherens)
-macula adherens (desmosomes): mechanical
adhesion, composed of keratin filaments and
dense plaque
-gap junction (nexus): connexon
Terminal bars in pseudostratified epithelium
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Terminal Web & terminal Bar
terminal bar (LM) = junctonal complex (EM) =
tight junction (ZO) + intermediate junction (ZA) + desmosomes (MA)
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Tight junction-occluding junction
(zonula occuldens)
P phase
Zipper-like
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Zonula occludens strands proteins – occludins, claudins (aqueous
channels), JAM (Junctional adhesion molecule), ZO-1, ZO-2, ZO-3
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Claudin molecules (aqueous paracellular channels) , and complexity
and number of junctional strands, determine the permeability
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Anchoring junctions
Cell Adhsion
Molecules (CAMs)
Lateral surface
1. Zonula adherens –
(intermediate junction),
actin filaments
2. Macula adherens –
(desmosomes),
interact with
intermediate filaments
3. Focal adhesions –
(focal contact)
4. Hemidesmosomes
Basal surface
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Zonula adherens
( belt desmosomes, intermediate junction)
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=intermediate junction
= zonula adherens
=intermediate filament
+ microfilament
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Intercalated disk (閏盤) = fascia adherens + nexus
(belt desmosome)
(gap junction)
Cardiac muscle
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Macula adherens
(desmosome, spot desmosom)
Desmoplakin,
plakoglobin
“Cadherin zipper”
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Desmosomes; Nucleus
Intermediate filament
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Luminal surface
Occludin
lateral
Actin
filaments
E-cadherin
Keratin
filaments
Desmocollin
Desmoglein
Basal surface
Communicating junction:
Gap Junction (Nexus)
Gap junction (nexus): connexin, connexon,
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Epi-2010
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Lateral infoldings
(interdigitations)
Intestine
Gallbladder
-- Na+-K+ ATPase
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Basal domain and its specializations
in cell-to-extracellular matrix
• Basement membrane
• Cell to extracellular junction
• Basal membrane infoldings
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Basement membrane
H&E
PAS
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Basement membrane
1. Basal lamina -- lamina lucida (rara)
lamina densa
(fibronectin ,collagen, laminin, entactin/nidogen, proteoglycan)
2.
Lamina reticularis
Lamina rara
(lucida)
Lamina densa
Lamina
reticularis
Structure attachment, compartmentalization, filtration,
tissue scaffolding, regulation and signaling
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1
2
3
1
3
2
Basement membrane
Epi-2010
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Anchoring junction: Focal adhesion (contact) and hemidesmosome
Focal adhesion: dynamic
Focal contacts play an important
role in sensing and transmitting
signals from the extracellular
environment into the interior of the
cell. (mechanosensitivity)
Actin
Phosphotyrosine (a product of
tyrosine kinase reaction)
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Hemidesmosome: strong and stable adhesion
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Basal infolding of
plasma membrane
Basal striation of
proximal convoluted
renal tubule
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No duct
hormone
Pancreatic
acinar cell
lactating
sebaceous
gland (skin)
Unicellular
goblet cells
Multicellular
exocrine (intraepithelial, epithelial)
merocrine, apocrine, holocrine,
serous, mucous, mixed
paracrine
endocrine
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duct
secretary
Epi-2010
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Epithelial tissue
• Classification and characteristics of epithelial tissue
• Polarity of epithelial cells
• Surface modification of epithelial cells
Apical : cilia, microvilli, stereocilia
Lateral: intercellular junctions, interdigitations
• Termnal bar = junctioal complex
• Junctional complex: zonula occludens (tight junction),
zonula adherens (intermediate junction), macula adherens
(desmosome),
• Gap junction (nexus), lateral interdigitation
• Terminal web
• Basal: basement membrane, hemidesmosome, focal
adhesion; basal striation (infolding).
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