Download Epithelial Tissue

Epithelial Tissue
歐陽品教授
Epithelium
- covering the external surface or lining the internal cavity
- glandular epithelium
Classification of epithelia : based on the arrangement and shape of the cells
1. simple: consisting of one cell layer
squamous, cuboidal, columnar
2. stratified: only the shape of the cells forming the surface layer is for classification
squamous, cuboidal, columnar
3. transitional
4. pseudostratified columnar
Simple squamous (Pavement ) eipthelium
Simple cuboidal epithelium
Simple columnar (Absorptive) epithelium
Stratified (squamous) epithelium
Transitional epithelilum: Urinary epithelium
Pseudostratified (columnar) epithelium: respiratory epithelium
Basement membrane
- PAS positive in LM
- function as supporting mat and filtration or diffusion barrier
Intercellular junctions
1. Terminal bar (LM)
- junctional complex
(EM)
A. zonula occludens (tight junction)
B. zonula adherens (adherent junction)
C. macula adherens (desmosome)
2. Gap junction
Surface modification
1. Microvilli : contains a core of actin microfilament and related proteins
striated borders in intestine cells, brush borders in renal proxmial tubules
stereocilia in ductus epididymidis
stereocilia
2. cilia
Cilia
Cilia
Epithelial glands
1. Secretory cells in lining epithelium
a. unicellular gland: single cell in an epithelium, e.g. goblet cells
b. secretory epithelial layer
e.g. in stomach and uterus
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2. Structure distinct from lining epithelia
A. Exocrine gland
B. Endocrine gland
3. Manner of secretion
A. Merocrine secretion
- discharge of only secretory material without loss of any cytoplasm
e.g. most of secretory granules, small sweat gland
B. Holocrine secretion
- whole cell with secretory material are discharged, e.g. sebacous gland
C. Apocrine gland
- loss of apical cytoplasm with secretion, e.g. large sweat gland, fat droplet of
mammary gland
Holocrine secretion
Apocrine secretion
Merocrine secretion
Mucous cells
Serous cells
生技系 組織學實驗
Lab 1 : 顯微鏡及玻片CHECK IN
生技系 組織學實驗
Lab 2 : 上皮和腺體組織
Epithelial TISSUE
Dr. Pin Ouyang
Epithelium
- covering the external surface or lining the internal cavity
- glandular epithelium
Classification of epithelia : based on the arrangement and shape of the cells
1. simple: consisting of one cell layer
squamous, cuboidal, columnar
2. stratified: only the shape of the cells forming the surface layer is for classification
squamous, cuboidal, columnar
3. transitional
4. pseudostratified columnar
Basement membrane
- PAS positive in LM
- function as supporting mat and filtration or diffusion barrier
Intercellular junctions
1. Terminal bar (LM)
- junctional complex (EM)
A. zonula occludens (tight junction)
B. zonula adherens (intermediat junction)
C. macula adherens (desmosome)
2. Gap junction (communicating junction)
Surface modification
1. Microvilli : contains a core of actin microfilament and related proteins
striated borders in intestine cells, brush borders in renal proxmial tubules
stereocilia in ductus epididymidis
2. Cilia
Epithelial glands
1. Secretory cells in lining epithelium
a. unicellular gland: single cell in an epithelium
e.g. goblet cells
b. secretory epithelial layer
e.g. in stomach and uterus
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2. Structure distinct from lining epithelia
A. Exocrine gland
B. Endocrine gland
3.
Manner of secretion
A. Merocrine secretion
- discharge of only secretory material without loss of any cytoplasm
e.g. most of secretory granules, small sweat gland
B. Holocrine secretion
- whole cell with secretory material are discharged
e.g. sebacous gland
C. Apocrine gland
- loss of apical cytoplasm with secretion
e.g. large sweat gland, fat droplet of mammary gland
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Connective Tissue, Adipose Tissue and Cartilage
Dr. Pin Ouyang
Ingredients of connective tissue
A. connective tissue fibers
B. connective tissue cells
C. Ground substance (extracellular matrix)
A. Connective tissue fibers
1. Collagen (white) fiber, 1-10 m thick
- provide tensile strength and support
2. Reticular (argyrophil) fiber
- found in loose connective tissue, embryonic connective tissue and stroma of
hemopoietic and lymphatic tissues
3. Elastic (yellow) fibers, 0.2-1 m thick
- found in elastic arteries and elastic cartilage
B. Ground substance (extracellular matrix)
- histologically amphorous and consists of proteoglycan and glycosaminoglycan
- act as a diffusion medium of gas and metobolites for blood vessels and
tissues
C. Connective tissue cells
1. Fibroblasts
2. Mast cells
3. Macrophage
4. Plasma cells
5. Lymphocytes
6. Fat cells
Classification of connective tissue
A. Connective tissue proper
1. loose (areolar) connective tissue
2. dense irregular connective tissue
3. dense regular connective tissue
B. adipose tissue
a. white (unilocular) adipose tissue
b. brown (multilocular) adipose tissue
C. Special connective tissue
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Cartilage
1. cells: chondrocytes; derived from mesenchyme cells
2. extracellular matrix: stiff gel
fibers and ground substance
1. Hyaline cartilage
- location of hyaline cartilage:
fetal skeleton, trachae, nose, larynx, articular surface of long bone etc.
- structural components
A. perichondrium: dense fibroelastic tissue
- inner cellular layer containing chondroblasts
B. chondrocytes
- appearing as in lacunae due to cell shrinkage during preparation
2. Elastic cartilage
- location : external ear, Eustachial tube, epiglottis and larynx
- structural components
A. perichondrium
B. chondrocytes
3. Fibrocartilage
- intermedate form between cartilage and dense regular connective tissue
- location: intervetebral discs, pubis symphsis, knee joint and shoulder joint
Growth of cartilage
A. interstitial growth
cell divisions within lacunae: chondrocytes---> chondrocytes
B. appositional growth
- derivation of chondrocytes from chondroblasts in perichondrium
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Muscle Tissue and Bone
Dr. Pin Ouyang
Muscle
@ skeletal muscle (striated and volunteer)
1. nuceli: peripherally located, about 35 nuclei/mm of muscle fiber
2. myofibrils; composed of myofilments (1000-2000)
- dark band : A (anisotropic) band; thick and thin filaments
H band : middle of A band , no thin filament
- light band : I (isotropic) band: only thin filament
Z band: bisects I band
- sacromere: 2.5 um, between two Z bands
1. sacroplasm (cytoplasm between myofibrils)
- sacroplasmic reticulum : agranular ER, storage of calcium
2. sarcolemma (plasma membrane)
- covered with external lamina (basal lamina)
- transverse (T) tubule: invagination of sarcolemma
- triad: T tubule and adjoining sets of sacroplasmic reticulum
- motor end plate
@ cardiac muscle (striated and involunteer) : branching and united into a network
1. nucleus: centrally located, ovoid
2. myofibrils : form striation
3. sarcoplasm: abundant, sacroplasmic reticulum not associated with triad
4. sarcolemma : contain intercalated disc (junctional complex)
@ smooth muscle (non-striated and involunteer): elongated, tapering spindles
1. nucleus: centrally located and ovoid
2. myofibrils: not apparent in LM
3. sarcoplasm: scanty in amount
4. sarcolemma: thinner than that of skeletal muscle
Bone
@ preparation: 1. ground section
2. decalcification section
@ componets of bone
1. cells:
-
osteoblasts: differentiate form osteoprogenitor (mesenchyme) cells in the
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periosteum, produce osteoid matrix
-
osteocyte: from osteoblast, resides in lacuna and cell processes in canaliculi
- osteoclast: large, multinucleated cells, active site of resorption
2. bone matrix:
- organic substance (collagen fibers and ground substance)
- inorganic substance
3. surface tissue : periosteum
- contain dense irregular connective tissue and osteoprogenitor cells
@ Architecture
1. spongy (woven or non-lamellar) bone: formed by bone trabeculae
2. compact (lamellar) bone: space between trabeculae fill with lamellar bone
- Harversian system (osteon): contain concentric (Harversian) lamellae
and Harversian canal
- Volkmann’s canal
@ bone formation
1. intramembraneous bone formation
2.endochondral bone formation
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