Animal Tissue Epithelial tissue Connective tissue Muscle tissue Nervous tissue.
Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141...
Transcript of Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141...
![Page 1: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/1.jpg)
Epithelial tissue and its variations
141
![Page 2: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/2.jpg)
Definition Avascular tissue Cells are closely apposed and adhere to
each other by cell junctions They exhibit functional and
morphological polarity They are attached to basal lamina
![Page 3: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/3.jpg)
Classification according to function
Covering and lining epithelial tissue– Protection– Absorption– Transportation
Secretory – glandsReceptor – sensory organs Contractile (myoepithelial cells)
![Page 4: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/4.jpg)
Cell polarityApical domainLateral domainBasal domain
Functionally different = specialized surfaces
Cell junctions divide cell membrane into apical and basolateral region
![Page 5: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/5.jpg)
The apical domain modifications
Microvilli – frequent in all cell types – sign of absorption – brush border (striated border)
Stereocilia – – Male genital system – extremely long
and branching microvilli– Sensory hair cells – derived from
microvilli - mechanoreceptorsCilia – motile cilia, primary cilia (sensoric),
nodal cilia
![Page 6: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/6.jpg)
MicrovilliActin filaments 20-30 –
anchored to membrane by villin
Crosslink by actin bundling proteins
Terminal web – actin, spectrin, myosin II
![Page 7: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/7.jpg)
Brush border
Enlargement of apical domain
Enzymes, carrier proteins, ion channels
Glycocalyx
Occurence : enterocyte, cells of proximal tubule in kidney
![Page 8: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/8.jpg)
Stereocilia
Extremely long microvilli – resorption – actin,
α actinin instead of villin
![Page 9: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/9.jpg)
Stereocilia in sensory hair cells of inner ear
Mechanoreceptors – actin and espin crosslink
Structure is similar to microvilli
![Page 10: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/10.jpg)
Cilia
Kinocilia and flagella – axonema – 9+2 microtubules + dynein
Primary cilia – immobile – lack of motor-proteins.
• Sensoric function – chemoreceptor, osmoreceptor, mechanoreceptor
• Primary cilia of developing cells are essential for normal morphogenesis
Nodal cilia – bilaminar embryonic disc – primitive node - similar to primary cilia but wit ability of rotational movement
![Page 11: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/11.jpg)
KinociliaLength 5-10μm Axonema: 9 duplets A13,
B10 + 2 central microtubules
Basal body = centriol – 9 triplets
Basal foot and striated rootlet – coordination of ciliary movement and anchorage to cytoplasm
![Page 12: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/12.jpg)
Primary cilia9+0Lack of motor-
proteinand central pair of
microtubulesBasal body Primary cilia
formation is synchronized with cell cycle progression and centrosome duplication events
Receptor:Rods and conesHair cells of inner earOlphactory
epitheliumlMechanoreceptor – in
ducts of glands – control of Ca++ in cell – polycystic kidney disease, retinitis pigmentosa
![Page 13: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/13.jpg)
Nodal cilia
9+0, but motile!!!Rotational
movementMechanim
generating the right-left asymetry
![Page 14: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/14.jpg)
Lateral domain modification
• Junctional complex:• zonulae occludentes
– tight junctions• zonulae adherentes• maculae adherentes
(desmosomes)• gap junctions• Lateral infoldings
(plicae), interdigitations
![Page 15: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/15.jpg)
Intercellular cohesiveness is established by cell-to-cell adhesive molecules
• CAM – cell adhesion molecule• Cadherins - transmembrous proteins
(intracellular domain is bound to the cytoskeleton, actinu/intermediate filaments, extracellular domain fills up the intercellular space)
• Disorder: lost of cohesiveness – invasiveness of tumor cells
![Page 16: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/16.jpg)
Zonula occludens – tight junction
Apical region of the junclional complex
Diffusion barrier Separation of apical
and lateral domains
Occludins and claudins
-anastomosing belts - actin
![Page 17: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/17.jpg)
Anchoring (adhesive) junctions - zonula adherens
E-cadherin, Catenin, vinculin +
α-actininActin
Ca++ dependent
![Page 18: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/18.jpg)
Anchorin junctions- desmosome
Desmocollins and desmogleins
Intermediate filaments (cytokeratins)
Ca++ dependent
![Page 19: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/19.jpg)
Communicationg junctions – gap junction (nexus)
Accumulation of transmembrane channels or pores – connexons – inchange of molecules between cells - signaling
![Page 20: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/20.jpg)
Basal domain – basal labyrint
Enlargement of basal surface + mitochondria
= Absorption of ions – Na/K ATPase and sodium pump
Occurence – proximal and distal tubules of kidney
![Page 21: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/21.jpg)
Basal domainAttachment to the
extracellar matrix (focal adhesions – FAK and hemidesmosomes) - integrins
Focal adhesion – actin
Hemidesmosome - cytokeratin
![Page 22: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/22.jpg)
Basement membrane (LM) is the layer of extracellular material separating epithelia from the
connective tissue• Basal lamina and lamina reticularis • Basal lamina (EM): lamina densa and lamina
rara • Lamina rara: receptors for laminin and
fibronectin • Lamina densa : laminin + collagen IV,
proteoglycans and glycoproteins• Lamina reticularis: reticular fibres (collagen III),
anchoring fibrils (collagen VII), fibrilin
![Page 23: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/23.jpg)
Epithelial tissueCovering – cells are
polarized with free surface
Forming cords- no free surface – endocrine glands
Reticular – epitheloreticular cells - network - thymus
Secretory portion = parenchyma
![Page 24: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/24.jpg)
Classification of epithelial tissue (covering)
SimpleSquamousCuboidalColumnarPseudostratified
columnar
![Page 25: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/25.jpg)
Classification of epithelial tissue (covering)
StratifiedSquamous
• Keratinized• Nonkeratinized
CuboidalColumnarTransitional (Urothelium) -
![Page 26: Epithelial tissue and its variations - Univerzita Karlovavyuka-data.lf3.cuni.cz/CVSE1M0001/141 epithelial tissue... · 2014-10-17 · Epithelial tissue Covering – cells are polarized](https://reader034.fdocuments.us/reader034/viewer/2022042406/5f20d7cbed005415115336ef/html5/thumbnails/26.jpg)
Glands
Exocrine glands – secrete their product onto a surface
Secretory portion and duct – cells have a free surface
Endocrine – secrete their product (hormones) into the blood Cells with free
surface – thyroid gland
Cords of cells