Textus epithelialis tpn Jelnek
Epithelial tissue Textus epithelialis tpn Jelnek Characteristic of epithelium
cells foundation is basal lamina minimum of extra cellular matrix plenty of intercellular junctions various shapes important for classification variability of functions Basal lamina thin layer of extracellular matrix two layers
collagen IV. type, laminin, proteoglycans two layers lamina rara, lamina densa lamina reticularis part of connective tissue foundation for epithelial cells produced by epithelial, muscular, Schwanns cells and adipocytes Basement membrane two connected basal laminae
on the border of two epitheliums lung, kidney two laminae rarea, one lamina densa basal lamina and lamina reticularis visible in light microscope PAS positive Function of basal lamina
barier selection in transport - proteoglycans selection of cells laminin regeneration wound healing, NM junction polarisation and migration of epithelial cells Polarity apical part of cell basal (basolateral) part of cell
lumen of organ, surface of organ basal (basolateral) part of cell basal lamina in contact with lamina propria Lamina propria contains vessels and nerves
mechanical support of epithelium connects epithelium to another layers usually undulated surface - papillae Specialisations of cellular surface
free surface microvilli, stereocilia, cilia lateral surface intercellular junctions, interdigitations basal surface connection with BL, basolateral labyrinth Microvilli, stereocilia, cilia
non-branching projections of cell enlargement of cell surface stereocilia branched non motile projections cilia non-branching motile projections transport of extracellular mass Intercellular junctions
adhesive zonula adherens (belt desmosome) desmosome (macula adherens) hemidesmosome occluding zonula occludens (tight junction) communicating gap junction (nexus) Intercellular junctions (belt)
Zonula occludens cell. membranes without intercell. space five layers of membrane Zonula adherens intercell. space about 20 nm thicker membrane connected with cytoskeleton Intercellular junction (spot)
Desmosome intercell. space about 30nm sometimes dark plate connected with cytoskeleton hemidesmosome connection between cell and BL Nexus (gap junction) intercell. space about 2 nm connexons forms pores for ion transport Regeneration of epithelium
fast and complete faster with complete BL continual regeneration of cells stem cells small intestine 3 days skin - 27 days Types of epithelial cells
transporting cells signalising cells synthesizing and exporting cells myoepithelial cells stem cells Transporting cells cells transporting ions (active)
microvilli, basolateral labyrinth prox. a dist. tubule of kidney, striated ducts of sal. gl. cells transporting using pinocytosis transport of larger molecules pinocytic sacs endothelium Signalising cells release signal molecules neurocrine cells (neurons)
distribution across synapse paracrine cells (DNES) distribution diffusely to ECM secretory granules in basal part of cell endocrine cells (suprarenal) distribution - transport by blood stream ultrastructure depends on type of substance Synthesising and trasporting cells
proteins synthesis, modification, storage serous cells of sal. gl., serous cells of pancreas glycoproteins of mucus mucus (lighter than cells prod. proteins) mucous cells of sal. gl., goblet cells steroids lipid droplets, sER, tubular MIT Myoepihelial cells cytokeratins, contractile microfilaments
acins and tubules of sweat, salivary, lacrimal gl. Stem cells maternal undiferetiated regeneration of epithelium Classification of epitheliums
acording to spatial arrangement flat trabecular reticular according to function Flat epithelium according to count of layers
simple stratified pseudostratified, transitional according to shape of cells squamous cuboidal columnar keratinised and non-keratinised Single layered squamous Single layered cuboidal Single layered columnar Single layered columnar with cilia Pseudostratified with cilia Stratified squamous Transitional O2 muscular artery O1 - kidney O3 thyroid gland O4 - colon O5 uterine tube epidydimis O6 - esophagus O7 - skin V10 - trachea O8 urinary bladder Trabecular epithelium
cells in cords cords form web between cords are capillaries, nerves liver, adrenal, pituitary E8 - adrenal AZAN Reticular epithelium cells are in contact only with their processes
cells form web in holes of web are other cells thymus, bone marrow Classification according to function
epithelium covering - skin epithelium resorbtional - intestine epithelium respiratory - lung epithelium sensory olfactory ep. epithelium muscular myoepithelial c. epithelium germinal testes epithelium secretory - glands Glandular epithelium cells producing and releasing substrate
this substrate is used by organism type of secretion merocrine (pancreas) apocrine (mammary gland) holocrine (sebaceous gland) Types of gland exocrine endocrine excretion to lumen of organ
have ducts endocrine do not have ducts excretion to blood capillaries Types of exocrine glands
according to shape of secretory and excretory parts simple glands compound glands tubular alveolar (acinar) tubulo-acinar O9 glandula sublingualis O10 - pancreas The end