Flashcards
Epithelial Tissues - Structure & Function
Cards in this deck (20)
- 1What are epithelia?Cells that cover or line the body surfaces, tubes & cavities. They form the interface between different physiological fluid compartments
- 2Characteristics of epithelia• intimate contact between cells may be connected via tight junctions
• separated from underlying tissues via a basement membrane
• undergo rapid division every 4 days to replace lost cells - 3How is epithelia classified?By SHAPE - squamous, columnar or cuboidal
By NUMBER OF LAYERS - simple or stratified
+ Transitional epithelia
By FUNCTION - 4Characteristics or simple epithelia• all cells are in contact with the lumen & BM
• found at sites of diffusion, absorption or secretion - 5Characteristics of stratified epithelia• cells in contact with the lumen = APICAL
• cells in contact with the BM = BASAL
• found at sites where there is need for protection from abrasion, infection or caustic content - 6Give an example of each type of epitheliaSIMPLE:
• squamous = blood vessels
• columnar = kidney tubule
• cuboidal = GI tract
STRATIFIED:
• squamous = skin
• columnar = reproductive system
• cuboidal = respiratory system
TRANSITIONAL = bladder - 7Functions of epithelia, the type required & an example location for eachEXCHANGE - simple squamous e.g. lungs or blood vessels
TRANSPORT - simple cuboidal or columnar e.g. intestines or kidneys
CILIATED - simple cuboidal or columnar e.g. trachea or female reproductive tract
PROTECTIVE - stratified squamous e.g. skin & mouth
SECRETORY - simple or stratified columnar e.g. exocrine & endocrine organs - 8Characteristics or simple squamous epithelium• single layer of flattened cells with a central nucleus
• pavement-like appearance of irregularly shaped cells
• no gaps between cells - 9What is the specific name given to epithelium lining: 1. Body cavities? 2. Blood vessels?1. Mesothelium
2. Endothelium - 10Advantage of simple columnar epithelia in the small intestineIncreases surface area for absorption & mucus secretion to lubricate gut contents
- 113 levels of folding used to increase surface area1. Large folds
2. Microscopic villi
3. Microvilli - 12What surface modifications exist on simple columnar epithelia & what are there purposes?1. Microvilli form a brush boarder on the apical surface to which mucus can adhere
2. Goblets cells release mucus to lubricate the gut contents
3. Basement membrane separates the tissue layers - 13How is respiratory epithelia described?Pseudo-stratified ciliated columnar epithelium
- 14Characteristics & main locations of stratified squamous non-ketatinsied epithelium• flattened cells that undergo desquamation - basal cells then divide & move up to replace the lost cells
• wet epithelium
• found in the lining of the oesophagus, mouth, vagina & anal canal - 15Characteristic of & main location of stratified squamous ketatinsied epithelium• resits water loss - subject to abrasion
• skin - 16Characteristics of transitional epithelium• high numbers of tight junctions - prevent leakage
• elasticity - cells become more squamous as destination of the organ (bladder) occurs - 17What membrane protein is involved with: 1. Gap junctions? 2. Tight junctions?1. Connexin - important for communication
2. Claudin & occludin - prevents free movement - 182 forms of transport across the epithelium1. Trans-cellular transport
2. Paracellular transport - 19Roles of the tight junction1. BARRIERS - separate compartments
2. FENCES - maintain the asymmetrical distribution of lipids & proteins in the apical & basal membranes
3. GATES - selective movement - 20What are membrane proteins in between the apical & basal membranes referred to as?Baso-lateral proteins
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- MD2001 Flashcards on Epithelial Tissues - Structure & Function, created by Lareyna Mcmenemy on 15/07/2018.
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- Lareyna Mcmenemy
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