Body Tissues Flashcards
What is a biological tissue?
Group of cells that have a similar structure & function as a unit
What is intracellular matrix?
Non-living material between cells, abundant in some tissues & sparse in others, may contain unique salts/fibres to that tissue
What are the 4 main tissues?
Epithelial, connective, muscle, nervous
A note on Epithelial Tissue
> Widespread - covers all body surfaces, hollow organs, body cavities, & tissue glands
Protection, secretion, absorption, excretion, filtration, diffusion, & sensory reception
Cells packed close with little intercellular matrix
1 free surface not in contact with other cells - attached to underlying connective tissue by a non-cellular basement membrane
E.g. skin
Explain the basement membrane?
Thin, pliable, sheet-like extracellular matrix - provides cell & tissue support - platform for complex signalling - sits between epithelial & connective tissues
What 3 factors are epithelial cells classified by?
Shape, stratification & specialisation
What shapes can epithelial cells be?
Squamous, cuboidal, columnar, transitional
Explain squamous epithelial cells’ shapes
Flat, irregular shape
Explain cuboidal epithelial cells’ shapes
Width is the same as height - nuclei at centre of the cell
Explain columnar epithelial cells’ shapes
Taller than they are wide - nucleus closer to base of cell
Explain transitional epithelial cells’ shapes
Found lining stretchy organs - bladder lining & ureters in mammals
What is simple stratification?
1 layer of cells
What are stratified cells?
> 1 layer of cells, superficial layer used for classification, only one layer touches the basement membrane, withstand larger amounts of stress
What are pseudostratified cells?
Only occurs with columnar cells - only a single layer of cells - nuclei positioned in manner suggestive of stratified epithelial
