ANHB1101 Lecture Notes - Lecture 23: Microvillus, Keratin, Transitional Epithelium
3 Jun 2018
School
Course
Professor
Lecture 23
Sunday, 1 May 2016
1:12 pm
Tissues and Epithelia
Tissues:
• Types of cells that make up tissues
o Squamous
o Cuboidal
o Columnar cells
• Tissues - groups of cells that are similar in structure and perform a common
function
• 4 primary tissue types are found in the body
o Epithelia - covering
o Muscular - movement
o Nervous - control
o Connective - support
Characteristics of Epithelia:
• Covering, lining and glands - barriers
• Highly cellular
• Form sheets - allowing to cover and line
• Cell to cell contact - specialised
• Polarity
• Free surface - open to a space inside the body, all epithelia has a free surface
• Basement membrane (basal lamina) - closest to the bottom of the epithelia,
acellular structure containing protein/polysaccharide complexes
• Lateral surfaces - in a single layer, will be in contact with the adjacent cells
• All sit on a layer of connective tissue - do not have blood vessels so connective
tissue supports them and provides nutrients/takes away waste via diffusion
• Vascularity and innervation
• Good at regeneration - divide very well
Glands:
• Dividing of epithelial cells
• Poke down into underlying connective tissue
• May keep a duct to the surface
• Originated from epithelial cells
Cell-Cell Junctions:
• Epithelial cells - tightly junctions
• Make the cells pin onto each other tightly
• Forces substances to pass through cells, not between
• Desmosomes - cells tightly bound to each other
• Gap junctions - small substances pass between adjacent cells
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