chapter 3 epithelial tissues. overview 4 main types of tissues in the human body what is a tissue? 4...
TRANSCRIPT
Chapter 3
Epithelial tissues
Overview
4 main types of tissues in the human body What is a tissue?
4 TYPES
Epithelial tissue
Connective tissue
Muscular tissue
Nervous tissue
Structure and Function
Epithelial tissue provides coverings and linings
provide protection Allow for diffusion, filtration and osmosis Secretion, transport, absorption
Basic structure
Epithelial cells are packed close together Little intercellular material between them Form continuous sheets with no blood
vessels
That is why epithelial tissues provide good coverings
Shape and Arrangement
Epithelial cells are classified according to the shape of the shell and how they are arranged
Shape of Cells
Squamous: flat and scale-like
Cuboidal: cube shaped
Columnar: higher than wide
Transitional: varying shapes that can stretch
Arrangement of Cells
Simple: single layer of cells of the same shape
Stratified: many layers of cells, named for the shape of the cells in the outer layer
Pseudostratified: appears to be layered, but is not
Attachment
Epithelial tissues attach to other tissues
A basement membrane forms at the bottom of the tissue
Generally this then attaches to a connective tissue
Simple Squamous Epithelium
Single layer, very thin
Substances can easily pass through
Diffusion of gases occurs easily
Example: alveoli (tiny air sacs in lungs) and the linings of blood vessels and lymphatic tissue
Stratified Squamous Epithelium
Several layers of closely packed cells
Protection
Examples; epidermis, lining of mouth
Simple Columnar
Single layers Higher than wide (columns) specialize in absorption Open spaces; goblet cells Goblet cells make mucus
Simple Cuboidal
Does not form coverings
Forms clusters of tubules Tubules secrete
Example; gland tissue and the secretion of hormones
Transitional epithelium
Several layers and has the ability to stretch Bladder tissue When cells stretch, they flatten out
Psuedostratified
Appears to be two layers thick, but is not
Cilia extend from from cells
Allow rapid movement of substances
Line the trachea (rapid removal of dust)
Make a chart to study
List category of tissues List each type Describe it’s structure List it’s function Give one or two examples of where it is
located in the human body Use the chart to make a matching quiz for
yourself