Chapter 7( Epithelial Tissues) Flashcards
What are cells ?
Cells are units of protoplasm surrounded by a plasma membrane.
nucleus separated from the cytoplasm by ?
A perforated nuclear membrane,
The nuclei of cells stain darkly with what?
haematoxylin and other basic dyes
the cytoplasm stains with what?
eosin
most tissues are com-plex, being made up of
several different kinds of cells.
What are the building blocks that form the organs?
Tissues
What is a simple tissue?
a group of cells of common origin having the same specialized structure, which fits them to perform a common function.
What are the 4 categories of tissue ?
Epithelial tissue (derived from all three germ layers)
Connective tissue (derived from mesoderm)
Muscular tissue (derived from mesoderm)
Nervous tissue (derived from ectoderm)
Epithelial tissue are derived from _____ germ layer
All three
Connective tissue are derived from _____ germ layer
Mesoderm
Muscular tissue are derived from _____ germ layer
Mesoderm
Nervous tissue are derived from _____ germ layer
Ectoderm
What is the arrangement of cells that made up the epithelium
closely packed and arranged in one or more layers.
Epithelial tissue is specialised to form
the covering or lining of all internal and external body surfaces.
Epithelial tissue that occurs on surfaces on the interior of the body is known as
endothelium.
Epithelial tissue is usually separated from the underlying tissue by
a thin sheet of connective tissue; basement membrane.
basement membrane provide what?
structural support for the epithelium and also binds it to neighbouring structures.
What are the two types of epithelia?
Covering epithelia and glandular epithelia..
Epithelial tissue can be divided into two base on cell thickness namely;
- simple epithelium.
- stratified epithelium.
What is a simple epithelium?
An epithelial tissue which is only one cell thick
What is a stratified epithelium.
An epithelial tissue which is two or more cells thick
Simple epithelium can be subdivided based on the shape of their into
- Squamous (pavement) epithelium.
- Simple Cuboidal Epithelium.
- Simple Columnar Epithelium
- Ciliated Columnar Epithelium
What is Squamous (pavement) epithelium?
Cells with appearance of thin, flat plates.
horizontal flattened, elliptical nuclei.
Where are the Squamous (pavement) epithelium found?
lining of cavities such as the mouth; blood vessels, heart and lungs and make up the outer layers of the skin.
What is Simple Cuboidal Epithelium?
roughly square or cuboidal in shape.
spherical nucleus in the centre.
Where are the Simple Cuboidal Epithelium found?
glands, in the lining of the kidney tubules as well as in the ducts of the glands and the germinal epithelium
What is Simple columnar Epithelium?
The cells are elongated and column-shaped.
The nuclei are elongated and are usually located near the base of the cells.
Where are the Simple culmar Epithelium found?
lining of the stomach and intestines, nose, ears and the taste buds of the tongue.
What are found between the columnar epithelial cells of the duodenum?
Goblet cells (unicellular glands)
Function of the Goblet cells (unicellular glands)
secrete mucus or slime, a lubricating substance that keeps the surface of the intestine smooth and protected.
What is a ciliated columnar Epithelium?
These are simple columnar epithelial cells, but in addition, they posses fine hair-like outgrowths, cilia on their free surfaces.
Ciliated epithelium is usually found in
the air passages like the nose. It is also found in the uterus and Fallopian tubes of females.
Classification Based on Cell Arrangement
- Simple epithelia: these are one cell thick.
- Pseudostratified epithelia: these are more than one cell thick but all the cells rest on the basement membrane.
- Stratified epithelia: these are many cells thick.
Classification Based on Cell Shapes
- Squamous epithelia: flattened cells shaped like paving stones.
- Cuboidal epithelia: isodiametric cells.
- Columnar epithelia: taller than they are wide.
- Transitional epithelia: change their shape when the epithelium is stretched.
There are _____ possible classes if the two schemes of classification are combined, but only _____ of them occur.
- twelve
- eight
