2. By the end of the lesson the learner should be
able to;
i. Define the term tissue
ii. State the different tissues of the human body
iii. Describe the functions of the different types
of tissues.
3. What is a tissue?
• Tissue is a term used to describe a large
number of similar cells.
• Tissues are classified according to the size,
shape, and functions of their constituent cells.
• There are four types of tissues;
i. Epithelial tissue.
ii. Connective tissue.
iii. Muscle tissue.
iv. Nervous tissue.
4. Epithelial tissue
• This is the tissue that covers the body, and
lines cavities, hollow organs and tubes.
• Its also found in glands.
• The functions of epithelial tissues are;
I. Protection of underlying structures from
dehydration, mechanical and chemical
damage .
II. Secretion.
III. Absorption.
5. • The cells are packed closely together and the
matrix is minimal.
• The cells usually lie on a basement membrane
that is an inert connective tissue made up of
the epithelial cells.
• Epithelial tissues can be
I. Simple _ single layer of cells
II. Stratified _several layer of cells.
6. Simple epithelium
• Consists of a single layer of cells.
• They are usually found in secretory and
absorptive surfaces where the single layer
enhances this processes and rarely on areas of
stress.
• They are divided into three types and named
according to the shape of the cells.
7. Squamous epithelium
• Look like a pavement
• The cells fit closely together like flat stones,
forming a thin and very smooth membrane
across which diffusion occurs easily.
It forms the lining of the heart, blood vessels,
Lymph vessels, alveoli of lungs, and lining of the
collecting ducts of nephrones of the kidneys.
8. Cuboidal epithelium
• This consists of cube-shaped cells fitting
closely together lying on a basement
membrane.
• It forms the kidney tubules and is found in
some glands such as the thyroid
9. Columnar epithelium
• This is formed by a single layer of cells,
rectangular in shape, on a basement
membrane.
• The lining of the stomach is formed from
simple columnar epithelium without surface
structures.
10.
11. Stratified epithelia
• Stratified epithelia consist of several layers of
cells of various shapes.
• Basement membranes are usually absent.
• The main function of stratified epithelium
is to protect underlying structures from
mechanical wear and tear.
12. • There are two main types: stratified squamous
and transitional
13. Connective tissue
• Connective tissue is the most abundant tissue
in the body.
• The connective tissue cells are more widely
separated from each other than in epithelial
tissues, and matrix is present in considerably
larger amounts.
• There are usually fibres present in the matrix
14. • Major functions of connective tissue are:
i. binding and structural support
ii. protection
iii. Transport
iv. insulation.
15. Cells in connective tissue
• The different types of cell involved include:
i. fibroblasts
ii. fat cells
iii. Macrophages
iv. leukocytes
v. mast cells.
16. MUSCLE TISSUE
• Muscle tissue is a collection of cells which are
specialized to contract.
• Because of their ability to shorten muscles are
able to produce motion.
17. TYPES OF MUSCLE TISSUES
• There are three types of muscle tissues;
i. skeletal muscle
ii. Cardiac muscle
iii. smooth muscle
18. Skeletal Muscle Tissue
• The cells of skeletal muscle tissue are long and
cylindrical and have numerous nuclei.
Cardiac Muscle Tissue
The cells (muscle fibers) of cardiac muscle
tissue are short, branched, contain one
nucleus, and are striated.
19. Smooth Muscle Tissue
• The cells (muscle fibers) of smooth muscle
tissue are spindle-shaped, contain one nucleus,
and are non-striated.
Smooth muscle tissue is generally found in the
walls of hollow organs such as the organs of
the digestive and respiratory systems
20. NERVOUS TISSUE
• Nervous tissue is a collection of cells that
respond to stimuli and transmit information.
NERVOUS TISSUE CELLS
A neuron (nerve cell) is the cell of the nervous
tissue that actually picks up and transmits a
signal from one part of the body to another
21. • A synapse is the point at which a signal passes
from one neuron to the next.
• The neuroglia (also known as glia) is made up
of the supporting cells of the nervous system
(glial cells).
