This document discusses the four main types of tissues in animals: epithelial, connective, muscular, and nervous tissue. It provides details on the structure and function of each type of tissue. Epithelial tissues cover surfaces and organs and protect the body. Connective tissues connect and support other tissues. Muscular tissues allow for movement and include cardiac, smooth, and skeletal muscle. Nervous tissue forms the brain, spinal cord, and nerves to regulate body functions and transmit nerve impulses.

2. TISSUE
“Tissues are group of cells that have a similar structure and act together to
perform a specific function .
The word “tissue” derives from the French word “tissu”, meaning that something
that is “woven” from the verb tisser, “to weave”.

3. ANIMAL TISSUE
The animal cells are grouped together to form animal tissues. These tissues vary in
their structure, function, and origin.
There are four different types of tissues in animals.
 Epithelial Tissues
 Connective Tissues
 Muscular Tissues
 Nervous Tissues.
The study of animal tissues is known as “histology”

4. 1) EPITHELIAL TISSUES
They cover the body , organs ,blood vessels and all body cavities.
The cells are thin and lower most layer rest in a basement membrane.
There are different types of epithelial tissues which are named according to the
number of layers they form and the shape of the individual cells that make up those
layers .ie,
 Simple epithelium : A single layer of cells

5.  Simple squamous epithelium : flattened cells.
 Simple cuboidal epithelium : cells that are cube –shaped.
 Simple columnar epithelium: vertically elongated cells .
 Ciliated epithelium: epithelial cells that contain many tiny hair- like Projections.

6. FUNCTIONS
Provides a barrier between the external environment and the organit covers.
Specialised to function in secretion and absorption.
Protects organisms from microorganisms , injury and fluid loss.
Excretes waste products such as sweat from the skin.

7. 2) CONNECTIVE TISSUES
It is a biological tissue that is important in supporting , connecting or separating
different types of tissues and organs in the body.
All connective tissue is made up of cells , fibres (such as collagen) and
extracellular matrix.
Bone, blood, fat, and cartilage are all connective tissues.

8. FUNCTIONS
They attach organs and tissues together.
They help in repairing tissues.
They prevent the organs from mechanical shocks.
They store fat in the form of adipose tissues.
The organs also help in defence.

9. 3) MUSCULAR TISSUES
Muscle cells form the active contractile tissues of the body known as muscle tissue
or muscular tissue.
The muscular tissue develops from the mesoderm of the embryo.
It is characterized by properties that allow movement

10. Muscle tissue is classified in to three types according to structure and function.ie,
i. Cardiac muscle : They are located in the walls of the heart. Appear striated,
under involuntary control.
ii. Smooth muscle : Located in the walls of hollow visceral organs. Appear
spindle – shaped, and also under involuntary control.
iii. Skeletal muscle : It occur in muscles which are attached to the skeleton .
They are striated, and under voluntary control.

11. FUNCTIONS
It helps in movement and locomotion.
It supports the bones and other structures.
It responsible for peristalsis and parturition.

12. 4) NERVOUS TISSUES
It is the main component of the nervous system ,which include the brain, spinal
cord , and nerves.
It is made up of the nerve cells (neurons).
Contain two distinct cells - neurons and glial cells.
It consists of the dendrites ,cell body, axon, and nerve endings.

13. FUNCTIONS
Regulate and controls body functions.
Generates and transmits nerve impulses.
Supports , insulates and protects impulse generating neurons.
Responds to stimuli.