What is Tissue?
TISSUE is a collection of a large number of cells performing the same function.
Types and Function of Tissue
a. Epithelial Tissue
Here cells are very closely packed and the intercellular substance, called the matrix is minimal. These tissues cover the body, and line the cavities and tubes. Their functions are:
Protection of underlying structures.
In connective tissues, the cells are more widely separated from each other than the epithelial tissue. The intercellular substances are present in larger amounts. Their functions are mainly:
Binding and support
Various type of connective tissue are given below:
- Adipose Tissue consists of a collection of fat cells containing fat globules. Its function is to reduce heat loss through the skin, serve as an energy reserve & protection.
- Cartilage is a much firmer tissue than other connective tissues, and the matrix is quite solid. The cartilage is divided into three types: Hyaline, White fibrocartilage, Yellow or elastic fibrocartilage. The cartilages provide smooth surface for movement of joints, which ensures flexibility and support to the body.
- Blood is liquid connective tissue. The total volume of blood constitutes approximately 8% of the body weight or 5.6 liters.
- Bone is the hardest connective tissue in the body and when fully developed it is composed of: Water 25% Organic material 30% Inorganic salts 45% The bones provide movement, support and protection to the various organs of the body. They store essential minerals needed for maintaining body functions. Blood cells like RBCs & platelets are manufactured in the bone marrow.
c. Muscle Tissue
There are three type of muscle tissue:
- Smooth / Involuntary muscles are found in walls of blood vessels, abdominal & pelvic organs. The contraction of these muscles is not under the control of an individual. The smooth muscles are involved in the constriction of blood vessels & airways, propulsion of food along the G.I. tract, and in the contraction of the urinary bladder.
- Skeletal / Voluntary muscles these muscles are attached by tendons to the limbs & trunk. The contraction of these muscles is under the control of an individual. The skeletal muscles are involved in movement & posture of the body.
- Cardiac muscles are only present in the heart. They are involved in the pumping of blood to various parts of the body.
d. Nervous Tissue
These tissues are present in the nervous system, and the cells are known as NEURONS or nerve cells. They are involved in the transmission of impulses and other complex body mechanisms.