A tissue is described as a bunch of cells which are alike in arrangement and work in unity to perform a particular function in a body. A cellular organizational level between cells and an entire organ may be a tissue. Fun fact : The word tissue comes from a form of an old French verb “tisser” which means “to weave”. The group of cells work in conjunction in a coordinated way to support the specific functions of a tissue. A nonliving material fills the spaces between the cells and it is called the intercellular matrix.
These tissues are divided into four main types in the body: epithelial, connective, muscle, and nervous. Each and every one of these tissues have specific characteristics and vital functions of their own.
Epithelial Tissue
Epithelial tissues are widespread throughout the body. They form the protective layer of every surface on the body,lining the cavities of the body and hollow organs, thus making it the major tissue in glands. Epithelium also lines internal passageways like the chest, brain, eye, inner surfaces of blood vessels, the heart, and therefore the internal ear . Epithelial cells come in structures of squamous, cuboidal, or columnar. These cells are spread out in single or multiple layers. Given below are the important characteristics of epithelial tissues:
These can be single-layered or multi-layered.
The tissues have the power to regenerate.
These are held in place together by gap junctions, tight junctions, zonula adheren, desmosomes, or interdigitation.
The cell wall of those cells is specialized into flagella, cilia, and microvilli.
It is also responsible for monitoring and controlling the permeability of substances which may enter or leave the body.
The epithelium also accommodates glands and discharges substances such as sweat or digestive enzymes. It also produces other substances into the blood (hormones), such as the thyroid, pancreas , and pituitary gland.
Types of epithelium tissues are :
Simple cuboidal epithelium.
Simple columnar epithelium.
Pseudostratified columnar epithelium.
Connective Tissue
Connective tissues have various functions. The main function of this sort of tissue is that the communication between the central systema nervosum with the peripheral systema nervosum . The connective tissues possess more intercellular substances comparatively than the other tissues. The connective tissue plays a vital role as it supports most organs because the tissue includes blood, bone, cartilage, adipose (fat) and the fibrous and areolar (loose) connective tissues. Given below are the following functions of connective tissues :
The organs and tissues are connected together because of these sets of tissues.
They perform the task of accumulating fat in the form of adipose tissues.
They provide aid by repairing tissues.
They ward off mechanical shocks from having an impact on the organs.
It is made up of 3 kinds of fibres :
Collagenous fibers
Elastic fibers
Reticular fibers
Muscle Tissue
Muscle tissue is a combination of cells that execute the special function, which is to shorten or contract in order to bring about movement of the body parts. Muscle cells are elongated and slender, so they are called muscle fibers. When a stimulus is received by an end of a muscle cell, a wave of excitation is passed through the entire cell in order to allow all the parts to contract in harmony. They are arranged in bundles and surrounded by connective tissues. Muscular tissue performs the following functions:
It supports the bones and other structures.
It helps in movement and locomotion.
- It supports the bones and other structures.
- It is responsible for peristalsis.
There are three types of muscle cells:
Skeletal muscle
Cardiac muscle
Smooth muscle
Nervous Tissue
The location of the Nervous tissue is in the brain,nerves , and spinal cord. It makes up the peripheral and the central nervous system. It is specialized with a capability to conduct electrical impulses and convey information from one area of the body to a different . It acquires the potential to launch and transmit the nerve impulse. The coordinating and controlling many body activities is the responsibility of the nervous tissue. It encourages muscle contraction, enables in creating an awareness of the environment, and assists in playing a major role in emotions, reasoning, and memory. Characteristics Of Nervous Tissue :
Nervous tissue constitute the CNS and PNS of the nervous system
Contains two distinct cells – neurons and glial cells
It consists of the dendrites, cell body, axon and nerve endings.
Nerve impulses are carried out and generated by Neurons. They produce and generate electrical signals that are transmitted across distances, they do so by secreting chemical neurotransmitters.
Responds to stimuli.
Carries out communication and integration.
Provides electrical insulations to nerve cells and removes debris.
Transfers messages to the cell body from the neurons.
Types of nervous tissues are :
Motor nerves
- Sensory nerves
- Autonomic nerves.
