Nervous tissue is one of the four types of animal tissue, along with epithelial tissue, connective tissue, and muscle tissue. Nervous tissue is composed of two main types of cells: neurons and glial cells. Nervous tissue is present in the brain, spinal cord, and nerves all around the body. Nervous tissues perform many important functions, such as movement, thought, and memory.
Components of Nervous Tissues
1. Neurons
Neurons are specialised nerve cells that form the structural and functional units of the nervous system. They are responsible for receiving, processing, and transmitting nerve impulses throughout the body, enabling communication between different parts of the body.
- Axon: Nerve cells or neurons, all of which comprise an axon. Axons are long, stem-like projections arising out of the cell because neuron communication between the cells occurs, subsequently passing driving forces.
- Cell Body: The central part of the neuron is the cell body, which contains the nucleus, cytoplasm, and cell organelles.
- Dendrite: Dendrites are short, branched extensions that receive signals from other neurons and transmit them to the cell body.
2. Glial Cells
Glial cells, also known as neuroglia, are non-neuronal cells of the nervous system that provide support, protection, and nourishment to neurons. Although they do not conduct nerve impulses, glial cells are essential for the proper functioning and maintenance of the nervous system.
- They are non-excitable cells and do not conduct electrical impulses.
- They provide structural support and protection to neurons.
- They are more numerous than neurons in the nervous system.
- They have the ability to divide and regenerate, unlike neurons.
Types of Neurons
When the nerves get an electrochemical signal (neurotransmitter) or any impulse from the stimulus, nerves start functioning by responding via getting a signal from the brain in response to the stimulus. Based on their function, nerves are classified into different types of nerves:
1. Motor Nerves
Motor neurons, also known as motor nerves, are responsible for transmitting signals as far as possible from the spinal cord and brain to all of the body's muscles.
- The impulse helps people to do normal activities like talking, walking, drinking water, squinting their eyes, sitting, sleeping, and so on.
- If any damage to the motor neurons then it can cause weakness of muscle or contraction of the muscles.
- The sciatic nerve empowers the full leg to move which the help of different nerves. A couple of these motor nerves work in the hamstring, feet, thighs, and feet.
2. Sensory Nerves
The sensory nerves or sensory neurons create impulses or signals in the opposite direction from another kind of nerve known as the motor neurons. Features of Sensory Nerves are given below:
- The sensory neurons assemble information like pressure, pain, temperature, and so forth from the sensors that are available in the muscles, skin, and other internal organs, which thus divert it back to the brain and spinal cord.
- Numbness, pain, tingling sensations, and hypersensitivity are all symptoms of damage to the sensory nerves.
- The sense neurons assemble information like pressure, pain, temperature, and so forth from the sensors that are available in the muscles, skin, and other inward organs which thus divert it back to the brain and spinal cord.
3. Interneuron
An interneuron is a type of neuron that acts as a link between sensory neurons and motor neurons within the central nervous system (CNS). It plays a key role in processing, interpreting, and integrating information before an appropriate response is generated. Features of Interneuron are given below:
- Located entirely within the brain and spinal cord
- Short axon with many dendrites
- Highly involved in information processing
- Also called association neurons
Characteristics of Nervous Tissue
The following are the characteristics of Nervous tissue:
- Nervous tissue comprises the CNS and PNS of the nervous system.
- Contains two particular cells: neurons and glial cells
- Dendrites, cell bodies, axons, and nerve terminals are all part of the nervous tissue.
- Neurons' axon terminals release neurotransmitters, which further activate the dendrites of another neuron.
- The presence of specialisation at axonal terminals is called a synapse.
- Nerve cells have a long life, and can't be separated and replaced (except memory cells)
Location of Nervous Tissue
Nervous tissue may be found in peripheral nerves that travel throughout the body, as well as central nervous system components like the spinal cord and brain. The nervous tissue comprises nerve cells or neurons. Neurons are particular cells that respond to stimuli by creating signals through the axons, which are stretched extensions emerging from the cell body.
Functions of Nervous Tissue
The following are the Functions of Nervous tissue:
- Neuron generates nerve impulses. Neurons produce electrical signals, which transmit signals across distances. This is done by releasing neurotransmitters.
- Nervous tissue responds to stimulus.
- It carries out communication.
- Neuroglial cells provide support, insulation, and remove waste
- It carries the message from one part of the body.