Nervous Tissue And it's Types Complete Notes : हिन्दी And English
Nervous Tissue :-
- Nervous tissue is a specialized type of tissue found in the nervous system.
- It is composed of nerve cells called neurons and supportive cells known as glial cells.
- Nervous tissue plays a crucial role in transmitting and processing information throughout the body.
Functions of Nervous Tissue :-
1. Communication :- Nervous tissue enables rapid communication between different parts of the body, allowing for quick responses to stimuli.
2. Sensory Input :- It receives information from sensory organs, such as the eyes, ears, and skin, and transmits it to the brain for interpretation.
3. Integration:- Nervous tissue integrates incoming information and coordinates appropriate responses, helping maintain homeostasis.
4. Motor Output :- It sends signals from the brain to muscles and glands, enabling voluntary and involuntary movements.
Structure of Nervous Tissue :-
1. Neurons :- These are the building blocks of nervous tissue. Neurons consist of a cell body, dendrites (receiving single), and an axon (transmitting single). They conduct electrical impulses, allowing for communication within the nervous system.
Type of Neurons :-
A. On the basis of polarity :
a). Unipolar Neurons :- Unipolar neurons have a single process extending from the cell body, which then splits into two branches. One branch functions as a dendrite, receiving sensory information, while the other branch acts as an axon, transmitting signals to other neurons.
- It is found in Embryo of vertebrate.
b). Bipolar Neurons :- Bipolar neurons have two processes extending from the cell body—an axon and a dendrite—on opposite ends. The dendrite receives sensory input, while the axon transmits signals to other neurons.
- It is found in Retina of Eyes.
c). Multipolar Neurons :- Multipolar neurons have multiple processes, typically one axon and multiple dendrites, extending from the cell body.
B. On the basis of Myelin sheath :
a). Myelinated Neurons :- Myelinated neurons are characterized by the presence of a myelin sheath, which is a protective covering made up of fatty substances called myelin.
b). No myelinated Neurons :- No myelinated neurons, as the name suggests, lack a myelin sheath. Instead, they may have a thin layer of Schwann cells or other supportive cells that surround the axons.
2. Glial Cells :- Glial cells provide support and protection to neurons. They help maintain the proper environment for neuronal function and play a role in nerve repair.
Types of Nervous Tissue :-
1. Central Nervous System (CNS) :-
This includes the brain and spinal cord. It processes and integrates information, making decisions and coordinating responses.
2. Peripheral Nervous System (PNS) :-
It comprises nerves and ganglia located outside the CNS. The PNS transmits information between the CNS and the rest of the body.
Common Nervous Tissue Disorders :-
1. Alzheimer's disease :- Alzheimer's disease is like having a "forgetting" problem that gets worse over time. It starts slowly, with mild memory loss and confusion, and gradually progresses to more severe symptoms. People with Alzheimer's may have trouble remembering recent events, recognizing familiar faces, or finding the right words to express themselves.
2. Parkinson's disease :- Parkinson's disease can make it harder for a person to move smoothly and normally. It typically starts gradually, with symptoms like tremors (shaking), stiffness, and difficulty with balance and coordination. People with Parkinson's may have a slower gait and may experience muscle rigidity, making it harder to perform everyday tasks.
3. Multiple Sclerosis :- Imagine your body's nerves as electrical wires, and myelin is like the insulation that keeps the signals moving smoothly. In Multiple Sclerosis, the immune system damages or destroys this protective covering, disrupting the flow of electrical signals between the brain and the body.
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