Nervous system/ ‘2’ main parts Nervous system

Nervous system

Signals are sent from one region of the body to another via the intricate network of cells and fibers that makes up the nervous system. It is essential for regulating and coordinating a range of body processes and reactions to external stimuli. The two primary components of the nervous system are the peripheral nervous system (PNS) and the central nervous system (CNS) (PNS).

The nervous system can be divided into two main parts:

1.Central Nervous System (CNS):

The central nervous system (CNS) is a major division of the nervous system and consists of the brain and spinal cord. It serves as the main control center for the entire body, processing and integrating information from the peripheral nervous system (PNS) and coordinating various physiological functions. Here are the key components and functions of the central nervous system:

  1. Brain:

    • The brain is the most complex organ in the body and is responsible for higher cognitive functions, emotions, and voluntary movements.
    • It is divided into several regions, each with specific functions. These regions include the cerebral cortex (responsible for conscious thought and voluntary actions), the cerebellum (involved in coordination and balance), the brainstem (regulating basic life functions like breathing and heartbeat), and the limbic system (associated with emotions and memory).
  2. Spinal Cord:

    • The spinal cord is a long, cylindrical structure that extends from the base of the brain through the vertebral column.
    • It acts as a communication pathway between the brain and the rest of the body. Sensory information from the PNS is transmitted to the brain via the spinal cord, and motor commands from the brain are sent to muscles and glands through the same pathway.
    • The spinal cord also plays a crucial role in reflex actions, which are rapid and automatic responses to specific stimuli that don’t involve conscious thought.
  3. Protection and Support:

    • The CNS is well-protected by various structures. The brain is surrounded by the skull, providing a physical barrier. The spinal cord is encased in the vertebral column, offering protection.
    • Meninges, a set of membranes, cover and protect the brain and spinal cord. Cerebrospinal fluid, found in the subarachnoid space, cushions and supports the CNS structures.
  4. Information Processing:

    • The CNS processes information from sensory organs, allowing perception of the environment.
    • It integrates and interprets this information, making decisions and coordinating appropriate responses.
    • Motor commands are then sent from the CNS to effectors (muscles and glands) to carry out specific actions.

Disorders of the central nervous system can have profound effects on overall health and function. Neurological conditions such as strokes, neurodegenerative diseases (e.g., Alzheimer’s and Parkinson’s), traumatic brain injuries, and spinal cord injuries can impact cognitive abilities, motor control, and various bodily functions. Understanding the structure and function of the central nervous system is crucial for diagnosing and treating neurological disorders.

2.Peripheral Nervous System (PNS):

The Peripheral Nervous System (PNS) is one of the two main divisions of the nervous system, with the other being the Central Nervous System (CNS). The PNS consists of all the nerves and ganglia (clusters of nerve cell bodies) outside the brain and spinal cord. It plays a crucial role in connecting the CNS to the rest of the body, enabling communication between the central and peripheral parts of the nervous system.

The PNS can be further divided into two main functional components:

  1. Somatic Nervous System (SNS):

    • The SNS is responsible for voluntary movements and sensory input. It controls skeletal muscles and is involved in the conscious perception of sensory stimuli, such as touch, temperature, and pain.
    • Motor neurons of the SNS carry signals from the CNS to the skeletal muscles, causing them to contract and produce movement.
    • Sensory neurons of the SNS transmit information from sensory receptors in the skin, muscles, and joints to the CNS, allowing for the perception of the external environment.
  2. Autonomic Nervous System (ANS):

    • The ANS regulates involuntary bodily functions, including heartbeat, digestion, respiratory rate, and glandular activity.
    • It operates without conscious control and helps maintain internal balance (homeostasis) in response to changing external and internal conditions.
    • The ANS is further divided into two branches:
      • Sympathetic Nervous System (SNS): Activated in response to stress or danger, the SNS prepares the body for a “fight or flight” response by increasing heart rate, dilating pupils, and redirecting blood flow to vital organs.
      • Parasympathetic Nervous System (PNS): Activated during rest and relaxation, the PNS promotes “rest and digest” activities. It slows heart rate, stimulates digestion, and conserves energy.

Nerves in the PNS consist of bundles of axons (nerve fibers) that transmit signals to and from different parts of the body. These nerves can be sensory, motor, or mixed (containing both sensory and motor fibers). The PNS plays a crucial role in allowing the body to interact with its external environment and respond to various stimuli, contributing to overall bodily function and adaptability.

                                      The neuron, a specialized cell with the ability to transfer both chemical and electrical impulses, is the fundamental functional unit of the nervous system. Synapses, which are junctions where signals are transferred from one neuron to another, are the means by which neurons connect with one another. Neurons are supported and shielded by another type of cell in the nervous system called glial cells.

The nervous system is necessary for learning, memory, coordination, sensory perception, motor function, and the control of internal body functions. Disorders of the nervous system can have a wide range of impacts on physical and mental health, and they may include disorders such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and different neurological traumas.


To sum up, the nervous system is an intricate and vital network that makes it easier for every part of the body to communicate and coordinate. It is made up of the peripheral nervous system (PNS) and the central nervous system (CNS) and controls motor responses, sensory perception, and both voluntary and involuntary processes. The fundamental building blocks of the nervous system, neurons, communicate with each other through synapses to enable complex communication.

The brain and spinal cord make up the central nervous system (CNS), which controls cognitive processes and processing information. Connecting the central nervous system (CNS) to the rest of the body, the PNS, which includes the somatic and autonomic nervous systems, regulates both voluntary movements and involuntary functions such as digestion and heart rate. The sympathetic and parasympathetic branches of the autonomic nervous system further split, preserving a fine equilibrium in physiological processes.

The nervous system is essential for learning, flexibility, and internal stability. Health issues impacting this system can have a significant effect on both mental and physical well-being. Comprehending the nervous system’s complexities is essential to understanding human physiology and treating neurological disorders.

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