The Nervous System

  • The nervous system is made up of two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord, while the PNS includes all nerves outside the CNS.

  • The main role of the nervous system is to coordinate and regulate the body’s responses to changes in the environment. It achieves this through the transmission of nerve impulses or signals.

  • The nervous system also plays a key role in homeostasis, the maintenance of a stable internal environment in the body.

  • Neurons or nerve cells are the basic units of the nervous system. They have unique structures - a cell body, dendrites and an axon - specially designed to transmit nerve impulses.

  • The process of transmission of a nerve impulse involves electrical and chemical changes. This is typically initiated by stimulus, transformed into an electrical signal that travels along the neuron, and eventually triggers the release of chemicals called neurotransmitters.

  • The synapse is the tiny gap between two neurons. It’s where the transmission of a nerve impulse from one neuron to another occurs through the action of neurotransmitters.

  • Reflex actions are rapid, automatic responses to stimuli. They enable the body to respond quickly to potentially harmful situations. They follow a specific pathway called the reflex arc.

  • The brain is divided into several parts including the cerebrum, cerebellum and medulla, each with specific functions. The cerebrum controls voluntary actions and processes information from sense organs, cerebellum takes care of balance and coordination, and medulla governs automatic processes like heart rate and breathing.

  • The spinal cord acts as a pathway for nerve impulses to and from the brain and the rest of the body. It also plays a direct role in reflex actions.

  • The eye as a sensory organ demonstrates response and regulation in the nervous system. Light entering the eye triggers nerve impulses that the brain interprets as images. The eye also adapts to different light levels through dilation and constriction of the pupil.

  • Remember that plenty of practise in drawing and labelling diagrams of brain, neuron, and eye can help in understanding the concepts and in remembering the terms.