Central Nervous System

Central Nervous System


  • The Central Nervous System (CNS) includes the brain and spinal cord.
  • It serves as the main processing centre for the entire nervous system, controls most functions of the body and mind.

The Brain

  • Divided into three main parts: cerebrum, cerebellum, and brain stem.
  • The cerebrum controls voluntary actions, speech, senses, thought and memory.
  • The cerebellum manages balance, coordination and muscle movement.
  • The brain stem regulates involuntary activities, like heartbeat, blood pressure and breathing.

The Spinal Cord

  • Connects the brain to the rest of the body and to peripheral nervous system.
  • Allows for two-way communication between the brain and body.
  • Transmits motor information from the brain to the body, and sensory information from the body back to the brain.


  • The brain and spinal cord are made up of specialised cells called neurons.
  • These neurons communicate with other neurons and muscles through electrical signals _nerve impulses_.
  • Each neuron consists of a cell body, dendrites and an axon for impulse transmission.

Synapses and Neurotransmitters

  • Synapses are the tiny gaps that neurons communicate across.
  • Neurotransmitters are chemicals that transmit impulses across synapses from neuron to another.

Central Nervous System Disorders

  • Damage to the CNS can cause serious disorders such as multiple sclerosis, Parkinson’s disease and Alzheimer’s disease.
  • These disorders may impair memory, speech, movement, and other basic bodily functions.

Protection of the Central Nervous System

  • Both the brain and spinal cord are protected.
  • The brain is encased in the skull, while the spinal cord is encased in vertebrae.
  • Additionally, both are surrounded by cerebrospinal fluid which serves as a shock absorber.


  • The Central Nervous System is crucial for human survival and functionality.
  • It receives, processes, and sends out information to and from all parts of the body.

Remember to further explore each section when revising, thoroughly understand the function of each component and the possible effects when the CNS suffers damage.