Nervous system

• The nervous system is a specialised network of cells in the human body and is or primary internal system. Consists of the central nervous system and the peripheral nervous system. communicates using electrical signals.
• The nervous system has 2 main functions:

  • To collect, process and respond to information in the environment
  • To coordinate the working of different organs and cells in the body.
• the autonomic nervous system regulates involuntary actions such as heart rate, breathing and digestion. Further subdivided into the sympathetic and parasympathetic nervous system.
• the spinal cord runs from the base of the brain to the lower back and carries messages between the brain and other parts of the body
• Th central nervous system (CNS) is made up out of the brain and spinal cord
• the cerebellum coordinates muscle activity and maintains balance and posture
• The peripheral nervous system (PNS) transmits messages via millions of neurons to and from the CNS. It is further subdivided into the autonomic and somatic nervous system
• Somatic nervous system controls voluntary movements and senses information about the environment through sensory receptors
• The sympathetic nervous system is typically involved in responses that prepare the body for fight or flight. Impulses travel from the sympathetic nervous system to organs in the body to help us prepare for action when we are faced with a dangerous situation. For example, our heart rate, blood pressure and breathing rate increase, while less important functions such as digestion, salivation and urination.
• The parasympathetic nervous system relaxes the body, and return us to our ‘normal’ resting state. Slows down our heart rate and breathing rate, and reduces our blood pressure. Any functions that were previously slowed down during a fight or flight reaction are started again (e.g. digestion).
• Functions of the nervous system

  1. to collect, process and respond to information in the environment
  2. to co-ordinate the working of different organs ad cells in the body
• CNS

  •Brain – centre of all conscious awareness and is subdivided into 4 lobes (frontal lobe, parietal lobe, occipital lobe and the temporal lobe). Cerebral cortex is highly developed in humans, which separates our higher mental functions from animals

  •Spinal cord – extension of the brain, responsible for reflex actions

  CNS passes messages to and from the brain and connects nerves to the peripheral nervous system