the nervous system

• The nervous system is a specialised network of cells in the human body and is its primary internal communication system.
• The nervous system is divided into two parts: the central nervous system (CNS) and the peripheral nervous system (PNS)
• The CNS is made up of the brain and spinal cord
• The brain is the centre of all conscious awareness and the cerebral cortex, the brain's outer layer, is highly developed in humans. The brain is divided into two hemispheres
• The spinal cord is an extension of the brain and is responsible for reflex actions. It passes messages to and from the brain and connects nerves to the PNS
• The PNS transmits messages, via millions of neurons (nerve cells) to and from the CNS
• The PNS is further divided into the autonomic nervous system and the somatic nervous system
• The autonomic nervous system governs involuntary functions such as breathing, heart rate and stress responses. This is also divided into sympathetic and parasympathetic
• the sympathetic is involved in fight or flight
• the parasympathetic is known as 'rest and digest'. it slows down our heart rate and breathing rate
• The somatic nervous system controls voluntary muscle movement and sensory and motor nerves