divisions of the nervous system

• The nervous system


  Body wide system of nerve cells that collects information from the world, processes this information and then takes action by directing body organs and muscles via the transmission of electro chemical messages
• Central Nervous system (CNS)


  Contains the brain and the spinal cord.

  The brain: provides conscious awareness and is involved in all psychological processes.

  Spinal Cord: transfers messages to and from the brain and the rest of the body, responsible for simple reflex actions that don't involve the brain.
• Peripheral Nervous System (PNS)


  Body wide network of messenger neurons

  Relays information and messages from the CNS to the rest of the body.

  Made up of the somatic and autonomic nervous system.
• Somatic Nervous system


  Facilitates communication between the CNS and the outside world.

  Made up of sensory receptors and motor pathways.

  Sensory receptors - carry information to the CNS.

  Motor pathways - allow brain to control movement.
• Autonomic Nervous system


  Controls actions of internal organs and glands.

  Only consists of motor pathways.

  Made up of the sympathetic nervous system and parasympathetic nervous system.
• Sympathetic Nervous system (SNS)


  Involved in fight or flight response.

  Impulses travel from the SNS to the organs to help prepare for action when we are faced with a dangerous situation.

  Causes heart rate, blood pressure and breathing rate to increase.
• Parasympathetic nervous system


  Relaxes the body and returns it to normality after the perceived threat has passed (homeostatis)

  Decreases heart rate, blood pressure and breathing rate.
• Homeostasis


  Regulation of the internal environment. In normal conditions there is a balance between sympathetic and parasympathetic systems. This is called maintaining homeostasis.