Nervous system

• The nervous system is split into the Central nervous system (CNS) and the Peripheral nervous system (PNS).
• Central nervous system consists of the brain and the spinal cord:

  • Brain contains all conscious and unconscious processing.
  • Spinal cord receives and transmits information (some reflex processing).
• Peripheral nervous system is a network of messenger neurones.

  • Sensory (afferent) neurones to the CNS.
  • Motor (efferent) neurones away from the CNS.

  Peripheral nervous system contains the autonomic and somatic nervous system.
• Somatic nervous system (SNS) controls skeletal muscles for movement. This voluntary movement (under conscious control).
• Autonomic nervous system (ANS) controls actions of internal organs and glands . This is involuntary movement (not under conscious control).
• ANS is divided into the sympathetic and parasympathetic nervous systems:

  • Sympathetic - Responsible for 'fight or flight'. This increases bodily activities and releases noradrenaline.
  • Parasympathetic - Responsible for 'rest and digest'. This decreases bodily activities and releases acetylcholine.
• Homeostasis is the regulation of the internal environment of the body. In normal conditions there is a balance between the sympathetic and parasympathetic systems. This is how homeostasis is maintained.
• Synaptic transmission is the process of the transmission of information from one neuron to another.