The nervous system

• the nervous system

  It is made up of a network of specialised cells, known as neurons. These neurons collect, process and respond to information in the environment through the control of organs and muscles.
• Functions of the nervous system - sensory neurons

  Sensory neurons collect information from sensory organs (e.g. the skin) and carry this message to relay neurons.
• Functions of the nervous system - relay neurons

  Relay neurons in the brain analyse the sensory message and decide how to respond before passing the message to motor neurons.
• Functions of the nervous system - Motor neurons and reflex response

  Motor neurons then connect with skeletal muscles to allow for a physical response. Because these neurons transmit electrical impulses, the nervous system can be used for when behaviours need completing quickly e.g. a reflex response.
• The role of the central nervous system and the brain

  The central nervous system comprises the brain and spinal cord. The brain plays a role in psychological processes such as visual and auditory perception. The brain also plays a role in higher mental functions such as decision making and language.
• The role of the central nervous system - spinal cord

  The spinal cord transmits information to and from the brain. This allows the brain to monitor and regulate bodily processes such as breathing and voluntary movement. The spinal cord also controls reflex responses
• The peripheral nervous system

  The peripheral nervous system refers to the nerves outside the brain and spinal cord. It is divided into two major divisions: the autonomic and somatic divisions.
• The autonomic divisions

  The autonomic division is responsible for unconscious and involuntary life-maintaining processes such as heart rate through the control of internal organs. It therefore comprises of motor neurons and carries commands from the brain stem.
• The Somatic division

  The somatic division is responsible for detecting sensory information and for carrying out conscious, voluntary movements through the control of skeletal muscles. It therefore comprises of sensory and motor neurons and carries commands from the motor cortex in the brain.
• Two similarities between autonomic and somatic NS

  The autonomic and somatic nervous systems are both a part of the peripheral nervous system. This is because they are both made up of the nerves outside the brain and spinal cord.The autonomic and somatic nervous systems both involve motor neurons. This is because the autonomic division relies on motor neurons to carry out involuntary processes such as regulating heart rate and breathing while the somatic division relies on motor neurons to carry out voluntary motor movements.
• 2 differences between the somatic and autonomic divisions of the NS

  The autonomic division is responsible for unconscious, involuntary processes such as heart rate, breathing and digestion - the somatic division is responsible for conscious, voluntary movement. The autonomic division comprises purely of motor neurons as it is only involved in regulating the working of internal organs - the somatic division comprises of sensory and motor neurons as it is involved in detecting sensory information as well as controlling motor movements.
• Difference in the autonomic and somatic divisions - carry commands from

  The autonomic and somatic divisions differ in terms of where they carry commands from. This is because the autonomic division carries commands from the brain stem while the somatic division carries commands from the motor cortex.