The Nervous System

• what is the nervous system functions?

  -collect, process and respond to environmental information

  -co-ordinate different organs and cells in the body
• what is the central nervous system?

  origin of all complex commands and decisions
• what is the spinal cord?


  is responsible for reflex actions
• what is the brain?

  centre of all conscious awareness, is divided into 2 hemispheres
• what is the peripheral nervous system?

  transmits messages to and from the central nervous system
• what is the somatic nervous system?

  controls voluntary muscle movement and receives information from sensory receptors
• what is the autonomic nervous system?

  controls breathing, heart rate, digestion, sexual arousal and stress responses
• what is the parasympathetic nervous system?

  calms the body down and returns it to a resting state
• what is the sympathetic nervous system?

  gets the body ready for action - the fight or flight system
• what does the thyroid gland do?

  releases thyroxine -- heart rate and metabolism
• what does the pituitary gland do?

  releases all other hormones
• what does the adrenal gland do?

  releases adrenaline + noradrenaline -- fight or flight
• what is the fight or flight response?

  -hypothalamus recognises there is a threat

  -activates sympathetic nervous system

  -message to adrenal glands-release of adrenaline and noradrenaline

  -body response (fight, flight, freeze)

  -once threat decreases, activates parasympathetic nervous system which reverses all changes
• what are the types of neurones?

  -motor neurone -- connects CNS to muscles and glands

  -relay neurone -- relay between sensory and motor neurone (all in CNS)

  -sensory neurone -- from senses to CNS
• what is the process of synaptic transmission?

  -electrical impulses (action potentials) reach the presynaptic ending

  -electrical impulses (action potentials) trigger the release of neurotransmitters e.g serotonin

  -neurotransmitters are released from the vesicles across the synapse

  -neurotransmitters bind with receptors on the postsynaptic membrane

  -stimulation of postsynaptic receptors by neurotransmitters result in either excitation or inhibition on postsynaptic neurone