nervous system

• state two differences between the somatic and autonomic nervous system (PPQ)

  • the autonomic nervous system is involuntary whereas the somatic nervous system is under conscious control.
  • ANS controls smooth muscles and glands whereas the SNS controls skeletal muscles.
• Information can only travel in one direction at a synapse. Explain why neurons can only transmit information in one direction at a synapse. (PPQ)

  • the synaptic vesicles containing the neurotransmitter only present on the presynaptic membrane
  • the receptors for the neurotransmitters are only present on the postsynaptic membrane
  • it is the binding of the neurotransmitter to the receptor which enables the signal to be transmitted
  • Diffusion of the neurotransmitters mean they can only go from high to low concentration, so can only travel from the presynaptic to the postsynaptic membrane.
• describe the function of the spinal cord

  • relays information between the brain and the rest of the body
  • allows the brain to monitor and regulate processes, like digestion and breathing
  • responsible for enabling us to perform simple reflexes without the brain's involvement
• state and describe the different areas of the brain (but not lobes)

  • cerebrum- divided into four different lobes, involved in though and speech production. Split into cerebral hemispheres
  • cerebellum- involved in controlling motor skills and balance, Abnormalities can cause motor problems and epilepsy
  • diencephalon- thalamus and hypothalamus, thalamus- acts as a relay station for nerve impulses- routing them to parts of the brain where they can be processed. Hypothalamus- link between endocrine and nervous system, controls hormone release from the pituitary gland, involved in the fight or flight response
  • brain stem- regulates automatic functions, like breathing, heart rate and swallowing
• state the different subdivisions of the nervous system

  CNS- brain and spinal cord- spina; nerves

  PNS- all nerves outside the CNS

  A) somatic

  B) autonomic

  C) motor

  D) sensory

  E) sympathetic

  F) parasympathetic

  
• what is the function of the SNS?

  • 12 pairs of cranial nerves, 31 pairs of spinal nerves
  • sensory and motor neurones
  • sensory neurones relay info to CNS, motor neurons relay them from the CNS
  • responsible for reflex actions
• what is the function of the autonomic NS?

  • regulates automatic processes that don't require conscious thought- eg breathing and heartbeat
  • split into sympathetic and parasympathetic NS
  • they each have neurotransmitters with opposite effects