NS & Neurons

• What is the Central Nervous System (CNS)?

  - Consists of the brain and spinal cord

  - Controls behaviour and regulates body's physiological processes

  - Brain receives info from sensory receptors, and sends messages to muscles and glands via spinal cord
• What is the role of the Spinal Cord in the CNS?

  - Relay info between brain and rest of body

  - If damaged, areas supplied by those nerves will stop functioning
• What is the role of the Brain in the CNS?

  - Divided into 4: 2 parts are

  ○ Cerebrum, largest part of brain, split into 4 lobes (frontal, temporal, occipital and parietal), also split into 2 hemispheres which communicate through corpus callosum

  ○ Cerebellum, involved in controlling motor skills, balance etc
• What is the Peripheral Nervous System?

  - All the nerves outside the CNS

  - Functions to relay nerve impulses from CNS to rest of body

  - Divided into somatic and autonomic nervous system
• What is the Somatic Nervous System?

  - Divison responsible for carrying sensory and motor information to and from the CNS

  - Have sensory and motor neurone

  - Involved in reflex actions w/out CNS involvement (quick reflexes)
• What is the Autonomic Nervous System?

  - Regulates involuntary actions e.g. heartbeat and digestion

  Has 2 parts:

  ○ Sympathetic Nervous System: fight or flight response

  ○ Parasympathetic Nervous System: equilibrium
• What are Neurons?

  - Specialised cells that carry neural information

  - Consist of cell body, dendrites and axon

  - Dendrites receive signals from one end of neurone, impulse carried through cell body and axon terminates at axon terminal

  
• What is the role of the Sensory Neuron?

  - Carries nerve impulse from sensory receptor (e.g. vision, taste, smell) to CNS

  - Some will terminate in spinal cord (won't reach brain) allowing quicker reflexes
• What is the role of the Relay Neuron?

  - Lies between sensory input and motor output

  - Allow sensory and motor neurone to communicate

  - Only in brain and spinal cord
• What is the role of the Motor Neuron?

  - Located in CNS, project axons outside to control muscles

  - Form synapses w/muscles and control contractions

  - Strength of contraction dependent on rate of firing of axons
• What is Synaptic Transmission?

  - Process by which nerve impulse passes across synaptic gap from presynaptic neuron to postsynaptic neuron

  - Passed down axon as an electrical impulse known as axon potential

  - Impulse reaches end of axon which has synaptic vesicles containing neurotransmitters that allow transfer of impulse
• What are Excitatory and Inhibitory Neurotransmitters?

  - An excitatory transmitter generates a signal called an action potential in the receiving neuron. An inhibitory transmitter prevents it.