Nervous system

• What is the primary purpose of a neuron?

  To communicate electrically and chemically
• How do neurons send and receive information?

  They receive and send information to other cells
• What is a bundle of neurons called?

  A nerve
• How are signals transmitted within neurons?

  Signals are transmitted electrically along the neuron
• How are signals transmitted between neurons?

  Signals are transmitted chemically across the synapse
• What are the branchlike projections that receive signals called?

  Dendrites
• What happens to the signal after it enters through the dendrites?

  It is transferred to the cell body
• What is the pathway of a signal in a neuron?

  The signal travels down the axon to the axon terminal
• What occurs at the axon terminal?

  The signal is chemically transferred across a synapse
• What is the charge of a neuron in its resting state?

  The inside is negatively charged
• What happens when a signal is received by the dendrites?

  The cell temporarily becomes positively charged
• What is an action potential?

  It is the temporary positive charge that travels down the axon
• What are the three types of neurons?

  1. Motor neurons - control movement
  2. Sensory neurons - allow us to feel
  3. Relay neurons - allow motor and sensory to communicate
• What do motor neurons do?

  They transmit messages away from the CNS towards organs and muscles
• What is a characteristic of motor neurons?

  They tend to have long axons and short dendrites
• What do sensory neurons do?

  They pick up sensory information and convert it to electrical signals
• How do sensory neurons carry messages?

  They carry messages towards the CNS from the senses processed by the PNS
• What is a characteristic of sensory neurons?

  They have long dendrites and short axons
• Where is the cell body of sensory neurons usually located?

  In a side branch
• What do relay neurons do?

  They connect other neurons together and allow communication
• What is a characteristic of relay neurons?

  They tend to have short dendrites and short axons
• What is synaptic transmission?

  • Process by which a signal is carried across the synapse
  • Involves neurotransmitters released into the synapse
• How does a nerve impulse travel in synaptic transmission?

  It travels down an axon of a pre-synaptic neuron
• What happens when the nerve impulse reaches the axon terminal?

  It triggers neurotransmitters to move to the edge of the membrane
• What occurs after neurotransmitters are released into the synaptic gap?

  They travel across the synapse
• What happens when neurotransmitters bind to receptors on the post-synaptic neuron?

  It triggers the electrical signal to be sent down the post-synaptic neuron
• What happens to neurotransmitters left in the synapse?

  They are taken back by the pre-synaptic neuron or broken down by enzymes
• What do vesicles in the pre-synaptic neuron do?

  They are refilled with neurotransmitter for the next signal
• How do neurotransmitters affect the post-synaptic neuron?

  They can cause different responses
• What do excitatory neurotransmitters do?

  They increase the positive charge of the neuron
• What is an example of an excitatory neurotransmitter?

  Dopamine
• What do inhibitory neurotransmitters do?

  They increase the negative charge of the neuron
• What is an example of an inhibitory neurotransmitter?

  Serotonin
• What is summation in the context of neurotransmitters?

  It is when different neurotransmitters are released together at the synapse
• What happens if excitatory neurotransmitters outweigh inhibitory ones?

  The post-synaptic neuron will fire
• What happens if inhibitory neurotransmitters outweigh excitatory ones?

  The post-synaptic neuron will not fire
• What are the two main systems of the nervous system?

  The central nervous system (CNS) and the peripheral nervous system (PNS)
• What are the main functions of the central nervous system (CNS)?

  • Control of behaviour
  • Regulation of the body's biological processes
• How does the CNS interact with the rest of the body?

  It receives information from other nervous systems and sends messages to muscles and glands
• What are the two main components of the CNS?

  • The brain
  • The spinal cord