Biopsychology: NEURONS

• How many nerve cells are in the human body?

  100 billion nerve cells
• What percentage of nerve cells are located in the brain?

  80%
• How are signals transmitted in neurons?

  Electrically and chemically
• What are the three types of neurons?

  1. Motor neurons
  2. Sensory neurons
  3. Relay neurons
• What is the function of motor neurons?

  Connect CNS to effectors like muscles
• What is the structure of motor neurons?

  Small dendrites and long axons
• What do sensory neurons do?

  Carry messages from PNS to CNS
• What is the structure of sensory neurons?

  Long dendrites and short axons
• What is the role of relay neurons?

  Connect sensory neurons to motor neurons
• What is the structure of relay neurons?

  Short dendrites and short axons
• What are the main components of a neuron?

  • Cell body (soma)
  • Dendrites
  • Axon
  • Myelin sheath
  • Terminal buttons
• What is the function of the cell body (soma) in a neuron?

  Contains the nucleus with genetic material
• What do dendrites do in a neuron?

  Carry nerve impulses towards the cell body
• What is the role of the axon?

  Carries electrical impulses away from the cell body
• What is the myelin sheath?

  A fatty layer that protects the axon
• What is the synapse?

  The gap between neurons for communication
• What do terminal buttons do?

  Communicate with the next neuron across the synapse
• What happens when a neuron is activated?

  The inside becomes positively charged
• What is an action potential?

  Electrical impulse created during neuron activation
• What occurs at the end of the axon during activation?

  Electrical impulse travels down the axon
• What is the process of electrical transmission in neurons?

  1. Neuron is at rest, inside is negatively charged.
  2. Activation causes inside to become positively charged.
  3. Action potential occurs, creating an electrical impulse.
  4. Impulse travels down the axon to the terminal buttons.
• What is excitation

  when postsynaptic neurons are more likely to fire an impulse
• What is inhibition

  when postsynaptic neurons are less likely to fire an impulse
• can neurotransmitters be either inhibitory or exictatory?

  yes