Neurons and Synaptic transmission

• What is the biological structure discussed in the context of biological psychology?

  The synapse
• How does the synapse help in understanding psychoactive drugs?

  It explains how information is passed and how drugs affect brain function
• What is synaptic transmission?

  • The process where information is passed between neurons
  • Involves electrical impulses and chemical neurotransmitters
  • Critical for communication in the nervous system
• What is the gap between two neurons called?

  The synaptic cleft
• What is the size of the synaptic cleft?

  About 20 to 40 nanometers
• What are the chemicals called that transmit signals across the synapse?

  Neurotransmitters
• What happens when an action potential reaches the axon terminal?

  It causes vesicles to merge with the presynaptic membrane
• What is the role of receptors on the postsynaptic neuron?

  They detect the presence of neurotransmitters
• What is summation in the context of synaptic transmission?

  It is the process of adding excitatory and inhibitory signals
• What occurs during depolarization in the postsynaptic neuron?

  Positively charged sodium ions enter the cell
• What effect do excitatory neurotransmitters have on the postsynaptic neuron?

  They make the electrical charge more positive
• What happens when inhibitory neurotransmitters are detected by receptors?

  They hyperpolarize the postsynaptic neuron
• What is the typical firing rate of a neuron?

  Between 5 and 50 times a second
• What is the function of reuptake in synaptic transmission?

  It recycles neurotransmitters back into the presynaptic cell
• What do SSRIs do in the treatment of depression?

  They block the reabsorption of serotonin
• How does cocaine affect neurotransmitter transmission?

  It blocks the reabsorption of dopamine
• What is the significance of synapses in the brain's function?

  • They enable communication between neurons
  • They are fundamental to consciousness, memories, and experiences
  • They illustrate the complexity of brain function
• How many neurons are estimated to be in the human brain?

  About 100 billion neurons
• How many synaptic connections can a single neuron have?

  As many as 15,000 synaptic connections
• How many synapses does an average 20-year-old male have?

  About 170 trillion synapses
• What is the structure called that neurons form to enable quick reactions to pain?

  Reflex arc
• What are the three types of neurons involved in a reflex arc?

  Sensory neuron, relay neuron, and motor neuron
• What is the function of the sensory neuron in the reflex arc?

  To detect sensations
• Where is the relay neuron located in the reflex arc?

  In the spine
• What is the role of the motor neuron in the reflex arc?

  To activate the effector
• What are the main components of a neuron?

  • Cell body (contains nucleus)
  • Axon
  • Dendrites
  • Axon terminals
• What is the function of the myelin sheath on axons?

  To protect the cell and increase the speed of transmission
• What is the structure called where the axon terminals almost touch the dendrites of the next neuron?

  Synapse
• How does information travel along a neuron?

  It travels from dendrites to axon and then to axon terminals
• What happens when an electrical signal reaches the axon terminal?

  It converts into a chemical signal
• What is the role of the central nervous system in reflex actions?

  To process information sent from the relay neuron
• What is proprioception?


  A sense that informs the body of its position in space
• What is the speed of the fastest neuron in the body?

  119 meters per second
• How fast does the alpha motor neuron transmit information?

  At 119 meters per second or 266 miles per hour
• What is the speed of type C neurons that transmit pain?

  One mile per hour
• Why are type C neurons slower than other neurons?

  Because they are often smaller and unmyelinated
• What are the steps involved in the reflex arc process?

  1. Sensation detected by sensory receptors
  2. Electrical signal travels along dendrite to axon
  3. Signal converts to chemical at axon terminal
  4. Chemical signal crosses synapse to relay neuron
  5. Relay neuron sends signal to motor neuron
  6. Motor neuron activates effector (muscle fiber)
• What are the characteristics of the fastest and slowest neurons?

  • Fastest: Alpha motor neuron, 119 m/s (266 mph)
  • Slowest: Type C neurons, 1 mph, smaller and unmyelinated