Neurotransmission

Question 1

Basic Elements of Neurons

Answer 1

• Cell body (soma)
• Dendrites
• Nerve Fiber (axon)
• Axon hillock

Question 2

Axon Hillock

Answer 2

• AKA “trigger zone”
• Where the action potential begins
• Area between axon and soma

Question 3

Afferent Never Fibers

Answer 3

• Afferent = Arriving
• Transmit nerve impulses from periphery to the CNS

Question 4

Efferent Nerve Fibers

Answer 4

• Efferent = Exiting
• Transmit nerve impulses from the CNS to the periphery

Question 5

Classifications of Afferent Nerve Fibers

Answer 5

• A fibers
  1. A alpha
  2. A beta
  3. A gamma
  4. A delta
• B fibers
• C fibers

Question 6

Which Afferent Nerve Fibers Are Myelinated

Answer 6

• A fibers
  1. A alpha
  2. A beta
  3. A gamma
  4. A delta
• B fibers

Question 7

Which Afferent Nerve Fibers Are Not Myelinated

Answer 7

C fibers

Question 8

Myelin

Answer 8

• Produced by schwann cells
• Surround A and B fibers
• Insulator- prevents ion flow across myelin
• Allows for saltatory conduction

Question 9

Nodes of Ranvier

Answer 9

• Spaces between myelin on nerve fibers
• Span 1 - 2 micrometers in length
• Occur every 1 - 2 millimeters on the nerve cell
• Portion of myelinated nerve fibers that allows for ion transfer (between myelinated portions)

Question 10

Saltatory Conduction

Answer 10

• Action potential that jumps from node to node (of ranvier)
• Successive excitation between nodes
• 10x increase in nerve transmission velocity

Question 11

2 Mechanisms of Neuronal Communication

Answer 11

1. Chemical Communication
   * neurotransmitters
2. Electrical Communication
   * active conduction
   * passive conduction

Question 12

Active Electrical Conduction

Answer 12

• Axonal conduction
• Nerve impulse initiated at axon hillock
• Action potential occurs

Question 13

Passive Electrical Conduction

Answer 13

• Dendritic Conduction
• Dendrites recieve information from other neurons or wait for signal to be recieved

Question 13

Passive Electrical Conduction

Answer 13

• Dendritic Conduction
• Dendrites recieve information from other neurons or wait for signal to be recieved

Question 14

What is the Resting Membrane Potential

Answer 14

• Voltage difference across the cell membrane as a result of ion concentration differences at rest
  1. principally the differences between Na and K concentrations
• Typically about -60 to -80 mV (inside cell)