Neurons and Action Potential - Topic 1

Question 1

What are neurons?

Answer 1

Neurons are the basic cells of the nervous system, and are fundamental in the operation of homeostasis

Question 2

What 2 key components are within the nerve impulse?

Answer 2

1. Action Potential (conduction with a neuron)
2. Synaptic Transmission (communication between neurons)

Question 3

What is the role of Dendrites?

Answer 3

Receive synaptic input from axons
With the sum total of dendritic inputs determining whether the neuron will fire an action potential

Question 4

What is the role of Soma?

Answer 4

It is located where the nucleus lies and is where the neuron’s DNA is housed
Where proteins are made to be transported throughout the axon and dendrites

Question 5

What is the role of the body in a neuron?

Answer 5

Contains genetic information
Maintains the neuron’s structure
and provides energy to drive activities

Question 6

What is the role of the Axon?

Answer 6

The axon is a thin fiber that connects neurons (nerve cells) so that they can communicate

Question 7

What is the role of the myelin sheath?

Answer 7

Allows electrical impulses to transmit quickly and efficiently along the nerve cells
If the myelin become damaged these impulses slow down

Question 8

What is the role of the nodes of Ranvier?

Answer 8

These are gaps in the myelin sheath coating on the neural axon
The nodes of Ranvier allow for ions to diffuse in and out of the neuron, propagating the electrical signal down the axon

Question 9

What is the role of the axon terminal?

Answer 9

The axon terminal is the site of neurotransmitter release

Question 10

What is the role of the synapse?

Answer 10

Synapses connect neurons and help transmit information from one neuron to the next

Question 11

What are sensory neurons?

Answer 11

Sensory neurons transmit information from sensory receptors to the central nervous system (CNS)

Question 12

What are relay neurons?

Answer 12

Relay neurons (interneurons) transmit information within the CNS as part of the decision-making process

Question 13

What are motor neurons?

Answer 13

Motor neurons transmit information form the CNS to effectors (muscles of glands), in order to initiate a response

Question 14

Difference of dendrite between sensory and motor neurons?

Answer 14

Sensory - Longer and receive sensory input from the environment
Motor - Shorter and receive signals from the CNS or interneurons.

Question 15

Difference of soma between sensory and motor neurons?

Answer 15

Sensory - located in the dorsal root ganglion of the spinal cord
Motor - located in the ventral horn of the spinal cord

Question 16

Difference of body between sensory and motor neurons?

Answer 16

Sensory - located outside the CNS
Motor - located inside the CNS

Question 17

Difference of axon between sensory and motor neurons?

Answer 17

Sensory - long axon that transmits sensory information to the CNS
Motor - long axon that transmits motor commands to effector organs

Question 18

Difference of myelin sheath between sensory and motor neurons?

Answer 18

Sensory - produced by Schwann cells in the PNS
Motor - produced by oligodendrocytes in the CNS or Schwann cells PNS

Question 19

Difference of nodes of ranvier between sensory and motor neurons?

Answer 19

Both allow for saltatory conduction

Question 20

Difference of axon terminal between sensory and motor neurons?

Answer 20

Sensory - synapses with interneurons in the CNS
Motor - synapses with effector organs at neuromuscular junctions

Question 21

Difference of synapses between sensory and motor neurons?

Answer 21

Sensory - transmits signals to interneurons or directly to motor neurons
Motor - transmits signals to muscles or glands to elicit a response

Question 22

What is the pre-synaptic cell?

Answer 22

The neuron that has just undergone action potential to pass on a signal toward a synapse

Question 23

What is the post-synaptic cell?

Answer 23

The cell receiving information from another neuron and transmits signals away from a synapse

Question 24

What is a synaptic cleft/terminal?

Answer 24

An area at the end of the axon, where a neuron releases neuron transmitters

Question 25

What is a neurotransmitter?

Answer 25

A chemical messenger which allows neuron communication

Question 26

Explain the process of the passage of a nerve impulse

Answer 26

An action potential travels along the neuron’s axon, triggering neurotransmitter release from vesicles in the pre-synaptic neuron. These cross the synaptic cleft, bind to receptor on the post-synaptic neuron, initiating a new action potential via signal transduction