Biopsychology - The structure and function of neurons

Question 1

define neuron

Answer 1

The basic building blocks of the nervous system, neurons are nerve cells that process and transmit messages through electrical and chemical signals

Question 2

describe the function of a sensory neuron

Answer 2

They carry messages from the PNS to the CNS.

Question 3

Describe the function of a relay neuron

Answer 3

These connect the sensory neurons to the motor neurons.

Question 4

desccribe the function of a motor neuron

Answer 4

These connect the CNS to effectors such as muscles and glands.

Question 5

What are the 3 types of neurons

Answer 5

sensory, relay and motor

Question 6

describe the structure of a sensory neuron

Answer 6

They have long dendrites and short axons and they are unipolar

Question 7

describe the structure of a relay neuron

Answer 7

They have short dendrites and short axons and they are multipolar

Question 8

describe the structure of a motor neuron

Answer 8

They have short dendrites and long axons and they are multipolar

Question 9

Outline the components of neurons

Answer 9

• The cell body includes a nucleus (all).
• Branch like structures call dendrites protrude from the cell body in multiple directions. (relay and motor)
• The axon carries the impulse away from the cell body down the length of the neuron. The axon is covered in a fatty layer of myelin sheath that protects it and speeds up electrical transmitting of the impulses. The myelin sheath is segmented by gaps called the nodes of Ranvier to allow this. (sensory and motor)
  At the end of the axon are terminal buttons that communicate with the next neuron in the chain across a gap known as the synapse. (all)

Sensory neurons have their dendrites prodruding at the end of their axons rather than the cell body.
Relay neurons do not have myelin sheaths as its role is to speed up transmittions but this is not nessasary on a short neuron like the relay neuron.

Question 10

define soma

Answer 10

cell body of a neuron

Question 11

list the key terms for the structure of a neuron

Answer 11

• cell body
• nucleus
• genetic
• dendrites
• axon
• myelin sheath
• nodes of Ranvier
• terminal buttons
• synapse

Question 12

describe the location of the sensory neurons

Answer 12

They are located outside of the CNS, in the PNS in clusters known as ganglia

Question 13

define action potential

Answer 13

When a neuron is activated by a stimulus, the neuron fires and creates and electrical impulse

Question 14

describe the location of motor neurons

Answer 14

The cell bodies of motor neurons are in the CNS but they have long axons which form part of the PNS

Question 15

describe the location of relay neurons

Answer 15

Relay neurons make up 97% of all neurons and most are found within the brain and the visual system

Question 16

Explain electrical transmission

Answer 16

Electrical transmission is the firing of a neuron.
When a neuron is in a resting state the inside of the cell is negatively charged compare to the outside. When the neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second causing an action potential to occur. This creates an electrical impulse that travels down the axon towards the end of the neuron.