The structure and function of neurons Flashcards
1
Q
What are the three types of neurons?
A
- sensory neuron
- relay neuron
- motor neuron
2
Q
cell body
A
- includes nucleus
- nucleus contains genetic material
3
Q
dendrites
A
- branch like structures
- protrude from cell body
- carry nerve impulses from neighboring neurons towards the cell body
4
Q
axon
A
- carries impulses away from cell body down the length of the neuron
5
Q
myelin sheath
A
- fatty layer that covers the axon
- protects axon
- speeds up electrical transmission of the impulse
6
Q
nodes of Ranvier
A
- segments myelin sheath
- speed up transmission of the impulse
- force it to jump across the gaps along the axon
7
Q
terminal buttons
A
- communicate with the next neuron along across a gap known as the synapse
8
Q
sensory neuron
A
- carry messages from the PNS (peripheral nervous system) to the CNS (central nervous system).
- They have long dendrites and short axons
9
Q
relay neurons
A
connect the sensory neurons to the motor or other relay neurons.
- short dendrites and long axons
10
Q
motor neurons
A
- connect the CNS to effectors such as muscles and glands
- they have short dendrites and long axons
11
Q
where are motor neurons located?
A
- cell bodies in the CNS
- long axons in the PNS
12
Q
where are sensory neurons located?
A
- PNS in clusters known as ganglia
13
Q
where are relay neurons located?
A
- make up 97% of neurons
- most found within the brain and visual system
14
Q
how is an electrical impulse caused?
A
- when a neuron is in resting state the inside of the cell is negatively charged compared to the outside
- activation by the stimulus causes the inside to become positively charged for a split second which causes an action potential .
- creates an electrical impulse that travels down the axon towards the end of the neuron
