Neurons

Question 1

Define neuron

Answer 1

Nerve cells that process and transmit messages through electrical and chemical signals

Question 2

How many neurons are in the body

Answer 2

100 billion neurons
80% located in the brain

Question 3

What is the size variation of a neuron

Answer 3

<1mm to 1m long

Question 4

What does the Nucleus do

Answer 4

contains genetic material

Question 5

What are Dendrites

Answer 5

Branch like structures protruding from cell body
Carry nerve impulses from neighbouring neurons toward cell body

Question 6

What is the Axon

Answer 6

Carries impulses away from cell body down length of neuron
Covered in fatty layer of myelin sheath

Question 7

What is the Myelin Sheath

Answer 7

Protects the axon
Speeds up electrical transmission of an impulse
Segmented by gaps called Nodes of Ranvier

Question 8

What are the Nodes of Ranvier

Answer 8

Forces the impulse to ‘jump’ across the gaps along the axon

Question 9

What are the Terminal Buttons

Answer 9

At the end of the axon
Communicate with the next neuron in the chain across the synapse

Question 10

Sensory Neuron

Answer 10

Carries messages from PNS to CNS
Long dendrites, Short axon

Question 11

Relay Neuron

Answer 11

Connect sensory neuron to motor neuron or other relay neuron (intermediary)
Short dendrites, Short axon

Question 12

Motor Neuron

Answer 12

Connect CNS to effectors
Short dendrites, Long axon

Question 13

Describe the process of Firing a Neuron

Answer 13

1.Electrical transmission takes place within a neuron
2. When in a resting state, the inside of the cell is negatively charged (outside is not)
3. When a neuron is activated by a stimulus, inside becomes positively charged for a split-second causing an action potential
4. Action potential creates an electrical impulse that travels down the axon to the end of the neuron
5. Signals within the neuron are transmitted electrically
6. Signals between two neurons are transmitted chemically across a synapse