Neurons

Question 1

What is a ‘neuron’?

Answer 1

• It is the basic building blocks of the nervous system.
• They are nerve cells that process and transmit messages through electrical and chemical signals.

Question 2

What are the 3 neurons in the spec?

Answer 2

• Sensory
• Relay
• Motor

Question 3

Describe a Sensory Neuron.

Answer 3

• It transmits messages from the PNS to the CNS, specifically from sensory receptors to the spinal cord and brain.
• They have long dendrites and short axons.
• They are found at the surface of the body.
• Cell body is found outside instead of inside on a diagram.

Question 4

Describe a Relay Neuron.

Answer 4

• It allows impulses to be transmitted across sensory and motor neurons to communicate.
• Most common type of neuron in the CNS.
• They are found in the brain, spinal cord, and visual system.
• They have both short axons and short dendrites.

Question 5

Describe a Motor Neuron.

Answer 5

• Carry impulses from the CNS to the PNS, specifically from the spinal cord and brain to the effectors (muscles and glands).
• Their axons are directly or indirectly linked to muscles.
• They have long axons and short dendrites.

Question 6

What is the ‘Cell Body’?

Answer 6

• Known as the factory of the neuron.
• Contains the nucleus and produces all proteins in which the neuron needs to function.

Question 7

What is the ‘Nucleus’?

Answer 7

• Contains the genetic material with the neuron.

Question 8

What are ‘Dendrites’?

Answer 8

• They are branch like features which protrude from the cell body.
• They carry nerve impulses from neighbouring neurons toward the cell body.

Question 9

What is the ‘Axon’?

Answer 9

• This carries the electrical impulse from the cell body and down the length if the neuron.
• It is covered in a myelin sheath.

Question 10

What is the ‘Myelin Sheath’?

Answer 10

• It is a fatty layer
• Protects and surrounds the axon
• Helps to speed up electrical transmission of the impulse

Question 11

What are ‘Nodes of Ranvier’?

Answer 11

• They are gaps in between the myelin sheath
• They speed up the transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon.

Question 12

What are ‘Terminal buttons’?
(Presynaptic terminal)

Answer 12

• These are located at the end if the axon
• They communicate with the next neuron that is on the other side of the synaptic cleft (gap).