Lecture 2: Structure and Function of a Neuron

Question 1

What are the parts of a neuron?

Answer 1

• Dendrites
• Axon
• Soma

Question 2

What is the role of the dendrites?

Answer 2

They have a large surface area that connects and receives info from other neurons

Question 3

What is the role of the soma?

Answer 3

Cell body and metabolic centre of the cell, with partially permeable membrane and ion channels

Question 4

What is the role of the axon?

Answer 4

Transmits signal to the next neuron, organ or muscle with myelin sheath and nodes of ranvier

Question 5

What is myelination?

Answer 5

Myelin sheath is in rings around the axon to increase speed of conduction, protect axon and insulate

Question 6

What are the different types of neuron?

Answer 6

• Motor
• Sensory
• Relay

Question 7

What is the structure of a sensory neuron?

Answer 7

Single axon, long dendrite, cell body in middle

Question 8

What is the function of a sensory neuron?

Answer 8

Transmit signals from PNS to CNS (spine to brain) afferent

Question 9

What is the structure of a relay neuron?

Answer 9

Short axons, loads of short dendrites

Question 10

What is the function of a relay neuron?

Answer 10

Carries messages along CNS and connects sensory and motor neurons

Question 11

What is the structure of a motor neuron?

Answer 11

Short dendrites and long axons

Question 12

What is the function of a motor neuron?

Answer 12

Carry signals from CNS to organs, muscles or glands

Question 13

What is a glial cell?

Answer 13

Provides physical and chemical support to neurons to maintain environment

Question 14

What is an astrocyte?

Answer 14

Largest glial cell that wraps around blood vessels and cell bodies for protection

Question 15

What is a microglia?

Answer 15

Part of immune system that protects brain

Question 16

What are oligodendrocytes?

Answer 16

Myelinate single axons in CNS

Question 17

What are Schwann cells?

Answer 17

Myelinate single axons in PNS

Question 18

What are radial glia?

Answer 18

Guide growth of axons during embryonic development

Question 19

Describe the process of action potential

Answer 19

1. Neuron is at resting potential (inside the cell is -70mv and more negatively charged than outside)
2. Stimulus is received causing charge to be more positive (-65mv) and sodium channels open (depolarisation)
3. Positive charged sodium ions flow into cell and make inside more positive, exceeding excitation threshold
4. When stimulus passes, potassium ions leave and make inside more negative again going back to resting state (repolarisation)

Question 20

What is the refractory period?

Answer 20

Time following stimulus where nerve is unable to respond to another

Question 21

What is absolute refractory period?

Answer 21

Membrane can’t produce an action potential because sodium channels are inactive

Question 22

What is relative refractory period?

Answer 22

Stronger stimulus needed to trigger AP because potassium channels are still open

Question 23

What is propagation?

Answer 23

How the electrical signal travels along the length of the neuron