Transmission Within/between Neurons

Question 1

What are glia?

Answer 1

Supporting cells to the neuron

Question 2

What are the 3 types of glia?

Answer 2

• Astrocytes: Provide structural support to neurons and Provide nutrients to neuron and they Surround the synapse to help the dispersion of neurotransmitters.
• Oligodendrocytes: Produce the myelin sheath that insulates the axon.
• Microglia: clear away dead neurons

Question 3

What is meant by membrane potential?

Answer 3

The difference between the electrical potential inside and outside the cell.

Question 4

What is meant by action potential?

Answer 4

The reversal in the potential and is the process of how info is sent through the axon.

Question 5

What is meant by depolarisation?

Answer 5

The decrease from normal resting potential - brings it closer to 0

Question 6

What is meant by hyperpolarisation

Answer 6

Increase relative to resting potential

Question 7

Describe the process of action potential

Answer 7

1. Threshold of excitation is reached.
2. This opens up the sodium channel allowing sodium ions to pass through to the cell which causes depolarisation.
3. The potassium channels begin to open and so potassium ions begin to leave the cell.
4. Sodium channels close, potassium channels remain open and ions continue to leave via diffusion.
5. Potassium channels close causing hyper polarisation

Question 8

Describe the process of action potential between neurones

Answer 8

Action potential arrives at the terminal buttons. The calcium channels then open, allowing the flow of calcium ions via diffusion.
The docked vesicle fuses with the membrane so the pore opens and widens. The neurotransmitter is then released and crosses the synaptic cleft via diffusion to the post-synaptic neuron. The neurotransmitter then binds to receptors on the post-synaptic membrane which either opens or closes the channels. When The channels are open they permit the flow of ions which changes the polarisation of the membrane either having an excitatory or inhibitory effect.

Question 9

What are the 2 types of receptors?

Answer 9

• Ionotropic receptors: contain a binding site and ion channel which opens when molecule is attached
• Metabotropic receptors: Contains a binding site. Initiates a chain reaction that eventually opens up channels but requires energy.

Question 10

How are neurotransmitters broken down?

Answer 10

• Reuptake: The transmitter is taken back to the presynaptic terminal via transporter molecules.
• Enzyme deactivation/degradation: The transmitter is broken down by an enzyme.

Question 11

What is neural integration?

Answer 11

• The summation of PSP in control of neural firing.

This can be either excitatory or inhibitory. When there is more excitatory psp the neuron will fire where as when there are more inhibitory psp it will not fire.