U7 Physiology

Question 1

What is the basic functional unit of the nervous system?

Answer 1

The neurone.

Question 2

What is the role of dendritic spines?

Answer 2

They increase the surface area for synapses.

Question 3

What is the function of the cell membrane in a neurone?

Answer 3

Separates the inside of the cell from the exterior environment and controls ion flow.

Question 4

How are nerve impulses regenerated?

Answer 4

They are regenerated at each point along the axon to maintain strength.

Question 5

What are ions?

Answer 5

Electrically charged particles formed when electrolytes dissolve in water.

Question 6

What is the resting potential of a neurone?

Answer 6

Approximately -70 millivolts.

Question 7

What are the two main forces acting on ions in a neurone?

Answer 7

Electrostatic pressure and diffusion.

Question 8

What maintains the resting potential of a neurone?

Answer 8

Sodium-potassium pumps.

Question 9

What happens during depolarisation?

Answer 9

The membrane potential becomes more positive.

Question 10

What is the ‘threshold of excitation’?

Answer 10

The voltage needed to trigger an action potential.

Question 11

What is the all-or-none law?

Answer 11

A neurone either fires completely or does not fire at all.

Question 12

What causes repolarisation in a neurone?

Answer 12

Efflux of potassium (K+) ions out of the cell.

Question 13

What is hyperpolarisation?

Answer 13

When the membrane potential becomes more negative than the resting potential.

Question 14

What is the refractory period?

Answer 14

The period during which a neurone cannot or is less likely to fire again.

Question 15

What is action potential propagation?

Answer 15

The movement of the action potential along the axon.

Question 16

What role do myelin sheaths play in action potentials?

Answer 16

They insulate axons and increase conduction efficiency.

Question 17

What is saltatory conduction?

Answer 17

Action potentials jumping from one node of Ranvier to the next.

Question 18

What causes multiple sclerosis?

Answer 18

The immune system attacks myelin sheaths, disrupting nerve conduction.

Question 19

What is a synapse?

Answer 19

The gap between neurones where communication occurs.

Question 20

What is an EPSP?

Answer 20

Excitatory postsynaptic potential caused by depolarisation.

Question 21

What is an IPSP?

Answer 21

Inhibitory postsynaptic potential caused by hyperpolarisation.

Question 22

What is temporal summation?

Answer 22

The additive effect of multiple EPSPs in rapid succession.

Question 23

What is spatial summation?

Answer 23

The additive effect of EPSPs from multiple presynaptic neurones.

Question 24

What did Loewi’s 1920 experiment demonstrate?

Answer 24

Neurotransmitters communicate messages between neurones.

Question 25

How are neurotransmitters removed from the synapse?

Answer 25

Through breakdown by enzymes or reuptake by the presynaptic neurone.

Question 26

What enzyme breaks down acetylcholine?

Answer 26

Acetylcholinesterase.

Question 27

What is reuptake?

Answer 27

The process by which neurotransmitters are reabsorbed into the presynaptic neurone.

Question 28

What are autoreceptors?

Answer 28

Presynaptic receptors that regulate neurotransmitter release.

Question 29

What is the role of nitric oxide in neurotransmission?

Answer 29

Provides negative feedback to inhibit neurotransmitter release.

Question 30

What is the role of calcium (Ca2+) in synaptic transmission?

Answer 30

Triggers neurotransmitter release from the presynaptic terminal.