8.2 - Neural signalling

Question 1

Neurone

Answer 1

Specialised cells that carry electrical impulses

Question 2

Nerve fibres

Answer 2

Also known as axons are long slender projections of neurones that carry electrical impulses away from the cell body

Question 3

Axon

Answer 3

Nerve signals in the form of an action potential travel down the axon to axon terminals

Question 4

Axon Terminal

Answer 4

The end of an axon where the nerve signal, followed by the dendrite of another neurone or an effector

Question 5

Sensory Neuron

Answer 5

Transmit nerve impulses from sense receptors to the central nervous system (CNS)

Question 6

Interneuron

Answer 6

Are located within the central nervous system (CNS) and transmit impulses between neurons

Question 7

Motor Neuron

Answer 7

transmit nerve impulses from the central nervous system (CNS) to an effector

Question 8

Resting Potential

Answer 8

In an axon that is not transmitting an impulse, the inside of the axon always has a negative electrical potential or charge, compared to the outside of the axon which has a positive electrical potential. This membrane potential in a resting neurone is known as resting potential and is typically -70mv in humans

Question 9

Sodium-Potassium Pump

Answer 9

Carrier proteins which are present in the cell surface membranes of neurones, and use ATP to actively transport sodium ions out of the axon and potassium ions in to the axon

Question 10

Nerve Impulse

Answer 10

A momentary reversal in the electrical potential difference across the neurone cell surface membrane. (an action potential)

Question 11

Action Potential

Answer 11

A self-propagating wave of ion movements in and out of the neurone membrane (like dominoes) the action potential is essentially the movement of sodium ions

Question 12

Myelin

Answer 12

A multilayer of phospholipids and proteins which surround axons and acts as an insulating layer

Question 13

Myelinated axons

Answer 13

Axons surrounded by myelin sheaths which have much faster nerve impulse transmission speeds of up to 150m/s^-1

Question 14

Non-myelinated axons

Answer 14

Have a much lower speed of nerve impulse which is 0.5- 10 m/s^-1

Question 15

Synapses

Answer 15

Junctions between two neurones or a neurone and an effector, such as muscles or gland

Question 16

Presynaptic Membrane

Answer 16

The neurone transmitting a signal, releasing neurotransmitters into the synaptic cleft

Question 17

Synaptic Cleft

Answer 17

The gap between the pre and post synaptic membranes

Question 18

Postsynaptic membrane

Answer 18

The neurone receiving the signal, by detecting the presence of neurotransmitters which bind to its receptors

Question 19

Neurotransmitter

Answer 19

chemicals that transmit nerve impulses

Question 20

Acetylcholine

Answer 20

An example of a neurotransmitter that generates an action potential