structure and role of the neuron

Question 1

describe the cell body

Answer 1

• where nucleus sits
• also contains mitochondia

Question 2

describe the nucleus

Answer 2

• house genetic material for that particular neuron

Question 3

describe the mitochondria

Answer 3

• site of aerobic respiration
• energy is released from glucose

Question 4

describe dendrites

Answer 4

• branches at top end of neuron
• receive messages from other neurons

Question 5

describe the axon

Answer 5

• long branch from cell body
• passes electrical impulses down to end of neuron to allow it to communicate with others

Question 6

describe the axon hillock

Answer 6

• area that connects cell body to axon

Question 7

describe the myelin sheath

Answer 7

• fatty deposit
• provides electrical insulation for an axon
• allows electrical nerve impulses to pass along

Question 8

describe the node of ranvier

Answer 8

• gaps between adjacent myelin sheaths

Question 9

describe axon terminals

Answer 9

• end of the axon
• leads to terminal buttons

Question 10

describe terminal buttons/terminal boutons

Answer 10

• very end of neuron
• nerve impulse becomes a chemical message that can be passed to the dendrite of **another neuron

Question 11

describe vesicles

Answer 11

• tiny sacs
• contain molecules of neurotransmitter chemicals

Question 12

describe neurotransmitters

Answer 12

• chemicals
• pass messages between neurons

Question 13

what is action potential?

Answer 13

• method by which nerve impulse passes down axon of the neuron to stimulate the release of neurotransmitters
• tiny electrical impulse that’s triggered by change in the electrical ‘potential’ of neuron itself

Question 14

describe the process of action potential

Answer 14

• neurons have resting membrane potential of about -70mV
• means that the inside of neuron has slight negative charge in relation to outside of neuron
• when neuron receives a message from another neuron, this chemical message can either stimulate an excitatory postsynaptic potential (slightly depolarise neuron, reducing charge), or can hyperpolarise neuron (increasing its charge + stimulating inhibitory postsynaptic potential)

Question 15

what happens when a neuron receives enough excitatory messages?

Answer 15

• if they are sufficiently strong to reach the neuron’s own threshold, an action potential is triggered
• usually happens when neuron’s charge reaches approx -55mV
• action potential sends impulse along the axon of neuron towards axon terminals at the end of neuron