Nerve impulses and synapses Quiz
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5 questions, one answer each
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1. Which ions enter the axon during depolarisation?
- A. K⁺
- B. Cl⁻
- C. Ca²⁺
- D. Na⁺
2. What is the function of the nodes of Ranvier?
- A. They are where action potentials occur in a myelinated axon
- B. They make myelin
- C. They store acetylcholine
- D. They pump Na⁺ in
3. A neurone has a resting potential of −70 mV and a threshold of −55 mV. Each EPSP is 5 mV. How many simultaneous EPSPs are needed to reach threshold?
- A. 2
- B. 3
- C. 15
- D. 11
4. Which event comes immediately after Ca²⁺ entry into the presynaptic knob?
- A. Acetylcholine binds to receptors
- B. Na⁺ channels open in the postsynaptic membrane
- C. Vesicles fuse with the presynaptic membrane
- D. Acetylcholinesterase hydrolyses acetylcholine
5. What effect does an inhibitory postsynaptic potential have?
- A. It depolarises the membrane
- B. It makes the membrane more negative, so threshold is harder to reach
- C. It opens voltage-gated Na⁺ channels
- D. It stops the pump working