Questions About the Neuron and Nerve Impulse
Multiple-Choice Questions: Neuron and Nerve Impulse
1. What is the basic structural and functional unit of the nervous system?
A) Glial cell
B) Neuron
C) Axon
D) Synapse
E) Brainstem
2. Which part of the neuron receives incoming signals from other neurons?
A) Axon
B) Synapse
C) Soma
D) Dendrites
E) Myelin sheath
3. What is the function of the axon?
A) To process information
B) To receive chemical signals
C) To transmit impulses away from the cell body
D) To support the neuron structurally
E) To insulate the nerve cell
4. The myelin sheath primarily functions to:
A) Generate impulses
B) Slow down nerve signals
C) Nourish the axon
D) Speed up nerve impulse conduction
E) Create neurotransmitters
5. What is the gap between two neurons called?
A) Dendrite
B) Synaptic cleft
C) Axon hillock
D) Node of Ranvier
E) Glial gap
6. Which of the following cells form the myelin sheath in the central nervous system?
A) Schwann cells
B) Astrocytes
C) Oligodendrocytes
D) Microglia
E) Ependymal cells
7. In a resting neuron, the inside of the cell is:
A) Positively charged compared to the outside
B) Neutrally charged
C) Negatively charged compared to the outside
D) Positively charged with equal sodium and potassium
E) Only positive in the axon terminals
8. The resting membrane potential of a neuron is approximately:
A) +30 mV
B) 0 mV
C) –70 mV
D) –30 mV
E) +70 mV
9. Which ion enters the neuron during the depolarization phase of the action potential?
A) Potassium (K⁺)
B) Calcium (Ca²⁺)
C) Chloride (Cl⁻)
D) Sodium (Na⁺)
E) Magnesium (Mg²⁺)
10. What causes repolarization of the neuron membrane?
A) Sodium ions entering
B) Chloride ions leaving
C) Potassium ions leaving
D) Calcium ions entering
E) Magnesium ions blocking channels
11. What occurs at the axon terminals during synaptic transmission?
A) The cell body divides
B) Neurotransmitters are released
C) DNA replication occurs
D) Protein synthesis increases
E) Ions stop flowing
12. Which neurotransmitter is most associated with muscle contraction?
A) Dopamine
B) Acetylcholine
C) Serotonin
D) Epinephrine
E) GABA
13. A nerve impulse travels in which direction?
A) Dendrite → Synapse → Axon → Soma
B) Soma → Dendrite → Axon → Synapse
C) Axon → Soma → Synapse → Dendrite
D) Dendrite → Soma → Axon → Synapse
E) Synapse → Axon → Soma → Dendrite
14. The Node of Ranvier is:
A) A cell type that creates myelin
B) The gap in the myelin sheath
C) The place where neurotransmitters are made
D) A part of the synaptic terminal
E) The location of the neuron's nucleus
15. Which ion is primarily responsible for the resting potential of a neuron?
A) Chloride (Cl⁻)
B) Calcium (Ca²⁺)
C) Sodium (Na⁺)
D) Potassium (K⁺)
E) Magnesium (Mg²⁺)
16. What is a synapse?
A) A part of the brain
B) A bundle of axons
C) A connection point between neurons
D) A receptor for neurotransmitters
E) A muscle fiber
17. Which type of glial cell helps form the blood-brain barrier?
A) Schwann cells
B) Oligodendrocytes
C) Astrocytes
D) Microglia
E) Ependymal cells
18. Saltatory conduction refers to:
A) The slow diffusion of neurotransmitters
B) The destruction of axons
C) The jumping of action potentials between nodes
D) The swelling of dendrites
E) The absorption of potassium ions
19. Which ion is essential for neurotransmitter release at the synapse?
A) Sodium (Na⁺)
B) Potassium (K⁺)
C) Chloride (Cl⁻)
D) Calcium (Ca²⁺)
E) Hydrogen (H⁺)
20. What occurs during the refractory period of a neuron?
A) The neuron fires multiple impulses
B) The neuron rests and cannot fire another impulse
C) Sodium channels open
D) Neurotransmitters are absorbed
E) Myelin is removed
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Answer Key with Explanations
1. B) Neuron – The functional unit that conducts electrical impulses.
2. D) Dendrites – Receive signals from other neurons.
3. C) To transmit impulses away from the cell body – The axon conducts action potentials.
4. D) Speed up nerve impulse conduction – Myelin increases signal velocity.
5. B) Synaptic cleft – The tiny gap between two communicating neurons.
6. C) Oligodendrocytes – Myelinate axons in the CNS.
7. C) Negatively charged compared to the outside – The resting potential is negative inside.
8. C) –70 mV – Typical resting potential of neurons.
9. D) Sodium (Na⁺) – Flows into the neuron, causing depolarization.
10. C) Potassium ions leaving – Repolarization happens as K⁺ exits the cell.
11. B) Neurotransmitters are released – This allows communication with the next neuron.
12. B) Acetylcholine – Triggers muscle fiber contraction.
13. D) Dendrite → Soma → Axon → Synapse – The correct direction of impulse flow.
14. B) The gap in the myelin sheath – Allows saltatory conduction.
15. D) Potassium (K⁺) – Maintains resting potential by being more permeable across the membrane.
16. C) A connection point between neurons – Where transmission occurs.
17. C) Astrocytes – Help regulate what enters the brain from the blood.
18. C) The jumping of action potentials between nodes – Increases speed of impulse conduction.
19. D) Calcium (Ca²⁺) – Triggers neurotransmitter release at synaptic vesicles.
20. B) The neuron rests and cannot fire another impulse – Ensures one-way transmission and recovery.
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