Responding to the Environment: Nervous System is one of 10 topics in the Grade 12 Life Sciences CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. Which part of a neuron carries the nerve impulse away from the cell body towards the next neuron or effector?
The axon
The dendrite
The cell body
The nucleus
Answer: The axon — The axon is the long extension of a neuron that conducts the nerve impulse away from the cell body towards the next cell.
Easy
2. The small gap between two neurons across which neurotransmitters diffuse is called a:
Synapse
Node of Ranvier
Dendrite
Axon terminal only, with no gap involved
Answer: Synapse — A synapse is the junction between two neurons (or a neuron and an effector), where neurotransmitters are released to pass the signal across the gap.
Medium
3. What is the function of the myelin sheath surrounding many axons?
It insulates the axon and allows saltatory conduction, greatly speeding up impulse transmission
It generates the nerve impulse itself
It stores neurotransmitters for release at the synapse
It converts electrical impulses into chemical signals within the axon
Answer: It insulates the axon and allows saltatory conduction, greatly speeding up impulse transmission — The myelin sheath insulates the axon, forcing the impulse to jump between nodes of Ranvier (saltatory conduction), which transmits the impulse much faster than in an unmyelinated axon.
