These seven original questions follow the four lessons in the chapter. Answer in full sentences, then open the model answer.
Questions
Question 1. Put these in the order of a reflex arc: motor neurone, receptor, effector, sensory neurone, spinal cord.
Answer
Receptor, sensory neurone, spinal cord, motor neurone, effector. The stimulus comes before the receptor, and the response comes after the effector.
Question 2. A cyclist’s hand jerks off a hot exhaust pipe. State the stimulus, the effector and the response.
Answer
The stimulus is the heat. The effector is the arm muscle.
The response is that the arm muscle contracts and the hand is pulled away.
Question 3. Explain why a reflex action is faster than a voluntary action.
Answer
In a reflex, the impulse passes through the spinal cord and does not go to the brain for a decision. The pathway is shorter, so the response is faster and automatic.
Question 4. State two differences between the nervous and endocrine systems.
Answer
The nervous system sends electrical impulses along neurones, but the endocrine system releases hormones into the blood.
The nervous system gives a fast, short response, whereas the endocrine system gives a slower, longer-lasting response.
Question 5. Describe how a message crosses a synapse.
Answer
The impulse reaches the end of the first neurone, which releases neurotransmitter into the synapse.
The neurotransmitter diffuses across the gap and binds to receptors on the next neurone, which starts a new impulse.
Question 6. Explain why impulses cross a synapse in one direction only.
Answer
Only the end of the first neurone releases neurotransmitter, and only the next neurone has receptors for it. The message therefore cannot pass backwards.
Question 7. A student smells toast and her mouth waters. Name the receptor and the effector, and state which one is a gland.
Answer
The receptor is the nose, which detects the chemicals from the toast.
The effector is the salivary gland, so the effector is the gland. Its response is to release saliva.
If you got these wrong
Questions 1 to 3 point to tracing a reflex arc. Question 4 uses comparing nervous and endocrine coordination.
Questions 5 and 6 need explaining synaptic transmission within syllabus scope. Question 7 comes from relating receptors, effectors and responses.
Log each slip in the mistake log and paper-error review, then build a timed set with the timed original practice session builder.
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