Question
(a) Table 2.1 shows some of the effects of alcohol and heroin.
Complete Table 2.1 by writing YES or NO in each of the boxes.
One box has been completed for you.
(b) Tobacco smoke contains harmful chemicals.
State one effect of the following chemicals in tobacco smoke:
Answer/Explanation
Ans:
Question
Heroin is a drug that acts on the nervous system.
(a) Define the term drug.
…………………………………………………………………………………………………………………………………
There are pain receptors in the skin. These receptors transmit impulses along sensory neurones
to the spinal cord.
Fig. 3.1 shows the synapses between sensory neurone A and a relay neurone and sensory
neurone B and a relay neurone, in the spinal cord.
Fig. 3.2 is an enlarged view of the synapse between sensory neurone A and the relay neurone, as
indicated by the circle on Fig. 3.1.
(b) Describe how impulses are transmitted across the synapse.
…………………………………………………………………………………………………………………………………
(c) Suggest how the structure of a synapse ensures that impulses travel in one direction.
…………………………………………………………………………………………………………………………………
(d) When an impulse arrives along sensory neurone B, a different neurotransmitter is released.
This prevents the production of an impulse in the relay neurone.
Molecules of heroin have a similar shape to the neurotransmitter released from these
neurones.
Explain how heroin affects the function of the synapse.
…………………………………………………………………………………………………………………………………
(e) List three stimuli, other than pain, which humans can detect.
1 ……………………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………………….
3 ……………………………………………………………………………………………………………………………….
Answer/Explanation
Ans:
Question
(a) Table 2.1 shows some of the effects of alcohol and heroin.
Complete Table 2.1 by writing YES or NO in each of the boxes.
One box has been completed for you.
(b) Tobacco smoke contains harmful chemicals.
State one effect of the following chemicals in tobacco smoke:
Answer/Explanation
Ans: