Fig. 1 shows a section through the head of a diver who is descending in a training pool. The diver feels pressure in the ear because the pressure of water o...
Question 1 Report
Fig. 1 shows a section through the head of a diver who is descending in a training pool. The diver feels pressure in the ear because the pressure of water outside the body increases with depth. The labelled tube connects the middle ear to the throat. The trainer tells the diver to swallow gently during descent so that pressure can be equalised on both sides of the eardrum.
(a) Name the structures labelled A and B. [2]
(b) Describe what happens to B when pressure outside the ear is greater than pressure in the middle ear. [2]
(c) Explain how swallowing can reduce discomfort in the diver's ear. [3]
(d) State the name of the fluid-filled part of the inner ear that contains hearing receptor cells. [1]
(e) Explain how receptor cells allow the diver to hear the trainer's voice. [3]
(f) Which type of stimulus is detected by receptor cells in the ear: light or vibrations? [1]
(g) Give one reason why a diver should descend slowly. [1]
Answer Details
(a) A is the Eustachian tube and B is the eardrum. [2]
(b) If pressure outside is greater, the eardrum is pushed inwards. It becomes stretched and cannot vibrate normally. [2]
(c) Swallowing opens the Eustachian tube. Air can then move between the throat and middle ear, making pressure equal on both sides of the eardrum and reducing discomfort. [3]
(d) The fluid-filled inner-ear part containing hearing receptor cells is the cochlea. [1]
(e) The trainer's sound causes vibrations in the ear and cochlear fluid. These stimulate receptor cells, which produce nerve impulses that travel to the brain. [3]
(f) Ear receptor cells detect vibrations. [1]
(g) Descending slowly allows pressure to equalise gradually, reducing the risk of eardrum damage. [1]
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