Eustachian tube
- ICSE Class 10, Unit 3 Human Anatomy and Physiology
The Eustachian tube joins the middle ear to the throat and keeps the air pressure equal on both sides of the eardrum.
The middle ear is a small air space behind the eardrum. Air outside presses on the eardrum from one side. The Eustachian tube lets air in or out of the middle ear, so the pressure inside matches. Then the eardrum can move freely and pass on sound.
Because the tube opens into the throat, it is also a path for germs. A throat infection can travel up it into the middle ear.
A small example
When a plane climbs or lands, your ears may feel blocked. Swallowing or yawning opens the Eustachian tube. Air moves, the pressure evens out, and your ears "pop".
Where marks go
The 2025 ICSE Biology paper asked why a throat infection led to earache, for 2 marks. The marking scheme lists the Eustachian tube joining throat and ear, germs travelling from throat to ear, and irritation of the nerves linking them. In CISCE's report on the 2025 Biology paper, examiners name answers that blamed a cold or a general infection without naming the tube. Others left out that the germs travelled from throat to ear.
The 2027 specimen paper asks the same idea directly: name the structure that connects the throat and ear. A 2-mark reason needs both the structure and the route. See value points.
Sources
Facts last checked against these sources on 30 September 2026.
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