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In vertebrates, the two ears perform the functions of hearing and balancing. The ear of man is located in the temporal bone on the skull.

The ear has three distinct parts namely;

(i) The outer ear.

(ii) The middle ear.

(iii) The inner ear.

 

(i) The Outer Ear

This consists of the pinna, an outer ear tube or auditory canal called the external auditory meatus and the ear drum / tympanum is made of cartilage covered by skin. It collects sound waves and directs them along the external auditory meatus to the tympanic membrane (eardrum).It also detects the direction of sound waves.

The auditory meatus is a narrow passage which contains fine hairs and wax- producing glands. The wax produced prevents entry of insects, germs and dust into the ear.

The tympanum is a thin tissue which separates the outer ear from the middle ear. It pulsates when sound waves strike it.

(ii) The Middle ear

This is a small, air filled chamber buried in the skull. It contains three tiny bones called ossicles that articulate with one another and form a bridge across the middle ear held in place by muscles.

Lesson tags: Biology Lesson Notes, Biology Objective Questions, SS3 Biology, SS3 Biology Evaluation Questions, SS3 Biology Evaluation Questions First Term, SS3 Biology First Term, SS3 Biology Objective Questions, SS3 Biology Objective Questions First Term
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