Sense of Hearing and Balance – The Ear

Topic Content:

In mammals, the ear contains the sense organs of hearing and balance. A mammal has two ears, one on either side of the head. The greater part of the ear lies inside the skull.

Structure of the Ear:

The ear may be divided into three main parts namely;

• The outer ear
• the middle ear
• and the inner ear (labyrinth).

The Outer Ear:

The outer ear consists of the pinna, ear tube (auditory meatus), and the eardrum (tympanic membrane).

Pinna: it is present only in mammals. It is made up of soft cartilage covered with skin. It is flexible. The pinna, apart from detecting the direction of sound, collects sound waves and directs them along the ear canal or external auditory meatus.

External Auditory Meatus: also known as the external auditory canal, it is a narrow passage which contains fine hairs, oils, and wax (secretes by glands) to trap germs and dirt.

Eardrum or Tympanic Membrane:   It separates the outer ear from the middle ear. It