Question

How does ear help in maintaining equilibrium?

Answer 1

Hint: Ear in humans is formed of three parts- Externa ear, middle ear and inner ear. Internal ear is the soft, whitish part or ear that helps in maintaining equilibrium and is also called membranous labyrinth. It is also filled with a fluid called endolymph.

Complete answer:
Human ear has two types of receptors:
> Phonoreceptors to receive auditory stimuli.
- The phonoreceptors of organs of Corti of cochlea are sensitive to sound waves of frequency ranging from 20 to 20000 cycles/ second or Hertz.
- In hearing, different parts of the ear perform different functions. Pinna receives sound, an external auditory canal concentrates the sound waves to increase their pressure to strike and freely vibrate the eardrum and middle ear conducts the sound vibrations to fenestra ovalis membrane after increasing their force at ear drum.

> Statoreceptors to control the balance of body and postural changes.
- The balance of the body and posture are maintained by the statoreceptors present in the cristae ampullas of semicircular ducts and the maculae of vestibule.
- Cristae controls the dynamic equilibrium i.e. maintenance of position of body when in motion and equilibrium during angular acceleration i.e. turning or rotational movements of head. As three semicircular ducts are there in three different directions so these can detect the disturbances in position in different directions.
- Maculae controls the static equilibrium i.e. maintenance of position of head or body in relation to force of gravity and linear acceleration i.e. rapid forward movements in straight line.

Note: Semicircular canals and the vestibule of the inner ear together helps in maintain the balance and equilibrium of the body. Phonoreceptors of the human ear are most sensitive to sound waves of 1000 cycles per second. Human ear can differentiate quality as well as quantity of sound waves.