What is the function of the vestibular apparatus of the internal ear ?

Options

A. It equalizes air pressure on the two sides of the ear drum.
B. It maintains equilibrium of the body
C. It collects sound vibrations from air.
D. It acts as auditory receptors.

Answer

To answer the question about the function of the vestibular apparatus of the internal ear, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Vestibular Apparatus**: The vestibular apparatus is a complex structure located in the inner ear. It consists of the semicircular canals and the otolithic organs (utricle and saccule).

2. **Identifying Functions**: The primary function of the vestibular apparatus is to help maintain balance and equilibrium. It detects changes in head position and motion.

3. **Evaluating Options**:
- **Option 1**: "It equalizes ear pressure on the two sides of the eardrum." - This is incorrect as the Eustachian tube performs this function.
- **Option 2**: "It maintains the equilibrium of the body." - This is correct, as the vestibular apparatus is responsible for balance.
- **Option 3**: "It collects sound waves from the ear." - This is incorrect; sound waves are collected by the outer ear (pinna).
- **Option 4**: "It acts as the auditory receptors." - This is also incorrect; auditory receptors are primarily located in the cochlea.

4. **Conclusion**: Based on the evaluation of the options, the correct answer is that the vestibular apparatus maintains the equilibrium of the body.

### Final Answer:
The function of the vestibular apparatus of the internal ear is to maintain the equilibrium of the body.