How does the function of the semicircular canals differ from the function of thesaccule and utricle?

The semicircular canals and the saccule and utricle are all part of the vestibular system, which is responsible for maintaining our body's balance. However, they have different functions.

1. Semicircular Canals: There are three semicircular canals in each ear, and they are positioned at right angles to each other. These canals are filled with a fluid called endolymph and contain a motion sensor with tiny hairs whose ends are embedded in a jelly-like cupula. The semicircular canals detect rotational movements, like when you shake your head 'no' or nod 'yes'. When your head moves, the fluid inside the canals moves and stimulates the tiny hairs, sending a signal to your brain about the direction in which your head is turning.

2. Saccule and Utricle: These are two small organs located in the vestibule (the part of the inner ear between the semicircular canals and the cochlea). They are filled with a jelly-like substance and contain tiny crystals. The saccule and utricle detect linear movements and the force of gravity. The saccule is responsible for vertical movements, like when you're in an elevator. The utricle, on the other hand, detects horizontal movements, like when you're in a car. When you move, the crystals move, stimulating the hair cells to send signals to your brain about your body's position and movement.

In summary, while the semicircular canals are responsible for detecting rotational movements, the saccule and utricle are responsible for detecting linear movements and the force of gravity.