How many main types of papillae are present on the surface of the tongue?

$A$: Receptors in the tendons and joints provide information regarding the position and movements of different parts of the body.
$R$: These are termed as noci-receptors.

Assertion : Tongue is a gustatoreceptor.
Reason : Receptors for gustatory sensations are located in taste buds.

The movement of the tongue is primarily under the control of which cranial nerve?

State the type of cells in the olfactory epithelium.

Explain the structure and function of the tongue.