The tongue is a voluntary muscular structure that occupies the floor of the mouth. It is attached by its base to the hyoid bone and by a fold of its mucous membranes covering,called the frenulum,to the floor of the mouth. The superior surface consists of straified epithelium, with numerous papillae. Many of these contain sensory receptors (specialised nerve endings) for the sense of taste in the taste buds. There are several types of papilla,however no clear relationship between these and discrimination of different tastes has been found.
BLOOD SUPPLY.
The main arterial blood supply to the tongue is by the lingual branch of the external carotid artery. Venous drainage is by the lingual vein,which joins the internal jugular vein.
NERVE SUPPLY
The nerves involved are:
- The hypoglossal nerves( 12th cranial nerves) which supply the voluntary muscle.
- The lingual branch of the mandibular nerves,which arise from the 5th cranial nerves,are the nerves of somatic(ordinary) sensation
- The facial and glossopharyngeal nerves(7th and 9th cranial nerves) the nerves of taste.
FUNCTIONS OF THE TONGUE.
The tongue plays important part in:
- Chewing(mastication).
- Swallowing(deglutition).
- Speech.
- Taste
Nerve endings of the sense of taste are present in the papillae and widely distributed in the epithelium of the tongue,soft palate,pharynx and epiglottis.
