TONGUE
The tongue is a muscular organ in the mouth covered with a moist, pink tissue called the mucosa.
It is involved in licking, tasting, breathing, swallowing, and speaking. The papillae present on the
tongue gives it a rough texture. It is covered by a number of taste buds. There are several nerves
in the tongue that help in transmitting taste signals to the brain, and thus helps in taste sensation.
Structure of Tongue
The human tongue is about 3.3 inches in men and 3.1 inches in women. It is located in the oral
cavity. The tongue is divided into three parts:
Tip
Body
Base
The tongue is embryologically divided into the anterior and posterior part. The anterior part is
known as the oral or presulcal part that includes the root attached to the floor of the oral cavity.
While the posterior part is known as pharyngeal or postsulcal part that includes the base forming
the ventral wall of oropharynx.
The tongue is made up of three elements:
Epithelium
Muscles
Glands
Epithelium
The epithelium comprises papillae and taste buds. The taste buds help to sense taste. They are
lined by squamous epithelial tissue and have a broad bottom.
The taste cells are slender, rod-shaped with a nucleus in the centre. The free surface comprises
short taste hair. The taste cells help in detecting taste, which dissolves in saliva for proper
sensation.
Muscles
The tongue muscles are voluntary and contain cross-striated muscular fibres.
Glands
The tongue consists of small and scattered glands. These glands are of three types:
Mucous Glands
Serous Glands
Lymph Nodes
The lymph nodes are very prominent at the posterior part of the tongue and are known as lingual
tonsils.
Nerve Supply
The glossopharyngeal nerve and the chorda tympanic branch of the facial nerve are responsible
for taste sensation. The sensations of pain, touch, temperature are carried by the trigeminal nerve.
Tongue Functions
Following are the important tongue functions:
Mastication
The tongue helps in chewing.
Deglutition
It helps in swallowing food.
Taste
The tongue transmits taste signals to the brain and helps in sensing taste.
Speech
It is an important organ that facilitates speech.
Secretion
It secretes mucous and serous fluid which keeps the mouth moist.
Salivary Glands
Salivary glands comprise three pairs:
Parotid
Submaxillary
Sublingual
Parotid
It opens on the inner surface of the cheek by the duct of Stensen. It is located opposite the second
upper molar tooth.
Submaxillary
It opens by Whartons duct on the floor of the mouth by the sides of the frenulum of the tongue.
Sublingual
It opens by the ducts of Rivinus on the floor of the mouth by the sides of the frenulum of the
tongue.