Tongue: Papillae and Taste Buds - Practice Questions & MCQ

• The tongue is the voluntary musculo-sensory and glandular structure.
• It occupies the floor of the mouth.
• A fold of mucous membrane on the underside of the tongue is called the lingual frenulum.
• It attaches the tongue to the floor of the mouth.
• An inverted V-shaped furrow called sulcus terminalis divides the tongue into two parts:
  • Anterior oral part
  • Posterior pharyngeal part
• At the apex of the sulcus terminalis, a small pit is seen. It is called the foramen caecum.
• It is the remnant of the upper part of the thyroglossal duct (site of thyroid gland origin)
• The top and sides of the tongue are studded with papillae.
• There are four types of papillae, three of them are present in humans.
  • Fungiform papillae cover a large area of the tongue. They contain 8-10 taste buds in each papilla.
  • Filiform papillae are long and thin. These are located at the centre of the tongue. They have touch receptors that help the tongue move food around in the mouth.
  • Circumvallate papillae are the largest papillae present at the base of the tongue. These are around 8-10 in number and each one of them bears around 200 taste buds.
  • Foliate papillae are present in rabbit and absent in humans.
• The pharyngeal part of the tongue does not have papillae but have irregular lymph nodes called lingual tonsils.

Taste Buds:

• A taste bud is a modified epithelial cell.
• It has a small cavity-like opening to the surface through a gustatory pore. 
• Each taste bud contains several specialized taste cells (gustatory receptor cells) for the transduction of taste stimuli.
• These receptor cells release neurotransmitters when certain chemicals in ingested substances (such as food) are carried to their surface in saliva. 
• Neurotransmitter from the gustatory cells can activate the sensory neurons in the facial and glossopharyngeal cranial nerves.

Diagram of Taste bud is shown below :