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Taste Buds: Small sensory organs which contain gustatory receptor cells, basal cells, and supporting cells. Taste buds in humans are found in the epithelia of the tongue, palate, and pharynx. They are innervated by the Chorda tympani nerve (a branch of the facial nerve) and the Glossopharyngeal nerve.

The Tongue and Taste Buds

JoVE 10850

The surface of the tongue is covered with various small bumps called papillae, which either distribute what has been ingested (filiform papillae) or contain the sensory taste (or gustatory) receptor cells (fungiform, circumvallate, and foliate papillae). Embedded within each taste-related papilla are the taste buds—clusters of 30 to 100 gustatory receptor cells.

Gustatory receptor cells extend finger-like projections called gustatory hairs (or microvilli) into a region known as the taste pore. Here, many of the cells contain receptors that detect different tastants—the molecules that can be tasted. The average number of taste buds varies significantly among individuals, with estimates ranging from 2,000-10,000 taste buds. Taste cells have a lifespan of about 10-14 days and are continually replaced. Thus, each taste bud contains taste cells at different stages of development. Aside from the filiform papillae, which do not contain taste buds, the mushroom-shaped fungiform papillae are the most numerous. Fungiform papillae are predominantly located on the anterior two-thirds of the tongue and contain between one and eight taste buds each. In contrast, the other two types of papillae—circumvallate and foliate—contain more than 100 taste buds per papilla. Circumvallate papillae, the largest type, are located at the back o

 Core: Sensory Systems

Gustation

JoVE 10851

Gustation is a chemical sense that, along with olfaction (smell), contributes to our perception of taste. It starts with the activation of receptors by chemical compounds (tastants) dissolved in the saliva. The saliva and filiform papillae on the tongue distribute the tastants and increase their exposure to the taste receptors.

Taste receptors are found on the surface of the tongue as well as on the soft palate, the pharynx, and the upper esophagus. On the tongue, taste receptors are contained within structures called taste buds. The taste buds are embedded within papillae, which are visible on the tongue surface. There are three types of papillae that contain taste buds and their receptors. Circumvallate papillae are the largest papillae and are located near the back of the tongue. Foliate papillae resemble folds on the side of the tongue. Fungiform papillae are found across the front three-quarters of the tongue but are less concentrated in the middle of the tongue. There are five basic tastes: salty, sour, sweet, bitter, and savory (or umami). The perception of salty taste is caused by tastants that release sodium ions upon dissolution. Sour taste, by contrast, is produced by the release of hydrogen ions from dissolved acidic tastants. Salty and sour tastants produce a neural response by depolarizing the membrane directly (salty tastants) or via ion chan

 Core: Sensory Systems

Technique to Collect Fungiform (Taste) Papillae from Human Tongue

1Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, 2Department of Internal Medicine and Department of Psychiatry, School of Medicine, Washington University in St. Louis, 3Veterans Affairs Medical Center, 4School of Dental Medicine, Department of Biochemistry, University of Pennsylvania-School of Medicine, 5Monell Chemical Senses Center, 6Monell Chemical Senses Center

JoVE 2201

 Medicine

Cranial Nerves Exam II (VII-XII)

JoVE 10005

Source:Tracey A. Milligan, MD; Tamara B. Kaplan, MD; Neurology, Brigham and Women's/Massachusetts General Hospital, Boston, Massachusetts, USA


The cranial nerve examination follows the mental status evaluation in a neurological exam. However, the examination begins with observations made upon greeting…

 Physical Examinations III
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