The sense of taste originates from specialized receptor on the surface of the tongue, the taste buds. These receptors can pick up different "tastes" based on their chemical nature. Contrary to popular "belief", that different taste maps to different areas on the tongue, taste qualities are found in all regions of the tongue. Some areas are more sensitive to certain chemicals (tastes) than others. The original "taste map", described in the early 1900s, was described due to a mistranslated German research paper. (Those who can read German can read the article here). The misreported taste map is shown below:
(from library.thinkquest.org)
The taste receptors are located on raised portions of the tongue called "papillae". Based on their appearance they are classified as:
1. Fungiform papillae -Mushroom like, located on the tip of the tongue. Innervated by CN VII
2. Foliate papillae -Ridges & Grooves that run on the lateral side of the tongue. Innervated by CN VII (anterior half) and CN VIII (posterior half)
3. Circumvallate papillae -Arranged in a circular shaped row, they are least numerous. They are located at the back of the tongue, innervated by CN VIII
The taste sensation is thus sub served by two cranial nerves, the CN VII and CN VIII. The following video has provides more info regarding pathway for taste.
Burning mouth syndrome is a condition of oral cavity which is characterized by painful and burning sensation in mouth. The actual cause for burning mouth syndrome is often difficult to discern. Their is a website dedicated to burning mouth syndrome, which can be browsed here
The condition can cause redness (inflammation) of the entire oral cavity including lips, tongue and cheek mucosa.
Recently it has been suggested that hypothyroidism may lead to burning mouth syndrome. Your task to find evidence that supports this theory.