Gustatory System

1. GustatorySystem the sensory system for the sense of taste Presented by Lim, Erynne Nguyen, Cynthia

2. Structure of the Human Tongue • The tongue has 4 kinds of papillae: -papillae: one of the small, round, or cone-shaped protuberances on the top of the tongue that contain taste buds • 1.foliate papilla: a series of folds on the sides of the tongue in the back 2. circumvallate papilla: organized in an inverted V at the back of tongue 3. fungiform papilla: found scattered across the top front and middle 4. filiform papilla: found across the top

3. Taste Buds • The circumvallate, foliate, and fungiform papillae contain taste budswhile the filiform papilla doesn’t - taste buds: smallest functional of taste; is found on tongue, back of throat and roof of mouth • Taste buds contains several taste receptor cells - taste receptors: a type of receptor which facilitates the sensation of taste • An average person contains 5,000 taste buds!

4. Types of Basic Taste • There are 5 different basic tastes: -Bitter -Salty -Sour -Sweet -Umami -In humans, the different types of taste cells are scattered throughout the tongue. >A common misconception tastes are found in separate regions of the tongue. • Spicy is not a type of basic taste because the sensation doesn’t arise from taste buds -It is the reaction when temperature fibers & nociceptors/pain in the tongue is stimulated -Capsaicin is the active ingredient

5. Taste: Bitter • Bitter: having a sharp, pungent taste or smell -ex: coffee, beer, medicine, poison, etc. • The bitterness serves as an important protective function against recognition of toxic compounds

6. Taste: Salty • Salty: tasting of, containing, or preserved with salt -ex: table salt, pretzels, etc. • Saltiness is tasted when there is a presence of cations -ex: Li+, K+, and most commonly Na+

7. Taste: Sour • Sour: having an acid taste like lemon or vinegar -ex: lemon/lime, wine, spoiled milk, some candies, etc. • Large quantities of sour food, containing acids, will lead to irreversible tissue damage

8. Taste: Sweet • Sweet: having the pleasant taste characteristic of sugar or honey -ex: sugar, candy, cake, ice cream, etc. • Tasted when there is a strong presence of glucose

9. Taste: Umami • Umami: the meaty or savory taste of glutamate proteins or other similar compounds -ex: cheese, soy sauce, etc. • Contains monosodium glutamate and L-glutamate • Recently added as a 5th taste!

10. Brain tastes the taste • When the nerve fibers are stimulated, they send messages through three specialized taste nerves to the brain, where specific tastes are identified -Microvilli(nerve fibers): each of a large number of minute projections from the surface of some cells -The facial nerve (VII)- the anterior two thirds of the tongue -The glossopharyngeal nerve(IX)- the posterior one third of the tongue -A branch of the vagus nerve (X)- the back of the oral cavity. - taste compounds: interact with the tops of these specialized cells which then transmit taste information through the nerve to the brain

11. Taste Disorders • Brain damage can lead to loss of taste • Common taste disorders: • Phantom taste perception: a lingering, often unpleasant taste even though you have nothing in your mouth • Hypogeusia: a reduced ability to taste the 5 basic tastes (sweet, sour, bitter, salty, and umami) • Ageusia: cannot detect any tastes >Complete loss of taste is very rare.

12. Bibliography Internet http://www.nidcd.nih.gov/health/smelltaste/pages/taste.aspx http://www.medicinenet.com/taste_disorders/page2.htm http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Taste.html Book Biology Textbook. McGraw-Hill