Ch 22 Taste Bud Anatomy/ Primary taste sensations/ Olfactory

Umami

Japanese word meaning 'delicious flavor'. 'Meaty' taste produced by amino acids in protein

Taste pore

a pit on the epithelial surface of the tongue that opens into a taste bud. Taste hairs project into the taste pore.

Bitter

associated with spoiled food and alkaloids such as nicotine, caffeine, quinine, and morphine. Alkaloids are usually poisonous and bitter taste cause us to reject a food

Supporting cells

lie between olfactory neurons and sustain the receptor cells

Olfactory receptor cells

neurons that detect odors only neurons directly exposed to the external environment lifespan of 60 days then replaced shaped like inverted bowling pins inferior, apical head has 10-20 immobile cilia- olfactory hairs - olfactory hairs have binding sites for odorant molecules basal end of cell tapers to become an axon axons travel through cribiform foramina to olfactory bulb

Gustatory (taste) cells

numerous banana-shaped cells with a tuft of microvilli (taste hairs) on apical surface, specialized neuroepithelial cells that synapse with sensory nerve fibers. Taste hairs serve as receptor surfaces for chemical molecules. live for 7 to 10 days

Salty

produced by metal ions such as sodium and potassium. When these levels fall, we crave salty foods

Sweet

produced by sugars and other organic molecules. Associated with carbohydrates and foods with high caloric content.

Facial nerve VII

receive signals from taste buds on anterior two-thirds of tongue

Glossopharynegal nerve (IX)

receives signals from taste buds on the posterior one third of the tongue

Name the 5 primary taste sensations

salty, sweet, sour, bitter, umami

Olfaction

sense of smell

Basal cell

stem cells that constantly divide and replace the dead gustatory cells. Replacement slows about the age of 50, and taste sensation begins to decline

Basal cells

stem cells to continually replace olfactory receptor cells

supporting cells

surround and resemble gustatory cells. have no sensory function

olfactory epithelium

two postage stamp-sized patches of epithelium that line the superior region of the each nasal cavity . Covers both superior nasal conchae, upper nasal septum, and the inferior surface of the cribiform plate of each nasal fossa. Composed of three cell types: olfactory receptor cells, supporting cells, basal cells

Sour

usually associated with acids (H+) in foods such as citrus fruits