Taste buds

This presentation provides information about taste buds, their structure and transduction of signals from taste buds to brain.

1. Taste buds Sukhbir Kaur

2. Taste Sensation produced when substance in mouth reacts with taste buds is called taste. Four basic taste: sweet , sour , s alty and bitter .

3. Taste buds Taste buds are present on upper surface of tongue, soft palate, upper esophagus and epiglottis . Taste buds have a bility to respond to dissolved molecules and ions called tastants . Taste receptor cells cluster to form taste buds (papillae).

4. Taste buds are present on pappilae -raised protrusions. These are of four types: fungiform , filiform , foliate and circumvallate . Information about taste is transmitted t o brian by : Facial G lossopharyngeal and V agus nerves.

5. Taste buds About 50 -150 taste cells found in a taste bud. These cells represent all 4 tastes. Single taste cell restricted to only single type of receptor. Taste buds have 3 types of cells: Supporting cells, Sensory cells and Basal cells. Taste bud has a pore that opens out to surface of tongue.

6. Transduction of signal from taste bud to brain

7. Transduction Each cell has receptor on apical surface. These receptors are transmembrane proteins. Taste cells are connected to sensory neuron. Receptors for salts are ion channels that allow Na ⁺ to pass . Sour receptors are ion channels that admit H⁺ liberated by sour substances to pass into cell .

8. For bitter taste ,there are 25 diff. T2R receptors that are coupled to G proteins. Two subunits T1R1 and T1R3 coupled with G- protein form receptor for umami taste. For sweet substances, there are G-protein coupled receptors. Two subunits T1R2 and T1R3 are coupled to G proteins.