Specific learning outcomes Outline different types of taste Describe the taste pathway Explain the role in nutrition Taste primary taste sensations Sweet organic substances polysaccharides glycerols alcohol ketones chloroform ID: 1043252
Download Presentation The PPT/PDF document "Taste Dr Mohammed Jeelani" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. Taste Dr Mohammed Jeelani
2. Specific learning outcomesOutline different types of taste Describe the taste pathway Explain the role in nutrition.
3. Taste (primary taste sensations)Sweet: organic substances (polysaccharides, glycerol's, alcohol, ketones, chloroform)Salt: ionizing substances releasing Na+ ionsSour: acids which release H+ ions, sourness depends on the hydrogen ion concentration in the given acid
4. Bitter: alkaloids like quinineOrganic compounds like morphine, caffeine, urea, inorganic salts of magnisium, ammonia and calciumDue to cationsUmami: pleasant and sweet taste sensationProduced by monosodium glutamate (MSG)
5. Taste BudReceptors for tastePresent on walls of papillaConsists ofReceptor cellsBasal cellsSupporting cells
6. Nerve supplyAnterior 2/3rd of tongue- Chorda tympani, branch of facial nervePosterior 1/3rd of tongue- glossopharyngeal nerve
7. Taste pathway
8. Mechanism of appreciation of tasteTaste producing substance dissolves in saliva and comes in contact with the villi through the taste pores present in the taste budThis brings changes in receptors cells, resulting in generation of generator potentialCauses release of neurotransmitter at the synapse between receptor cell and sensory nerve
9. Action potential is generated at the sensory neuronImpulses from receptor cells are carried to foot of postcentral gyrus in parietal lobe of cerebral cortex where different taste sensations are appreciated
10. AppliedAgeusia : absence of taste sensationHypogeusia : decreased taste sensationDysgeusia or Parageusia : unpleasent perception of taste sensation
11. Role in nutritionTaste Preference and Control of the DietChoose certain types of food in preference to othersTaste preferences often change in accord with the body’s need for certain specific substances..
12. Experiment demonstrating ability of animals to choose food in accord with the needs of their bodies.1st adrenalectomized, salt-depleted animals automatically select drinking water with a high concentration of sodium chloride in preference to pure water (sufficient to supply the needs of the body and prevent salt-depletion death.)2nd, an animal given injections of excessive amounts of insulin develops a depleted blood sugar, and the animal automatically chooses the sweetest food from among many samples. 3rd, calcium depleted parathyroidectomized animals automatically choose drinking water with a high concentration of calcium chloride
13. The same phenomena are also observed in everyday life Human beings reject any food that has an unpleasant sensation (protects our bodies from undesirable substances).Mechanism is located in the central nervous system (previous experience with unpleasant or pleasant tastes plays a major role in determining one’s taste preferences.)Eg: if a person becomes sick soon after eating a particular type of food, the person generally develops a negative taste preference, for that particular food thereafter
14. ReferencesGuyton and Hall Textbook of Medical Physiology 13th Edition (Saunders 2016) Chapter 54, pp. 685-688