SENSE ORGAN - TONGUE - ANATOMY & PHYSIOLOGY OF GUSTATION - TASTE SENSATION For B.Pharm, Pharm.D, D.Pharm & Nursing students.

1. 
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ANATOMY OF TONGUE
PHYSIOLOGY OF GUSTATION
By: Dr.S.Kameshwaran.

2. Chemical Senses
- Taste & smell:
(Both determine the flavour of food)
Taste & smell are closely linked even though they
involve different receptors and receptive
processes.

3. Taste sensation
5 primary tastes
♥ Sour – stimulated by acids
♥ Sweet – stimulated by sugars, alcohols, some amino acid
♥ Bitter – stimulated by bases
♥ Salty – stimulated by metal ions
♥ Umami - Meaty or savory taste/ pleasant taste

4. Sensitivity of the taste buds in different
locations.
 Anterior tongue is
more sensitive to
sweet and salty
substances
 Posterior tongue is
more sensitive to bitter
substances.
 Lateral tongue is more
sensitive to sour
substances.

5. Taste Receptors:
 Taste receptors are known as ‘Chemoreceptors’
 Chemoreceptors housed in taste buds
 Taste receptors have life span of about 10 days
 In association with food intake, influence flow of
digestive juices and affect appetite
Taste buds located in:
 Tongue
 Epiglottis
 Soft Palate
 Pharynx

6. Taste buds
 Most are on the tongue.
 Taste buds present within Papillae of tongue
 The different types of papillaes are
 Filiform - rough, conical shape, few taste buds
 Fungiform – scattered; most numerous on sides and
tips
 Circumvallate –largest; least numerous; back of
tongue
Taste pore
 Opening through which fluids in mouth come into contact
with surface of receptor cells
Taste receptor cells
 Modified epithelial cells with surface folds called microvilli
 Plasma membrane of microvilli contain receptor sites that
bind selectively with chemical molecules

8. 
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
Second level

Third level

Fourth level
»
Fifth level
Location and Structure of Taste Buds

9. Anatomy of Taste Buds

10. Taste Buds

11. ANATOMY OF TASTE BUDS
₡ 10,000 taste buds found on
tongue, soft palate & pharynx
₡ Taste buds consist of:
₡ ~50 receptor cells (type 3)
surrounded by supporting cells
₡ Basal cells (type 1 &2)
develop into supporting cells
then receptor cells
₡ Gustatory hairs project
through the taste pore
₡ Life span 10 days

12. ANATOMY OF TASTE BUDS

13. Taste information sent to the
CNS
via
Cranial nerves # 7, 9 & 10
to
The taste nucleus
(n. tractus solitarius)
to
Thalamus
to
Primary gustatory cortex
Taste Pathway

14. Chemicals in the food

Dissolute in Saliva

Contact with gustatory hair cells or receptor cells

Depolarization of taste cells

Generation of action potential in associated sensory
neuron

Relayed to the gustatory cortex

Recognition of Taste
Physiology of Taste

15. Clinical considerations
♠ Ageusia: Absence of sense of taste
♠ Dysgeusia: Disturbed sense of taste
♠ Hypogeusia: Diminshed sense of taste
♠ Hypergeusia: increased sense of taste

16. THANK U