Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
TASTE
Dr. Selvakumar
Department of Physiology
Learning objectives
Draw and explain the location and function of gustatory
receptors
Draw and explain taste pathway
Descr...
Contents
Taste
Taste sensations
Taste receptors
Taste pathway
Different taste perception
Taste threshold
Factors influence...
Taste
Taste drives appetite and protects us from poisons.
We like the taste of sugar because we have an absolute
requireme...
Taste
We have a need for protein--amino acids
- the building blocks for proteins
The "new" taste quality umami - which is ...
Primary Taste sensations
Five types
1.Sweet- Sugar
2.Salt - NaCl
3.Sour - Acid
4.Bitter - Caffiene
5.Umami- Aji-no-moto
Taste bud
sense organ for taste is
the taste bud which
contains the receptor
cells
taste buds are present
on the palate, p...
Taste buds
Ovoid bodies measuring 50–70 µm
Made up of supporting cells, basal cells
and 5 -18 receptor cells called gustat...
Papillae
Taste papillae can be seen on the tongue as little red
dots, or raised bumps, particularly at the front of the
to...
Filiform
papillae
Fungiform
papillae
salty
sour
Taste
Taste pathway
Sensory nerve fibres from taste buds travel by
three different nerves
– from ant 2/3 of tongue via chorda ty...
Taste buds

Taste fibres in VII, IX & X
nerves( I Order Neuron)

Tractus solitarius
(in medulla)

Nucleus tractus solit...
BASIC TASTE SENSATIONS
PRODUCED BY MECHANISM OF
STIMULATION
SENSITIVE
PART OF
TONGUE
SWEET Sugars, glycols & aldehydes. ↑ ...
Threshold & Adaptation
Order of increasing threshold
– bitter has lowest threshold, then sour
followed by sweet & salt eq...
Taste Thresholds
Substance Taste Threshold conc
µmol / lit
Hydrochloric
acid
Sour 100
Strychnine Hcl Bitter 1.6
Glucose
So...
Gustation and Olfaction
Have you ever wondered why food loses its flavor
when you have a cold?
It's not your taste buds' f...
Integration of
Smell & Taste
Importance of olfaction
In food & sex motivated behaviour olfaction plays
an important role in sub human species & a minor...
After effects
Some substances alter the taste of other
substances
A plant protein miraculin when applied to
tongue makes a...
Disorders
Ageusia: Loss of taste sensation
Hypogeusia : Taste sensation is less
Dysgeusia : Disturbed taste sense
Taste bl...
Thank u
Taste
Taste
Taste
Taste
Upcoming SlideShare
Loading in …5
×

Taste

Taste

  • Login to see the comments

Taste

  1. 1. TASTE Dr. Selvakumar Department of Physiology
  2. 2. Learning objectives Draw and explain the location and function of gustatory receptors Draw and explain taste pathway Describe how different types of tastes are perceived by an individual Mention the factors influencing taste sensation Biefly describe the terms ageusia, hypoguesia & dysguesia
  3. 3. Contents Taste Taste sensations Taste receptors Taste pathway Different taste perception Taste threshold Factors influences taste Taste and olfaction Applied aspects.
  4. 4. Taste Taste drives appetite and protects us from poisons. We like the taste of sugar because we have an absolute requirement for carbohydrates (sugars etc.). We get cravings for salt because we must have sodium chloride. Bitter and sour cause aversive, avoidance reactions because most poisons are bitter .
  5. 5. Taste We have a need for protein--amino acids - the building blocks for proteins The "new" taste quality umami - which is the meaty, savoury taste drives our appetite for amino acids. (This taste has been known to the Japanese for a long time - but has only recently been recognized by the West.)
  6. 6. Primary Taste sensations Five types 1.Sweet- Sugar 2.Salt - NaCl 3.Sour - Acid 4.Bitter - Caffiene 5.Umami- Aji-no-moto
  7. 7. Taste bud sense organ for taste is the taste bud which contains the receptor cells taste buds are present on the palate, pharynx and papillae of tongue
  8. 8. Taste buds Ovoid bodies measuring 50–70 µm Made up of supporting cells, basal cells and 5 -18 receptor cells called gustatory receptors Receptor cell has a number of microvilli projecting into the taste pore & has a life cycle of few days Unmyelinated nerve endings innervates at the base of the receptor cells
  9. 9. Papillae Taste papillae can be seen on the tongue as little red dots, or raised bumps, particularly at the front of the tongue. Fungiform: tip of the tongue Vallate: arranged in a ‘v’ on the back of the tongue Filliform: cover the dorsum of tongue, do not contain taste buds Foliate: lateral border of tongue
  10. 10. Filiform papillae Fungiform papillae salty sour
  11. 11. Taste
  12. 12. Taste pathway Sensory nerve fibres from taste buds travel by three different nerves – from ant 2/3 of tongue via chorda tympani branch of facial nerve – from post 1/3 of tongue via glossopharyngeal nerve – from pharynx, epiglottis & palate via vagus
  13. 13. Taste buds  Taste fibres in VII, IX & X nerves( I Order Neuron)  Tractus solitarius (in medulla)  Nucleus tractus solitarius (II order N.)  ? Cross over Joins medial leminiscus  VPM nucleus of thalamus (III order N.)  Brodman’s area 43
  14. 14. BASIC TASTE SENSATIONS PRODUCED BY MECHANISM OF STIMULATION SENSITIVE PART OF TONGUE SWEET Sugars, glycols & aldehydes. ↑ cyclic AMP→ ↓K+ conductance Tip BITTER Alkaloids ↑ IP3→ ↑Ca++ release Posterior SOUR H+ ions Blocking K+ channels Postero lateral ½ SALT UMAMI Anions of ionised salts Monosodium glutamate ↑ Na+ ion permeability Stimulates glutamate Receptor mGluR4 Antero lateral ½ _
  15. 15. Threshold & Adaptation Order of increasing threshold – bitter has lowest threshold, then sour followed by sweet & salt equally Taste receptors show adaptation by elevating the threshold level
  16. 16. Taste Thresholds Substance Taste Threshold conc µmol / lit Hydrochloric acid Sour 100 Strychnine Hcl Bitter 1.6 Glucose Sodium Chloride Sweet Salt 80,000 2000
  17. 17. Gustation and Olfaction Have you ever wondered why food loses its flavor when you have a cold? It's not your taste buds' fault. Blame your stuffed-up nose. Seventy to seventy-five percent of what we perceive as taste actually comes from our sense of smell. Taste buds allow us to perceive only bitter, salty, sweet, sour and savoury flavors. It's the odor molecules from food that give us most of our taste sensation.
  18. 18. Integration of Smell & Taste
  19. 19. Importance of olfaction In food & sex motivated behaviour olfaction plays an important role in sub human species & a minor role in humans. Thus olfactory impulses are projected both to – Neocortex perception & discrimination of odours – Limbic system Emotional (Amygdala) , motivational, behavioral & physiological effects of odours
  20. 20. After effects Some substances alter the taste of other substances A plant protein miraculin when applied to tongue makes acid taste sweet Betel nut & amla make water taste sweeter
  21. 21. Disorders Ageusia: Loss of taste sensation Hypogeusia : Taste sensation is less Dysgeusia : Disturbed taste sense Taste blindness : Phenyl thio carbamide (PTC) tastes sour to 70% of population but tasteless to other 30%
  22. 22. Thank u

×