Physiology of Taste

Question 1

What can taste also be called?

Answer 1

Gustation

Question 2

What does gustation allow for?

Answer 2

• Evaluation of the nutritious content of food

- Prevention of ingestion of toxic substances

Question 3

What are the different modalities of taste and what do they detect?

Answer 3

• Umami (amino acids)
• Sour/Bitter (potentially noxious/poisonous chemicals)
• Sweet (energy-rich nutrients)
• Salty

Question 4

What does salty sensation depend on?

Answer 4

The equilibrium potential of Na+ across taste receptors

Question 5

What does sour sensation depend on, and how is it detected?

Answer 5

Acidity

H+ ions close K+ channels directly or indirectly (via cAMP) which leads to depolarisation

Question 6

How do sweet sensations lead to depolarisation?

Answer 6

2nd messenger system leads to the closing of K+ channels, leading to depolarisation

Question 7

How do bitter and umami tastes get detected?

Answer 7

2nd messenger system that increases intracellular Ca2+, leading to neurotransmitter release

Question 8

What are taste disorders commonly mistaken with?

Answer 8

Olfactory disorders

Question 9

What cranial nerves are involved with taste, and to what nucleus do they transmit the info to?

Answer 9

Facial, Glossopharyngeal and Vagus nerves

Nucleus of the solitary tract (found in the brainstem)

Question 10

What are some causes of taste disorders?

Answer 10

• Head trauma
• Poor oral hygiene
• Upper respiratory tract disorders