Taste and Smell

Question 1

List the cells in taste bud:

Answer 1

• Type 1: irregular nucleus, dark granule; salt tasting
• Type 2: Big round nucleus; salt tasting
• Type 3: Intermediate cells
• Type 4: Basal cells

Question 2

List the taste modalities

Answer 2

• G-protein coupled receptors: umami, sweet, bitter

- Channels: sodium, sour/carbonate

Question 3

Describe taste sensing

Answer 3

Taste buds innervated by:

• CN VII - Facial nerve
• CN IX - Glossopharyngeal nerve
• CN X - Vagus nerve

Senses from taste buds go through: Medulla -> Pons -> Cortex.
“Flavour” is the perception of taste, and is mostly smell.

Question 4

Describe spicy

Answer 4

• Not a real taste

- Sensed by CN V - Trigeminal nerve

Question 5

Describe smell organ

Answer 5

Olfactory epithelium:

• Nerves from olfactory bulb travel through cribriform plate and olfactory epithelium.
• Olfactory glands produce mucus on surface.
• Mucous: protects olfactory nerve cilia, media for dissolving chemicals for sensing.

Question 6

List the disorders in taste and smell

Answer 6

• “-geusia” = taste disorder
• “-osmia” = smell disorder
• “hypo-“ = reduced
• “A-“ = inability
• “Dys-“ = abnormal