Senses 1-4

Question 1

What are the 5 different tastes?

We can distinguish 4,000-10,000 different chemicals with these tastes

Answer 1

Salt
Sweet
Bitter
Sour
Umami

Question 2

Receptors responsible for transmitting taste qualities are located mainly on the dorsal surface of the tongue within structures called ______ which are located in epithelial projections called ______

Answer 2

Taste buds

Lingual Papillae

Question 3

What are the 3 types of lingual papillae on the human tongue?

Answer 3

Circumvallate Papillae: Back of tongue
Fungiform Papillae: Borders of tongue
Filiform Papillae: no taste buds & ‘fills’ the middle of the tongue

Question 4

Taste buds are replaced every ___ days

Answer 4

10 days

Constantly

Question 5

Taste buds contain ____-____ receptor cells sandwiched between supporting cells & basal cells

Answer 5

50-150 receptor cells

Question 6

Receptor cells

Answer 6

Are Epithelial cells are closely linked to neurons & have the ability to excite their associated neuron when they interact w/ a taste stimulus.
Only tip of cell protrudes into oral cavity through a taste pore, & basally

Question 7

Receptor Potentials

Answer 7

• Graded depolarizations.
• A neurotransmitter that is released from the basal membrane of the taste receptor cell when the apical membrane interacts with a tastant, causing a receptor potential & is ALWAYS caused by an increase in intracellular Ca++
• Ca++ enters & stimulates exocytosis of membrane vesicles containing neurotransmitters.
• When it contacts the neuron depolarization sends a signal to the brain.

Question 8

Bitter, Sweet & Umami use which type of receptor?

Answer 8

G-Protein & use intracellular Ca++ stores instead of extracellular stores

Question 9

3 Different properties of the taste sensation pathway allow the brain to distinguish between different sensations.

Answer 9

The proportion of action potentials received
Additional input from smell
Additional input from other types of sensory receptors in the mouth

Question 10

Capsaicin

Answer 10

Chemical found in peppers help us perceive spiciness.

Not a result of a taste receptor but because of the activation of PAIN receptors

Question 11

Perception of taste is produced by neural processing within the primary sensory cortex as it receives action potentials from diff. nerve bundles.
What are the 3 major nerves that contribute to gustation?

Answer 11

• Facial Nerve: receives input from taste receptors located on the anterior 2/3’s of the tongue
• Glossopharyngeal Nerve: Posterior 1/3 of the tongue
• Vagus Nerve: Surface of the epiglottis.
• *All of the nerves converge on the solitary nucleus of the medulla oblongata & arrive to the lateral region of the sensory cortex