Sense Organs; Taste

Question 1

Taste

Answer 1

Taste and smell are chemical senses because they arise from interaction with molecules

Question 2

Gustation

Answer 2

Taste is known as ‘gustation
* Stimulation of chemoreceptors by dissolved chemicals in saliva

• Taste and smell are closely related

Question 3

Taste buds

Answer 3

10,000 in adult. Most on the tongue, but some are on the soft palate, pharynx and epiglottis. Taste buds are found in elevations on the tongue called papillae.

Taste buds contain:
1. Gustatory receptors
2. Basal cells
3. Supporting cells

Question 4

Gustatory cells

Answer 4

Detect taste, live for about 10 days

Question 5

Basal cells

Answer 5

Stem cells that produce new receptor cells

Question 6

Supporting cells

Answer 6

Provide physical support

Question 7

Papillae

Answer 7

Taste buds are found in elevations on the tongue called papillae. Papillae are ridges that form friction / grip foods in oral cavity and provide a larger surface area for taste buds.
There are three types of papillae;
1. Circumvallate papille
2. Fungiform papillae
3. Foliate papillae
The whole surface of the tongue has filiform papillae – tactile receptors that help the tongue move food (feel texture food, not taste)

Question 8

Circumvallate papille

Answer 8

The largest papillae, V-shaped at the back of the tongue

Question 9

Fungiform papillae

Answer 9

Mushroom shaped and are present all over the tongue. They contain about 5 taste buds each

Question 10

Foliate papillae

Answer 10

Located in small trenches at lateral margins of tongue, most degenerate in childhood

Question 11

Taste physiology

Answer 11

Once tastants are dissolved in saliva, they contact the cell membrane of gustatory hairs, which generates an action potential (receptor potential arises differently for different tastants, e.g. salty food, sodium enters channels)

Question 12

Taste Types

Answer 12

Taste is more simple than smell, we can only detect 5 tastes:
1. Sour
2. Sweet
3. Bitter
4. Salty
5. Umami
The complex flavour we enjoy every day arise from different strengths and combinations of stimulation

There is no tongue ‘map’ – responsiveness to the 5 basic modalities is present in all areas of the tongue

Question 13

Taste salivation

Answer 13

Sense of taste triggers salivation and gastric juice secretion (in preparation). Taste is impaired when the mouth is dry.

Question 14

Nerves

Answer 14

There are various nerves that give us sensory information from the tongue – taste and physical sensation.

Information goes to the gustatory nucleus in medulla oblongata and some fibres to the limbic system (emotional link)

Question 15

Nerves; Facial nerve

Answer 15

The facial nerve innervates taste in the anterior 2/3 of the tongue

Question 16

Nerves; Glossopharyngeal

Answer 16

The glossopharyngeal nerve innervates both taste and general sensation of the posterior 1/3 of the tongue

Question 17

Nerves; Trigeminal

Answer 17

The trigeminal nerve supplies general sensation to the anterior 2/3 of the tongue

Question 18

Nerves; Vagus

Answer 18

The vagus nerve innervates the throat and epiglottis

Question 19

Taste buds; cells

Answer 19

Taste buds contain:
1. Gustatory receptors
2. Basal cells
3. Supporting cells

Question 20

Tongue muscles

Answer 20

• The tongue is formed of eight muscles, which are innervated by the hypoglossal nerve (CN XII)