Physiology of taste and smell

Question 1

What type of cells are the taste and smell receptors?

Answer 1

Chemoreceptors

Question 2

What do they provide (protective effect)?

Answer 2

Quality control checkpoint as poisons taste bitter and off food smells bad and tastes sour/acidic

Question 3

What is taste perception influenced by?

Answer 3

Information from the smell receptors

Question 4

What is the medical name for taste?

Answer 4

Gustation

Question 5

What is the organ of taste?

Answer 5

The taste bud

Question 6

What is the half life of taste receptor cells?

Answer 6

10 days

Question 7

What cells make up the taste bud?

Answer 7

receptor and support cells (and basal cells)

Question 8

What is the function of basal cells?

Answer 8

-

Question 9

Where are taste buds present?

Answer 9

Tongue, palate, epiglottis and pharynx

Question 10

where do the majority of taste buds sit?

Answer 10

the paillae of the tongue

Question 11

What are papillae?

Answer 11

Finger like projections that give rise to the rough appearance of the dorsum of the tongue

Question 12

What are the 4 types of papillae?

Answer 12

Filliform, fungiform, vallate and foliate

Question 13

Which papillae contain taste buds?

Answer 13

Fungiform, foliate and vallate

Question 14

Which pallae are most numerous?

Answer 14

Filliform

Question 15

How is taste conducted?

Answer 15

A tast provoking chemical will bind and produce a receptor potential (depolarising) and this iniates APs in afferent nerve fibres which will synapse with the receptor cells. The signals are conveys to the cortical gustatory areas via the brainstem and CN.

Question 16

Which cranial nerves are involved in taste?

Answer 16

Facial nerve (via the chorda tympani) carries signal from the first 2/3 of the tongue.
Glossopharyngeal (9) will supply posterior third
Vagus (10) will supply areas other than the tongue.

Question 17

What is the medical word for smell?

Answer 17

olfaction

Question 18

What is Aguesia?

Answer 18

Loss of taste

Question 19

What is hypogeusia?

Answer 19

Reduction in taste

Question 20

What is dysgeusia?

Answer 20

Distortion of taste

Question 21

What does each olfactory receptor cell have?

Answer 21

A thick and short dendrite and an expanded end called the olfactory rod

Question 22

Where do cilia project from into the olfactory mucosa?

Answer 22

the olfactory rods

Question 23

How many cillia per rod?

Answer 23

10-12

Question 24

What is the life span of an olfactry receptor?

Answer 24

2 months

Question 25

What act as precursors for new olfactory receptor cells?

Answer 25

Basal cells

Question 26

what forms the afferent nerves of the olfactory nerve?

Answer 26

axons of olfactory receptors

Question 27

Why do we sniff?

Answer 27

To draw air currents upwards within the nasal cavity to enhance smelling and odorant contact with the olfactory receptor cells

Question 28

What are the 2 properties required of a substance to be smelled?

Answer 28

sufficiently volatile and water soluble

Question 29

What is anosmia?

Answer 29

Inability to smell

• may be temporal or permanent
• caused by viral infection, allergy, nasal polyps and head injury

Question 30

What is hyposmia?

What are the causes?

Answer 30

reduced ability to smell

- causes usually the same as anosmia

Question 31

What is the pathway of smell?

Answer 31

Olfactory receptor cells - olfactory bulbs - olfactory tract to temporal lobe and olfactory areas

Question 32

What can hyposmia be an early sign of?

Answer 32

can be an early sign of parkinson’s