5: Physiology of taste and smell

Question 1

What are the receptors for taste and smell?

Answer 1

Chemoreceptors

Question 2

In general, how do poisons taste and smell?

Answer 2

Bad

to encourage you not to ingest it

Acids taste SOUR

Toxins taste BITTER

Question 3

What are the sensory organs of taste?

Answer 3

Taste buds

Question 4

What are the chemoreceptors found in taste buds?

Answer 4

Taste receptor cells

Question 5

Taste receptor cells have a short life span of ___ days.

Answer 5

10

Question 6

Which type of nerve fibres are found in the sensory receptor cells of the taste buds?

Answer 6

Afferent nerves

Question 7

Where are the taste buds found?

Answer 7

Tongue

Palate

Epiglottis

Pharynx

Question 8

Which tongue papillae have taste buds?

Answer 8

Fungiform (anterior), vallate (border) and foliate (fringes)

Filiform (middle) DO NOT

Question 9

Which cranial nerve supplies taste for the

anterior 2/3rds

posterior 1/3rd

of tongue?

Answer 9

Chorda tympani branch of CN VII

CN IX

Question 10

What change in potential does the binding of chemicals to taste buds cause?

Answer 10

Depolarisation

Question 11

Which nerve fibres are action potentials transferred to in the taste buds?

Answer 11

Afferent nerves

Question 12

Which cranial nerve supplies the taste buds of the epiglottis and pharynx?

Answer 12

CN X

Question 13

Which chemical causes a salty taste?

Answer 13

Sodium chloride (NaCl)

Question 14

Which ions cause a sour taste?

Answer 14

Hydrogen ions

i.e acidic

Question 15

Which chemical causes a sweet taste?

Answer 15

Glucose

Question 16

What broad group of chemicals cause a bitter taste?

Answer 16

Toxins

Question 17

What is ageusia?

Answer 17

Loss of taste

Question 18

What is hypogeusia?

Answer 18

Reduced taste

Question 19

What is dysgeusia?

Answer 19

Distorted taste

Question 20

What is gustation?

Answer 20

Taste

Question 21

What is olfaction?

Answer 21

Sense of smell

Question 22

What mucosa of the nasal cavity is important in the sense of smell?

Answer 22

Olfactory mucosa

Question 23

Which cells in the olfactory mucosa act as chemoreceptors?

What kind of nerve fibres do they contain?

Answer 23

Olfactory receptor cells

Afferent fibres

Question 24

From which structures of the olfactory neurons do cilia project outwards?

Answer 24

Olfactory rods

Question 25

Where do **odorants** bind?

Answer 25

**Cilia**

Question 26

Which cells act as **precursors** for new olfactory receptor cells?

Answer 26

**Basal cells**

Question 27

Through which structure do the olfactory nerves pass into the anterior cranial fossa?

Answer 27

**Cribriform plate of ethmoid bone**

Question 28

Which structures do the olfactory nerves become when they pass through the cribriform plate?

Answer 28

**Olfactory bulbs**

Question 29

Which lobe contains the olfactory centre of the brain?

Answer 29

**Temporal lobe**

Question 30

What act enhances the sense of smell by forcing odorants **upwards** onto the olfactory mucosa?

Answer 30

**Sniffing**

Question 31

What two properties must a substance have to be smellable?

Answer 31

**Volatile** (to be carried in the air) **Water soluble** (to dissolve in the mucus that the cilia create)

Question 32

What is **anosmia**?

Answer 32

**Inability to smell**

Question 33

What is **hyposmia**?

Answer 33

**Reduced ability to smell**

Question 34

What is **dysosmia**?

Answer 34

**Altered sense of smell**