Physiology

Question 1

What kind of receptors are the receptors for taste and smell?

Answer 1

Chemoreceptors

Question 2

Which 2 types of cells do taste buds consist of?

Answer 2

Support cells
Sensory receptor cells
(these are rearranged like the slices of an orange)

Question 3

Which of the following papillae does not contain taste buds?
- foliate, valate, filiform, fungiform

Answer 3

Filliform

Question 4

How often are taste receptor cells replaced?

Answer 4

Every 10 days

Question 5

Name the 5 primary tastes

Answer 5

Salty
Sweet
Sour
Bitter
Umami

Question 6

Salty taste

Answer 6

Stimulated by chemical salts, especially NaCl

Question 7

Sweet taste

Answer 7

Stimulated by configuration of glucose

Question 8

Sour taste

Answer 8

Stimulated by acids which contain free H+ ions

Question 9

Bitter taste

Answer 9

Stimulated by diverse group of tastiest

Question 10

Umami taste (meaty or savoury)

Answer 10

Triggered by amino acids (esp glutamate)

Question 11

Ageusia

Answer 11

Loss of taste function

Question 12

Hypogeusia

Answer 12

Reduced taste function

Question 13

Dysgeusia

Answer 13

Distortion of taste function

Question 14

Cell types present in the olfactory mucosa (3)

Answer 14

Olfactory receptor cells
Supporting cells
Basal cells

Question 15

Basal cells function

Answer 15

Act as precursors for new olfactory receptor cells

Question 16

2 main requirements for a substance to be smelled

Answer 16

Volatile
- some of its molecules can enter the nose with inspired air

Water soluble
- can dissolve in the mucous coating of olfactory mucosa

Question 17

Anosmia

Answer 17

Inability to smell

Question 18

Hyposmia

Answer 18

Reduced ability to smell

Question 19

Dysosmia

Answer 19

Altered sense of smell

Question 20

what is sound?

Answer 20

Pressure wave caused by oscillating molecules

Question 21

Function of external ear

Answer 21

Sound collector

Receives sound and funnels it into ear drum

Question 22

What are the components of the ossicular chain

Answer 22

Malleus
Incue
Stapes
- connected to each other by synovial joints

Question 23

What does the stapes connect on to?

Answer 23

Oval window

Question 24

What happens when pressure waves cause the stapes to vibrate against the oval window?

Answer 24

Vibrations travel up the perilymph (fluid) in the cochlea.

Different thicknesses of basilar membrane vibrate in response to different frequencies of sound

Question 25

Which structure of the inner ear contains receptors for transduction?

Answer 25

Cochlea

Question 26

What is transduction?

Answer 26

Conversion of a mechanical wave into an electrical signal

Question 27

What is the basilar membrane and where is it located?

Answer 27

Mechanical analyser that runs the length of the cochlea, curling towards the cochlea’s centre.
It vibrates in different regions depending on the frequency of the sound waves impinging on it

Question 28

Where do sound waves exit?

Answer 28

Through the round window

Question 29

Where is the site of sound transduction?

Answer 29

Organ of corti

Question 30

What does the organ of corti contain on its surface?

Answer 30

Lots of stereo cilia (which are mechanoreceptors)

Question 31

What happens when stereo cilia hair cells are bent by vibrations?

Answer 31

The hair cell membrane is depolarised and an electrical signal (action potential) is transferred to the cochlear nerve.

Question 32

High frequency sounds vibrate the basilar membrane near the start/near the end

Answer 32

Near the start (near the oval window)

Question 33

Low frequency sounds vibrate the basilar membrane near the start/near the end

Answer 33

Near the ned (travel further along the membrane towards the inner turns)

Question 34

What is the normal range of sound frequency for humans to perceive?

Answer 34

20Hz - 20,000 Hz

Question 35

Balance: what are the 5 vestibular receptor organs in the inner ear that make up the vestibular labyrinth?

Answer 35

Utricle
Saccule
3x semicircular canals

Question 36

Balance: what do stereo cilia project into?

Answer 36

Gelatin (which contains calcium carbonate crystals - otoconia).

Question 37

Balance: what happens to the stereo cilia and gelatine when the head is tilted?

Answer 37

Crystals continue to be pulled straight down by gravity.

The new angle causes the gelatin to shift, thereby bending the cilia

Question 38

Balance: what happens when there is bending of stereo cilia

Answer 38

Stimulation of specific neurones that signal to the brain that the head is tilted, allowing maintenance of balance

Question 39

Balance: semicircular canals function

Answer 39

Detects angular acceleration or decelleration

Question 40

Balance: what happens to the fluid in the semi-circular canals when the head turns?

Answer 40

The fluid in the canals shifts which bends the stereo cilia and sends signals to the brain

Question 41

Balance: the otolith of the utricle and saccule

Answer 41

Viscous gel that contains calcium carbonate crystals

Question 42

Balance: What happens to the otolith when the head is tilted

Answer 42

Moving of the otolith bends the stereo cilia which causes some hair cells to depolarise and others to hyperpolarise

Question 43

Balance: what does the ampulla of the semicircular canals contain?

Answer 43

Hair cells that respond to rational movement

e.g. when turning head from side to side to signal “no”

Question 44

Balance: where in the semicircular canal is the cupula found?

Answer 44

Attaches to the top of the ampulla

Question 45

Balance: What happens to the cupula as the head rotates?

Answer 45

As the head rotates, the cupula bends in the opposite direction of the rotation

Question 46

What is the vestibule-ocular reflex (VOR)

Answer 46

Preserving image on the centre of visual field during head movement by producing eye movement in the opposite direction of head movement

(e.g. when head moves to the right, the eyes move to the left)