Special Senses

Question 1

Olfactory receptor cells do what?

Answer 1

They detect odors

Question 2

Supporting cells

Answer 2

sustain receptors

Question 3

basal cells

Answer 3

Replace olfactory cells every 40-60 days

Question 4

Lamina Propia

Answer 4

• Areolar connective tissue lay

- Houses Blood vessels, nerves and olfactory glands

Question 5

Olfactory bowman glands

Answer 5

Help form mucous covering olfactory epithelium

Question 6

Are olfactory receptor cells, Bipolar? Unipolar? or multipolar?

Answer 6

They are bipolar structure- single dendrite and unmyelinated axon

Question 7

Where are chemoreceptors for a specific odorant housed

Answer 7

They are housed in the olfactory hairs- cilia projecting from receptor cell dendrite

Question 8

What is the pathway of detecting smells

Answer 8

Mucous contains odorant-binding proteins——->odorant binds to protein——->protein stimulates receptor cells——>G-protein in receptor cell actiates adenylate cyclase & converts ATP to cAMP——-> cAMP leads to opening of ion channels for Na+, Ca2+ (depolarization)——> This triggers an action potential conducted to glomerulus

Question 9

Secondary neurons carry signals of smell to what parts of the brain

Answer 9

1. Cerebral cortex (perceive, and identify smell)
2. Hypothalamus (visceral reaction to smell)
3. amygdala (smell recognition, emotional reaction)

Question 10

What is Gustation

Answer 10

The sense of taste

Question 11

What are the four papillae of the tongue

Answer 11

1. Filiform papillae
2. Fungiform Papillae
3. Vallate Papillae
4. Foliate Papillae

Question 12

short and spiked
No taste buds (no role in gustation); help manipulate food
Located on anterior two-thirds of tongue surface refers to what papillae of the tongue?

Answer 12

Filiform papillae

Question 13

mushroom-shaped
Each contains a few taste buds
Located on tip and sides of tongue

Answer 13

Fungiform papillae

Question 14

largest, least numerous
Contain most of the taste buds
Located in a row of 10–12 along posterior dorsal tongue surface

Answer 14

Vallate papillae

Question 15

leaflike ridges
Not well developed
House a few taste buds in early childhood
Located on posterior lateral ton

Answer 15

Foliate papillae

Question 16

How long do chemoreceptive receptor cells of taste buds usually live

Answer 16

7-9days

Question 17

what are the 5 basic taste sensations

Answer 17

1. Sweet
2. salt
3. sour
4. bitter
5. umani

Question 18

What produces the “salt” taste

Answer 18

Produced by metal ions Na+ and K+

Question 19

What produces the “Bitter” taste

Answer 19

Produced by alkaloids (unsweetened chocolate)

Question 20

What produces the “umami” taste

Answer 20

This taste is related to amino acids producing meaty flavor

Question 21

pathway for sweet, bitter and umami taste

Answer 21

1. Tastant binds to specific cell membrane receptors
2. G protein is activated causing formation of 2nd messenger
3. Results in cell depolarization

Question 22

Are the tastants for salt and sour molecules or ions?

Answer 22

Tastants for salt and sour are ions and depolarize the cell directly

Question 23

What do depolarized gustatory cells release and what do they stimulate

Answer 23

1. The release the neurotransmitter stimulating primary neuron in CN VII or CN IX

Question 24

Two common defects of image formation

Answer 24

1. Hyperopia- farsightedness

2. Myopia-near sightedness

Question 25

What could be a result of weak extrinsic eye muscles

Answer 25

This can cause diplopia (double vision) Extrinsic eye muscles are used in the convergence of the eyes

Question 26

Describe the three actions involved in looking at objects of a distance greater than 20ft

Answer 26

1. Eyes face forward (not converged) 2. Lens is Flattened 3. Pupil is relatively dilated

Question 27

What are photopigments

Answer 27

These are light absorbing molecules

Question 28

What are photopigments made of and do they all transduce the same wavelength?

Answer 28

They made of OPSIN protein and light absorbing retinal (made from vitamin A). They do not transduce the same wavelength. Different pigment types have different opsins transducing different wavelengths

Question 29

Do photoreceptors contain multiple photopigments or just one

Answer 29

1. just one Each photoreceptor has only one photopigment type

Question 30

What do Rods contain?

Answer 30

Rods contain Rhodopsin

Question 31

What are the three different types of cones and what kind of wavelength do they detect?

Answer 31

1. Blue cones- Short wavelengths 2. Green cones- intermediate wavelengths 3. Red cones- best detect long wavelengths

Question 32

Know the bleaching reaction and regeneration of rhodopsin

Answer 32

Refer to slides 23 and 24

Question 33

Describe Dark adaptation

Answer 33

- Return of sensitivity to low light levels after bright light - Bleached rods must regenerate rhodopsin - May take 20 to 30 minutes to see well

Question 34

Describe Light adaptation

Answer 34

- Process of adjusting from low light to bright conditions - Pupils constrict, but cones initially overstimulated - Takes about 5 to 10 minutes for full adjustment

Question 35

Sound wave to never signal pathway

Answer 35

1. Sound waves vibrate tympanic membrane 2. Ossicles vibrate and transmit waves to oval window 3. Fluid pressure waves in scala vestibuli push vestibular membrane causing pressure waves in endolymph of cochlear duct 4. Specific regions of basilar membrane move (depending on sound wave frequency) 5. Hair cells distorted, causing changes in neurotransmitter release 6. Sensory neurons with axons in CN VIII are stimulated to fire 7. Pressure is transmitted to scala tympani and absorbed by round window

Question 36

Describe the stimulation pathway of the cochlear hair cell

Answer 36

1. Inner hair cells contain ion channels at their tips and tip link proteins that connect them 2. Hair cells are bathed in K+ endolymph that is far more positive than the fluid inside the cell 3. When basilar membrane moves up, hair cells are pushed into tectorial membrane and their tips are tilted, pulling tip links 4. Tip links pull open ion channel allowing K+ to diffuse into the hair cell and depolarize it 5. Hair cell releases more neurotransmitter from its base, exciting the sensory neuron, which can fire action potentials 6. When basilar membrane moves down, the process quickly reverses

Question 37

What does loudness depend on?

Answer 37

Loudness depends on wave amplitude - louder sounds create larger movements of basilar membrane - the larger the movement the faster the nerve signal and larger number of stimulated cells

Question 38

What creates the perception of sound

Answer 38

This is created by pressure waves vibrating objects

Question 39

What is Pitch dependent on?

Answer 39

Dependent on the frequency of the vibrating object -humans can hear 20-20,000 Hz

Question 40

What do high frequency sounds excite? what do low frequency sounds excite?

Answer 40

High frequency excites cells in stiff basilar membrane Low frequency sounds excite cells in flexible basilar membrane near apex This creates variations in Pitch

Question 41

What monitors our equilibrium

Answer 41

Equilibrium is monitored by vestibular apparatus: utricle, saccule, semicircular ducts

Question 42

What do the Utricle and Saccule detect?

Answer 42

Static equilibrium and linear acceleration

Question 43

What does the semi circular duct detect

Answer 43

angular acceleration