Sensory Transduction

Question 1

where do most axons of retinal ganglion cells synapse?

Answer 1

lateral geniculate nucleus

Question 2

how do intrinsically photosensitive retinal ganglion cells (ipRGCs) differ from the other types of photoreceptor cells – rods and cones?

Answer 2

ipRCGCs are able to respond to bright light even w/o input from rods and cones.

• involved in several non-imaging functions of visual system

Question 3

receptive field of ganglion cells at retinal periphery is what compared to fovea (center of retina)?

Answer 3

much larger

Question 4

what is the main response of the outer hair cells to depolarization?

Answer 4

outer hair cells contract, amplifying movement of basilar membrane.

Question 5

what is the main response of inner hair cells to depolarization?

Answer 5

inner hair cells release NTs.

Question 6

under scotopic conditions, human eye is maximally sensitive at

Answer 6

~500 nm

Question 7

under photopic conditions, human eye is maximally sensitive at

Answer 7

~560 nm

Question 8

S cone, M cone, L cone peak at what point?

Answer 8

~420 nm

~530 nm

~560

Question 9

melanopsin peaks at what point of the spectrum?

Answer 9

~475 nm

Question 10

dark adaptation

Answer 10

rods

Question 11

light adaptation

Answer 11

cones

Question 12

a condition that doesn’t have 2 of the 3 functional cone pigments

Answer 12

monochromacy (true color blindness)

Question 13

absence of one functional pigment

Answer 13

dichromacy

Question 14

shift in absorption spectrum of one pigment relative to normal

Answer 14

anomalous trichromacy

Question 15

a light sensitive protein

Answer 15

melanopsin

Question 16

functions of ipRGCs

Answer 16

• plays a role in maintaining circadian rhythm
• activity inhibits production of melatonin by pineal gland
• provides photic info to brain’s sleep-wake regulatory systems
• reports levels of ambient daytime illumination

Question 17

olfactory receptors are _____/

Answer 17

neurons

Question 18

taste receptors are ______.

Answer 18

modified epithelial cells

Question 19

location of foliate papillae

Answer 19

folds along lateral surfaces of tongue

Question 20

location of circumvallate papillae

Answer 20

posterior tongue

Question 21

location of fungiform papillae

Answer 21

flat anterior surface of tongue

Question 22

what kind of receptor cells are replaced throughout life?

Answer 22

olfactory receptor cells

Question 23

how many genes does one olfactory receptor cell express?

Answer 23

only one gene is expressed by each receptor cell

Question 24

function in detecting head rotation

Answer 24

3 semicircular canals

Question 25

detect head position (gravity) and linear head movement

Answer 25

otolithic organs -- utricle, saccule

Question 26

What structures of the ear collect and focus waves into external auditory canal?

Answer 26

pinna/auricle and tragus

Question 27

What connects the middle ear to the nasopharynx??

Answer 27

Eustachian tube

Question 28

What does Eustachian tube do>

Answer 28

equalizes pressure on opposite side of tympanic membrane

Question 29

Function of middle ear (an air filled chamber)

Answer 29

Serves to transfer vibrations of TM to the oval window

Question 30

What is the function of tensor tympani and stapedius?

Answer 30

their contract dampens transfer of sound to inner ear

Question 31

Which fluid filled compartment of cochlea does the air enter?

Answer 31

Scala vestibuli

Question 32

What kind of fluid do scala tympani and scala vestibuli contain?

Answer 32

Perilymph

Question 33

What kind of fluid does scala media contain?

Answer 33

Endolymph

Question 34

What do mechanoreceptors monitor?

Answer 34

- BP in heart - stretching of gut and intestines - skin contact - pressure on teeth

Question 35

What layers of the skin are innervates by sensory receptors?

Answer 35

epidermis, dermis

Question 36

What are 2 specialized types of free nerve endings?

Answer 36

Merkel discs Hair follicle receptors

Question 37

Rapidly adapting receptors

Answer 37

hair follicle receptors

Question 38

slowly adapting receptors for light touch

Answer 38

merkel discs

Question 39

Meissner’s corpuscles

Answer 39

respond to low frequency vibrations and light touch

Question 40

Pacinian corpuscles

Answer 40

respond to deep pressure and high frequency vibrations

Question 41

Ruffini’s corpuscles

Answer 41

slow adapting; respond to skin stretch

Question 42

proprioceptors

Answer 42

detect notion and position of body through a stimulus produced w/in body

Question 43

golgi tendon organ contains what kind of axons ?

Answer 43

Group Ib axons

Question 44

muscle spindle contains what kind of axons?

Answer 44

There are 2. Primary sensory endings - group Ia axons Secondary sensory endings - group II axons

Question 45

What kind of innervation does muscle spindle receive?

Answer 45

afferent and efferent innervation

Question 46

Why do muscle spindles still get motor innervation when their primary function is sensory?

Answer 46

To continue to maintain control over sensitivity of the spindle This is done with the help of gamma motor neurons, which cause intrafusal muscle fibers to contract in parallel w/ extrafusal fibers

Question 47

What do tears have that help fight infection?

Answer 47

lysozymes, antibodies

Question 48

What constantly secretes aqueous humor in the eyes?

Answer 48

ciliary epithelium

Question 49

Aqueous humor

Answer 49

protein free ultrafiltrate of blood plasma

Question 50

What is the importance of keeps the anterior portion of the eye slightly pressurized — ~20mmHg?

Answer 50

helps maintain eye shape

Question 51

When ciliary my muscles are contracted, the lens are?

Answer 51

Rounded for close vision

Question 52

when ciliary muscles are relaxed, lens are ______/

Answer 52

flattened for distant vision