Special Sense Organs Flashcards Preview

NBDE PART 1 BIOCHEM/PHYSIOLOGY > Special Sense Organs > Flashcards

Flashcards in Special Sense Organs Deck (73):
1

rods/cones contain rhodopsin-a photopigment

rods = rhodopsin (need Vit A)

2

cones/rods responsible for color vision

cones = color vision

3

rods/cones used for dark adaptation

rods =dark ===> hint look at the letters = r and d

4

rods and cones are located in the

retina

5

which are more abundant: rods or cones

rods

6

the __ is the innermost layer of the eye

retina

7

the __ is the nervous tissue of the eye

retina

8

retina receives visual stimuli and send the info to the brain. Photoreceptor cells called __ and __ compose the visual receptors for the optic nerve of the retina

rods and cones

9

there are 4 different photopigments consisting of a protein called __ to which retinal is attached

opsin

10

opsin differs from pigment to pigment and cnfer specific light sensitive properties on each photopigment. Retinal produced from ___ is added to opsin to make?

vitamin A ==> retinal ==> retinal + opsin = rhodopsin

11

rods contain the photopigment

rhodopsin

12

rods are numerous in the __ of the retina

periphery

13

what are the 3 different types of cones?

red, blue, green (RBG), each contains a different photopigment and is selectively sensitive to diff wavelengths.

14

cones are numerous in the _ of the retina

center of the retina, especially the fovea

15

during dark adaptation (dark vision) rhodopsin is synthesized in the rods. Severe vitamin A deficiency over many months causes

night blindness

16

___ are the principal photoreceptors during daylight or in brightly lit areas

cones

17

Rods are more/less abundant?
Rods are more/less sensitive (than cones)?
more or less acuity?

rods are more abundant, have higher sensitivity and less visual acuity

18

the crystal clear dome that covers the front of the eye is called

cornea

19

the majority of the focusing in the eye is done by the:
lens or the cornea?

cornea! 70% of bending/refracting of light rays occurs here

20

does the shape of the cornea change

no (with the exception of small changes over lifetime)

21

the crystalline ___ finishes the focusing of light after the cornea does the majority.

lens

22

can the lens change shape

yes. it can fine tune vision due to this ability.

23

when the __ becomes cloudy = cataract

lens

24

the opening in the middle of the iris

pupil

25

part of the eye that gives it color

iris

26

this part of the eye acts like a shutter allowing more or less light into the eye

iris

27

this is a thin layer of nerve tissue that senses light. specialized cells called rods and cones convert light energy into nerve signals that travel thru the optic nerve to the brain.

retina
the retina is analogous to film on a camera

28

this is the center of the retina that receives the focus of the object. nerve cells are more densely packed here especially the CONES so images focused here can be seen in greater detail

fovea

29

the is the nerve that runs from the eyeball to the brain. carries info from the retina to the brain for interpretation

optic nerve

30

the eyeball itself is divided into 2 segments each filled with fluid. the anterior segment has how many chambers

2 = anterior and posterior. anterior is between the cornea and the iris and the posterior between iris and lens

31

the anterior chamber (both posterior and anterior) is filed with aqueous or vitreous humor?

anterior is Aqueous humor = watery (think your eyes water/tear in the front, and A is for anterior and aqueous

32

the vitreous humor is thick and gelatinous and located in the __ of the eye

posterior

33

sound waves strike the __ and cause it to vibrate

tympanic membrane

34

vibration of the tympanic membrane causes the oval/round__ to vibrate next

oval window

35

the oval window vibration causes the ____ in the bony labyrinth of the cochlea and the ___ in the membranous labyrinth to move.

perilymph = bony labyrinth
endolymph - membranous labyrinth

36

the movement of the endolymph causes the ___ to vibrate

basilar membrane

37

the movement of the basilar membrane stimulates hair cells on the __ to transmit nerve impulses along the cranial nerve ==> auditory complex = interpreted as sound

organ of Corti

38

external ear made up of

auricle (directs sound waves) aka pinna
external auditory canal (meatus) = contains hair and cerumen (brown earwax), resonates sound

39

the middle ear aka typmpanic cavity is located in the __ bone and is filled with

temporal bone and filled with air

40

middle ear is made of

auditory tube = equalizes pressure
and ossicles (malleus incus stapes) transmit sound to oval window and create a 22 fold amplification of sound from the tympanic membrane to oval window

41

inner ear is formed by

a membranous labyrinth within a bony labyrinth

42

the inner ear is mainly responsible for __ and __.

sound detection and balance.

43

1. vestibular system, is dedicated to__
2. The cochlea, dedicated to ___; converting sound pressure patterns from the outer ear into electrochemical impulses which are passed on to the brain via the auditory nerve.

1. balance
2. hearing

44

The inner ear is innervated by the ___cranial nerve in all vertebrates

VIII = vestibulocochlear nerve

45

The bony labyrinth, or osseous labyrinth, is the network of passages with bony walls lined with periosteum. The membranous labyrinth runs inside of the bony labyrinth. There is a layer of ____ fluid between them

perilymph

46

The vestibular system is the region of the inner ear where the semicircular canals converge, close to the cochlea. The vestibular system works with the___system to keep objects in focus when the head is moving

visual

47

the vestibule is made of __ and is associated with sense of balance

saccule and utricle

48

the semicircular canals are concerned with

equilibrium

49

the cochlea contains 2 membranes: the _ and _

vestibular and basilar.

50

the receptors for hearing are located in the _ and are called

organ of Corti
hair cells

51

the basic functional unit of hearing is the

cochlea = transforms fluid vibrations from sound waves (mechanical energy) into nerve impulses (electrical energy)

52

the tympanic membrane and tympanic cavity, semicircular canals, vestibule, and eustachean tube opening are located in the _ of the ear

middle

53

the cochlea is located in which part of the ear

inner (along with the vestibular and cochlear nerve (CN 8)

54

your patient just came back from an ophthalmology appointment where she received tropicamide to induce mydriasis. how will it affect her dental appointment

patient will be extra sensitive to the overhead dental light

55

miosis is

constriction of the pupil

56

mydriasis is

PROLONGED abnormal dilation of the pupil induced by a drug or disease and causes the eye to become extra sensitive to light

57

myopia

nearsightedness = eye can focus on very near objects.

58

hyperopia

farsightedness

59

in ___ myopia/hyperopia:
the eye is too long for the refractive power of the lens, and far objects are focused at a point IN FRONT OF THE RETINA.

myopia (nearsightedness)

60

myopia is caused by either
1. eye is too __ compared to normal
2. or cornea is __than normal

1. long
2. steeper

to remember: think near sighted, the object is right in front (near) the retina and I cant see far bc im in a cave and the corn is steep

61

to treat myopia what kind of lens would you wear: convex/concave/cylindric

concave

myopia = cornea steep/eye too long/concave lens/far objects are focused in front of the retina
to remember = think near sightedness, so the object focuses more near the object. in far sightedness the object is focused far away from the eye (behind the retina)

62

in ___ myopia/hyperopia:
the light focuses BEHIND THE RETINA

hyperopia

63

in hyperopia:
1. the cornea is __ or the eye is __

cornea is flatter, or eye is shorter (remember in myopia the cornea was steeper or eye was longer)

64

farsighted pp usually have trouble seeing up close but may also have difficulty seeing far away as well. to treat hyperopia what kind of lens?
convex/concave/cylindric

convex

65

___ occurs when the curvature of the lens is not uniform.

astigmatism

66

astigmatism is corrected with which lens
convex/concave/cylindric

cylindric

67

1. myopia lens
2. hyperopia lens
3. astigmatism lens

1. concave
2. convex
3. cylindric

68

mnemonic for myopia and hyperopia

myopia is the "short" word = near sighted
hyperopia is the "long" word = far sighted
My cave" (Myopia - Concave)

69

presbyopia

eye cant focus sharply on nearby objects - bc of loss of elasticity of the lens with advanced aging.

70

presbyopia corrected with

bifocals = to remember just look at the word: presByopia = bifocals - only one with a B

71

what are opsins

Opsins are a group of light-sensitive membrane-bound G protein-coupled receptors found in photoreceptor cells of the retina. opsins are involved in vision, mediating the conversion of a photon of light into an electrochemical signal, the first step in the visual transduction cascade. Another opsin found in the mammalian retina, melanopsin, is involved in circadian rhythms and pupillary reflex but not in image-forming.

72

what is visual purple

another name for Rhodopsin

73

___is a biological pigment in photoreceptor cells of the retina that is responsible for the first events in the perception of light.

Rhodopsins belong to the G-protein-coupled receptor family and are extremely sensitive to light, enabling vision in low-light conditions