Lecture 21 & 22: the eye Flashcards Preview

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Flashcards in Lecture 21 & 22: the eye Deck (55)
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1
Q

define sclera

A

outermost cover of the eye

2
Q

what is the episceral layer of the sclera

A

outer layer
loosely arranged collagen and elastic fibers
highly vascularized
attached the lining of the eyelid (conjunctiva) to sclera

3
Q

what is the sclera proper

A

located in sclera
made of interlacing collagen fibers
attachment site for tendons of extrinsic eye muscles

4
Q

define lamina cribosa

A

perforated disc of sclera

pass through the optic nerve fibers

5
Q

define limbus

A

junction between sclera and cornea

6
Q

what is the posterior of the sclera continuous with

A

dural covering of the optic nerve

7
Q

define cornea

A

anterior continuation of sclera

8
Q

what type of epithelium is in the cornea

A

stratified, nonkeratinized squamous epithelium

9
Q

what is bowmans membrane

A

acellular layer that separates epithelium from stroma

10
Q

what is the corneal stroma

A

thin layers of ordered arrays of collagen fibers

11
Q

what is descements membrane

A

acellular, separates stroma from endothelium

12
Q

what is included in the vascular tunic

A

choroid, ciliary body and iris

13
Q

define choroid

A

extends anterior to ora serrata of retina

14
Q

what forms the choriocapillar network and what is taht

A

choroid

contains small blood vessels that supply cell of retina

15
Q

what is bruchs membrane

A

acellular fused basal laminae of choriocapillaris and pigmented retinal eptithelium

16
Q

define ciliary body

A

wedge-shaped expansion of choroid peripheral to the lens and covered by double layer of cells

17
Q

define iris

A

located anterior to the lens and separates the anterior and posterior chambers and surrounds pupil.

18
Q

what epithelium is in the iris

A

inner layer: pigmented epithelial cells

outer layer: radially oriented myofilaments

19
Q

what is the pigmented ring of the eye

A

iris

20
Q

define the retina

A

photosensitive region that lies posterior to the ora serrata

21
Q

define optic disc

A

region on posterior aspect of eye where optic nerve excises (no photosensitive retina and constitutes blind spot)

22
Q

define fovea centralis

A

area in retina that contains only cone-type photoreceptors

23
Q

what are the chambers of the eye

A

anterior: posterior to cornea and anterior to iris
posterior: posterior to iris and anterior to lens
vitreal: posterior to lens, contains vitreous body

24
Q

where is the pigmented layer of the retina located

A

adjacent to choroid

25
Q

what is the external limiting membrane of the retina

A

area at junction and outer segments of rods and cones and outer layer
includes adherens junctions between rods and cones and mueller cells

26
Q

what is the outer layer of the retina

A

cell bodes of rods and cones (1st order neurons)

27
Q

what is the outer plexiform layer of the retina

A

areas of synapses between axons of rods and cones and dendrites of bipolar neurons and horizontal cells

28
Q

what is the inner nuclear layer of the retina

A

cell bodes of bipolar cells (2nd order neurons), horizontal cells, amacrine cells and mueller cells

29
Q

what is the inner plexiform layer of the retina

A

area of synpases betweens axons of bipolar cells and dendrites of ganglion cells

30
Q

what is the ganglion cell layer of the retina

A

cell bodies of ganglion cells (3rd order neurons)

31
Q

what is the optic nerve layer of the retina

A

axons of ganglion cells

32
Q

what is the internal limiting membrane of the retina

A

terminations of mueller cell processes and their basement membrane (support cells)

33
Q

what are the cells of the retina

A

bipolar, horizontal, amacrine, mueller, ganglion

34
Q

define bipolar cell

A

conducting nuerons that synapse with rods and cones

35
Q

define horizontal cells

A

interneurons that interconnect rods and cones with each other and with bipolar cells

36
Q

define amacrine cells of retina

A

interneurons that connect gangion cells and bipolar neurons

37
Q

define mueller cells

A

neuroglialc cells that extend through the retina and form external limiting membrane via zonulae adherens between mueller cells and rods and cones

38
Q

define ganglion cells

A

conducting neurons whose axons form the fibers of the optic nerve

39
Q

define macula lutea

A

yellow region surrounding fovea, highest visual acuity

40
Q

define fovea centralis

A

depressing of cone cells

41
Q

define optic disc

A

lacks photoreceptors, point where ganglion cells turn into optic nerve (tract)

42
Q

what do rods use as photopigment

A

rhodopsin

43
Q

what do cones use as photopigment

A

iodopsins

44
Q

what are the discs like in rods

A

discs attach from cell membrane and become free

constantly renewed

45
Q

what are discs like in cones

A

discs remain attached to cell membran

46
Q

what type of vision, lamellae, and sensitivity do rods have

A

black and white
not continuous lamellae
sensitive to low intensity lightg

47
Q

what type of vision, sensitivity, and lamellae do cones have

A

color
high intensity sensitivity
continuous lamellae

48
Q

define bleaching

A

disassembly of rhodopsin into opsin and retinal after light stimulation

49
Q

define capsule of lens

A

insertion point for suspensory ligament
glycoproteins and type 4 collagen
secreted by subscapular epithelial cells

50
Q

define the anterior epithelium of the lens

A

simple cuboidal epithelial

gives rise to cells that become lens fibers

51
Q

define the lens nucleus

A

composed of lens cells that mature into fiber like stucture
devoid of nucleus and organelles
filled with crystalline proteins

52
Q

what are the 2 types of glands in anterior surface of the eyelid

A

zeiss: sebaceous glands associated with eyelids
moll: sweat glands, ducts open into eyelash follicles

53
Q

define palpebral fascia

A

fibrous core of eyelids

meobomian glands: secretion keeps normal tear film in eye

54
Q

define palpebral conjunctiva

A

stratified columnar or squamous epithelium with goblet cells
lines inner surface of the eyelids
continuous with bulbar conjunctiva (covers eyeball)

55
Q

what are the 3 tunics of the eye and what are the structures associated with each

A

fibrous: sclera, cornea
vascular: choroid, ciliary body, iris
inner: retina