Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Anatomy 2 > Lect 4 The eye > Flashcards

Lect 4 The eye Flashcards

1
Q

the eye

A

housed in the bony orbit
optic canal at back though which the optic nerve leaves the bony orbit to enter cranial cavity
-specialized for photoreception
-light passes through several structures before encountering light sensitive retina in back of eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 layers of the eye

A

Fibrous tunic
vascular tunic
neural tunic/retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Fibrous tunic

A

outer layer

includes sclera ‘white of eye’; anteriorly, the sclera is continuous with transparent cornea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Vascular tunic

A

middle layer
most of this layer is the choroid, which contains abundant capillaries that supply a portion of the retina
anteriorly, this layer inclueds ciliary body and the iris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Neural tunic/retina

A

inner layer
comprised of retinal pigment epithelium (outer) and neural retina (inner)
Photosensitive retina ends at the ora serrata, but both continue anteriorly and cover the inner layer of ciliary body and iris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Sclera

A

in fibrous tunic
White of the eye
thick layer of dense CT(goes in all directions), mainly Type I collagen with few elastic fibers, some elongated fibroblasts
Sensory innervation
vascularized (few)
Function: serves as protective envelope for internal eye structures; provides attachment site for extraocular eye muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cornea

A 
fibrous tunic
Transparent
avascular - gets nutrients from aqueous humor and lacrimal fluid (includes o2 absorbed from air)
Highly innervated, very sensitive
used in refraction of light to focus
5 histologically distinct layers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Five corneal layers

A
  1. corneal epithelium
  2. bowmans membrane
  3. stroma
  4. descemet’s membrane
  5. corneal endothelium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

conreal epithelium

A

stratified squamous, non keratinized epithelium (5-7 days)
Turnover rate ~7 days (corneal injury)
highly innervated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Bowman’s membrane

A

basement membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

stroma

A

90% of corneal thickness
Abundant type 1 collagen, few elastic and fibroblasts
lamella organization of this layer is important in transparency of cornea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

descemet’s membrane

A

basement membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

corneal endothelium

A

simple squamous layer, lines posterior surface of the cornea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Conjunctiva

A

mucous membrane covering anterior sclera and lines inside of eyelid

  • stratified columnar epithelium which contain goblet cells
  • goblet cell secretions contribute to tear film
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

conjunctivitis

A

clinical note
aka pink eye
inflammation of the conjunctiva. caused by virus or bacteria and easily spread person to person. can become inflamed in response to allergens and irritating substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Choroid

A

posterior portion of vascular tunic
-loose CT
highly vascularized - provides nutrients to retinal pigment epithelium and outer layers of the neural retina (inner layers supplied by central retinal artery
and pigmented)
Pigmented: melanocytes give the choroid its dark appearance. melanocytes function in absorbing light that has passed through the retina. This prevents visual interference from light deflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

ciliary body

A 
vascular tunic
wedge shaped region 
loose CT 
well vascularized w/ smooth muscle
double layer of cuboidal epithelium (1 pigmented and 1 non pigmented=surface layer)
Function: produce aqueous humor
change shape of the lens
18
Q

ciliary body

A

ciliary processes have abundant fenestrated capillaries. plasma filtrate is transported across the epithelium as aqueous humor

19
Q

aqueous humor

A

provides nutrients to lens and cornea
enters posterior chamber -> pupillary aperature -> anterior chamber -> leaves via canal of Schlemm to enter the venous system

20
Q

glaucoma

A

increase intraocular pressure caused by failure of resorption of aqueous humor
-leads to compromised retinal blood flow and progressive retinal damage
can cause blindness if untreated

21
Q

zonule fibers

A

radiate from ciliary body and insert into the lens capsule forming the suspensory ligament of the lens

22
Q

Ciliary muscle activation

A

contraction: reduces tension on zonule fibers and cause lens to buldge, (convex)
allows eye to focus on near objects = accomodation

Relaxation: increases tension on zonule fibers and causes the lens to flatten. this allows the eye to focus on distant objects

23
Q

iris

A

anterior extension of vascular tunic

posterior surface of iris is composed of heavily pigmented cells- block light from passing directly though the iris

24
Q

anterior pigmented cells of iris

A

(and within stroma of iris) impart eye color

dark eyes have high # of pigmented cells

25
Q

smooth muscle in stroma of iris

A

dilator pupillae (radially oriented) and sphincter pupillae (circumferentially oriented) control pupillary aperture

26
Q

lens

A 
biconvex, transparent disc that functions to focus light on retina
3 parts
lens capsule
subcapsular epithelium
lens fibers
27
Q

lens capsule

A

basement membrane, completely envelops the lens

28
Q

subcapsular epithelium

A

single layer of cuboidal cells located only on the anterior surface of lens. at equators, the subcapsular epithelium give rise to lens fibers

29
Q

lens fibers

A

generated at the equator and continue at a very slow rate throughout lilfe. immediately deep to subcap epi. bulk of lens is composed of these 2000-3000 elongated cells. elongate as the mature, lose nuclei and organelles
become filled with proteins called crystallins

30
Q

cataract

A

opaque lens

31
Q

vitreous body

A

transparent, refractile gel that fills the vitreous cavity located behind the lens
composed of 99% water, but contains collagen and hyaluronic acid

32
Q

hyalocytes

A

at periphery of vitreous body
believed to synthesize collagen and hyaluronic acid
Phagocytic cells are also reportedly present at low numbers

33
Q

retina

A

direction of light opposes direction of info flow to optic nerve

34
Q

retinal pigment epithelium

A

RPE
cuboidal to columnar cells w/ basally located nuclei
Apical aspect have abundant melanin granules, microvilli and sleeve like extensions that surrounds tips of photoreceptor cells
Function: reduces light scatter by absorbing stray light & phagocytose membrane shed from photoreceptors
desmosomes, zonulae occludens and zonulae adherents present and form blood retina barrier

35
Q

Anatomy layer of retinal

A

Top

  1. inner limiting membrane
  2. ganglion cell axons
  3. cell body of ganglions
  4. inner plexiform synaptic layer
  5. inner nuclear layer (bipolar cell bodies, amacrine cells)
  6. outer plexiform synaptic zone
  7. outer nuclear layer (cell bodies of rods and cones)
  8. outer limiting membrane
  9. photoreceptor layer (rods and cones)
  10. retinal pigment epithelium
36
Q

photoreceptors

A

absorb photons -> receptor potential, info is processed through retinal layers before reaching retinal ganglion cells
rods vs cones

37
Q

Rods

A

extremely sensitive to light and are used at night

monochromatic: all rods have same rhodopsin

38
Q

cones

A

sensitive in daylight, require higher intensity of light compared to rods
trichromatic=3 opsins for different wavelengths
relative activity of different opsins can be interpreted as color

39
Q

colorblindness

A

altered gene expression of one or more cone opsins
red-green color blindness affects 2% males
often occur together because of the proximity of these genes on the X chromosome

40
Q

fovea

A

specialized feature of retina
region for high acuity vision
particulary rich in cones
several of the retinal layer are absent at the fovea so that the light does not have to traverse these layers, instead these retinal layers are positioned at the edges of the fovea

41
Q

Optic disk

A

exit point of the retinal ganglion cell axons
-unmyelinated retinal ganglion cell axons collect here, pierce sclera, acquire myelin sheath and form the optic nerve
No photoreceptors at the optic disk so we are blind to any image that falls on this part
no awareness to this blindspot as we walk around

Anatomy 2 (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions