Retinal Physiology Flashcards

1
Q

which three layers make the eye tissue? [3]

  • outer layer: [2] (front and back?)
  • middle layer: [1]

- inner laye: [1]

A

which three layers make the eye tissue? [3]

  • outer layer: sclera (back); cornea (front)
  • middle layer: uvea

- inner laye: retina

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2
Q

which of the following is the iris?

A
B
C
D
E
F

A

which of the following is the iris?

A
B
C
D
E
F

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3
Q

which of the following is the uvea?

A
B
C
D
E
F

A

which of the following is the uvea?

A
B
C
D
E
F

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4
Q

which of the following is the choroid?

A
B
C
D
E
F

A

which of the following is the choroid?

A
B
C
D
E
F

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5
Q

which of the following is the ciliary body?

A
B
C
D
E
F

A

which of the following is the ciliary body?

A
B
C
D
E
F

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6
Q

which of the following is the retina?

A
B
C
D
E
F

A

which of the following is the retina?

A
B
C
D
E
F

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7
Q

which of the following is the cornea?

A
B
C
D
E
F

A

which of the following is the cornea?

A
B
C
D
E
F

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8
Q

which part of the eye is the light sensing organ?

choroid
uvea
retina
sclera
iris

A

which part of the eye is the light sensing organ?

choroid
uvea
retina
sclera
iris

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9
Q

what is the name for the clear bulging surface in front of the eye? [1]

where does it recieve its nutrition from? [1]
whats the nerve supply like? [1]

A

what is the name for the clear bulging surface in front of the eye? [1]
cornea

where does it recieve its nutrition from? [1]
aqueous humour diffusion (its avasucular) BUT: richly supplied with nerve fibres

function? [2]
the main focussing surface of the eye: where the refractive index of the medium changes from air to transparent tissue !

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10
Q

what keeps the cornea’s shape? [1]

A

what keeps the cornea’s shape? [1]
intraocular pressure

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11
Q

what is the name for the white of the eye? [1]

what is the name for the pigmented bit of eye? [1]

A

what is the name for the white of the eye? [1]
sclera (although interior: brown & grooved)

what is the name for the pigmented bit of eye? [1]
iris

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12
Q

what is the conjunctiva? [1]

what type of cells make up the conjuctiva? [1]

function? [1]

A

what is the conjunctiva? [1]
layer

what type of cells make up the conjuctiva? [1]
stratified columnar epithelium; goblet cells

​function? [2]
mucous secreted: mixes with tears to make more viscous
covers sclera & inside of eyelids

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13
Q

which part of the eye contrains pigment epithelial cells which prevent light scattering and reflection & sits inbetween the sclera and the retina?

iris
choroid
cornea
ciliary body
lens

A

which part of the eye contrains pigment epithelial cells which prevent light scattering and reflection & sits inbetween the sclera and the retina?

iris
choroid
cornea
ciliary body
lens

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14
Q

which part of the eye contains smooth muscle bundles which shapes the lens?

iris
choroid
cornea
ciliary body
lens

A

which part of the eye contains smooth muscle bundles which shapes the lens?

iris
choroid
cornea
ciliary body
lens

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15
Q

what is the role of the lens? [1]

how is the shape of the lens changed? [1]

what shape is the lens for:

a) close images?
b) distant images?

A

what is the role of the lens? [1]
- allows eye to focus on objects at various distances

how is the shape of the lens changed? [1]
- ciliary muscles contract / relax

a) close images: bulges
b) distant images: flat

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16
Q

where are the interneurons and ganglion cells which make up the optic nerve found in the eye? [1]

A

where are the interneurons and ganglion cells which make up the optic nerve found in the eye? [1]
retina

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17
Q

what is the fovea? [1]

A

what is the fovea? [1]
centre of the retina: where visual acuity (sensitivty) is highest

18
Q

what is the blind spot? [1]

A

blind spot: place where visual axons leave the eye to form the optic nerve, so there are no photoreceptors here

19
Q

what are the two types of photoreceptors? [2]

which of ^ do you only find in the fovea? [1]

which of ^ are more active in dark? [1]

A

what are the two types of photoreceptors? [2]
rods & cones (red, blue, green)

which of ^ do you only find in the fovea? [1]
cones

which of ^ are more active in dark? [1]
rods

20
Q

describe the structre of rods & cones

A

outer segment: **photoreceptive part

i) rods contain photopigment called rhodopsin
ii) cones contain photopigment called cone opsins**
* *occur in stacked plates**

inner segment: cell body (& mito)

21
Q

why are rods & cones have stacked free floating discs? [1]

why do eyes require high amounts of oxygen? [1]

A

why are rods & cones have stacked free floating discs? [1]
maximises the chance of a photon interacting with a molecule of photopigment

why do eyes require high amounts of oxygen? [1]
one of most metabolically active cells in the body

22
Q

what happens to photoreceptors in the dark? [2]

what happens to photoreceptors in the light? [1]

A

what happens to photoreceptors in the dark? [1]
constant inward leak of sodium in outerpart of the receptor: keeps the cell depolarised. causes the release of glutamate from its synaptic ending

what happens to photoreceptors in the light? [1]
light hyperpolarises the tonic glutamate release

23
Q

how does photorecption in rods occur? [3]

A
  • absorbtion of light causes a confirmational change in shape of rhodopsin
  • changed rhodopsin then acts via a G-protein to reduced the level of cyclic GMP in the rod
  • reduced cyclin GMP: closes sodium channel, cell can repolarise & stop release of glutamate
24
Q

how does photoreception in cones occur? VIA WHAT?

A
  • contain opsins that absorb light at different wavelengths
  • classes of opsins react to different ranges of light frequency: give **colour perception

signal transduction pathway v similar in rods & cones

BOTH DARK DETECTORS**

25
Q

after photoreception has occured, how does signal transduction occur?

A

light passes through the & meets intercalated discs of rods and cones: glutamate is continously released from synaptic endings of rods and cones onto bipolar cells in the dark

this release is supressed by light

bipolar cells then depolarise & release NTs onto ganglion cells

ganglion cells project their axons into the optic nerve and therefore signal this light sensation to the brain

26
Q

which 3 cells cause seeing stuff x

A
  • *photorceptors** (rods & cones - recive light signal & lose inhibitions) that connect to
  • *bipolar cells** that connect to
  • *ganglion cels** that send axons to optic nerve
27
Q

blood supply to eye:

  • inner retina is supplied by the X artery?
  • photoreceptors are supplied by choriod, a network of capillaries supplied by the X arteries? [1]
A

blood supply to eye:

  • inner retina is supplied by the X artery? [1]
  • *central retina artery**
  • photoreceptors are supplied by choriod, a network of capillaries supplied by the X arteries? [1]
  • *cilary arteries

cope for demands of the photoreceptors for oxygen means the retina has DUAL blood supply**

28
Q

how is oxygen provided to photoreceptors? [1

what else is transported away in the blood supply to the photoreceptors? [1]

A

how is oxygen provided to photoreceptors? [1]

oxyen diffuses into photoreceptors from choroid capillaires, through the layer of cells called: pigment epithelium

what else is transported away in the blood supply to the photoreceptors? [1]

**old & worn out membranes is constantly being shed at the distal tip of the rods / cones

epithelial cells phagocytose the worn-out ends of the photoreceptors and transfer the debris in the capillaries of the choroid**

29
Q
A
30
Q

which of the following is the lacrimal artery?

A
B
C
D

A

which of the following is the lacrimal artery?

A
B
C
D

31
Q

which of the following is the ciliary arteries?

A
B
C
​D

A

which of the following is the ciliary arteries?

A
B
C
​D

32
Q

which of the following is the central retinal artery?

A
B
C
​D

A

which of the following is the central retinal artery?

A
B
C
​D

33
Q

which of the following is the opthalmalic artery?

A
B
C
​D

A

which of the following is the opthalmalic artery?

A
B
C
​D

34
Q

which CN causes the secretion of lacrimal gland?

optic nerve
trigeminal nerve
oculomotor nerve
facial nerve
vagus nerve

A

which CN causes the secretion of lacrimal gland?

optic nerve
trigeminal nerve
oculomotor nerve
facial nerve
vagus nerve

35
Q

where do tears enter [1] & exit [1] the eye?

A

where do tears

enter [1]:
excretory ducts of lacrimal gland

& exit [1]
lacrimal punctum -> drains into lacrimal punctum

the eye?

36
Q

parasympathetic efferents to the lacrimal glands synpase at the X ganglion? [1]

A

pterygopalatine ganglion

37
Q

where is aq. humour made? [1]
where does the aqueous humour of the eye drain into? [1]
what creates intraocular pressure? [1]

A

where is aq. humour made? [1]
ciliary body (posterior chamber)

where does the aqueous humour of the eye drain into? [1]
canal of Schlemm

what creates intraocular pressure? [1]
caused by the difference in production / draining of aw humour

38
Q

what is glaucoma? [1]

what raises risk factor of glaucoma? [lots]

A

what is glaucoma? [1]

drainage of fluid into canal of schlemm is blocked: raises pressure and damges the retina

what raises risk factor of glaucoma? [lots]
over 40
family history

African, hispanic, asian
far / near sighted
eye injury
diabetes

39
Q

what are the two subtypes of glaucoma?

how doe drug treatments for glaucoma work?

how do u treat? [5]

A

open angle glaucoma / type 1: slowly progressive condition. trabecular meshwork becomes gradually blocked. normal angle betweeen cornea and iris

primary angle close glaucoma: occurs when angle between cornea & iris is reduced. flow cannot go into canal of schlemm = rapid increase in pressure. sudden pain and visio n loss

40
Q

what is cataracts caused by?

A

light catalyses the formation of free radicals -> damages the lens (esp. cuz light is focussed within here)

if levels of antioxidants is reduced in the aq. humour: lens becomes opaque: cataract

41
Q
A
42
Q

where are most photoreceptors found in the eye? [1]

* which bit of blood circulation can you see in eye using opthalmoscope? [1] *

A

where are most photoreceptors found in the eye? [1]
fovea

* which bit of blood circulation can you see in eye using opthalmoscope? [1] *
inner circulation