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Anatomy and Physio Final > Retinal Blood Flow > Flashcards

Retinal Blood Flow Flashcards

1
Q

The central retinal artery enters the optic nerve about ______mm behind the globe

A

10 - 12mm

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2
Q

The CRA supplies the ______

A

optic nerve and pia mater

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3
Q

What nerve plexus surrounds the CRA?

A

the nerve of Tiedemann

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4
Q

The central retinal circulation must be sparse and thin because _________

A

it is in front of the light path

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5
Q

What supplies the ganglion and bipolar cells?

A

the CRC

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6
Q

What are the three aspects of the central retinal circulation?

A

A. CRA and CRV
B. Capillaries
C. Radial peripapillary circulation

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7
Q

The arteries and veins are within the ______ layer, while the capillary system forms a double layered system in most of the ______

A

The arteries and veins are within the nerve fiber layer layer, while the capillary system forms a double layered system in most of the outer retina

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8
Q

the Retinal Capillary Networks supply every part of the retina except for _____, _____, and ______

A

outer nuclear layer, photoreceptors and RPE

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9
Q

Define scotoma

A

blind spot

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10
Q

_____ serves an area between 10 and 20 degrees out from the macula. the first area where cotton wool spots appear and produces Bjerrum’s scotomas in Glaucoma

A

Radial Peripapillary capillary system

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11
Q

What are the three aspects of the Choroidal Supply?

A

A. SPCA
B. LPCA
C. Cilioretinal artery

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12
Q

Cilioretinal arteries are only in ___% of the population

A

25%

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13
Q

The anterior ciliary arteries follow the ______

A

rectus muscles

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14
Q

2 anterior ciliary arteries arise from each of the rectus muscles except for the _______

A

lateral rectus muscle

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15
Q

The _______ supplies the oxygen and nutrient need of the outermost layers of the retina

A

Choroid

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16
Q

What is the biggest and widest circulation in the body?

A

Choroidal circulation

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17
Q

the _____ is the ONLY blood supply to the macula

A

Choroidal circulation

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18
Q

Regarding speed, the CRC is ____ while the choroidal circulation is ____

A

CRC - slow

choroic - fast

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19
Q

What three layers does the choroid supply?

A

outer nuclear layer
POS
RPE

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20
Q

The paraoptic region of the SPCA supplies the _____ while the distal region supplies the _____

A

paraoptic - Optic nerve head, peripapillary choroid, circule of Zinn/Haller
distal - Choroid

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21
Q

Each sector of the______ fit together like pieces of a jigsaw puzzle. each terminal choroidal arteriole supplies a ____ of the chorriocapillaris

A

Each sector of the distal SPCA fit together like pieces of a jigsaw puzzle. each terminal choroidal arteriole supplies a lobule of the chorriocapillaris

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22
Q

The branches of the ______ pierce the slcera lateral, medial, or infrequently superior to the optic nerve

A

LPCA

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23
Q

To keep the choroid from scarring, if one _____ is destroyed by disease, the others will remain in tact

A

lobule

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24
Q

In the posterior pole, the _______ is arranged in a lobular fashion with alternating feeding arterioles and draining venules

A

choriocapillaris

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25
Q

The ______ lobule does not have its own blood supply

A

Central

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26
Q

what is a watershed zone?

A

the border between the territories of distribution of any two end arteries. Poor vascularity.

27
Q

The part of the optic nerve head that is located in the watershed zone is most vulnerable to _____

A

ischemia

28
Q

_______ is a loss of a lobule and occurs in a matter of minutes. Irreversible within hours to days.

A

Choroidal occlusion

29
Q

The Optic Nerve Head Circulation (ONHC) is comprised from the _______

A

SPCA

30
Q

What are the four parts of the Optic Nerve Head circulation

A
  1. Superficial nerve fiber layer
  2. Pre-lamina
  3. Lamina
  4. Retro-lamina
31
Q

The pre-lamina is supplied by the ______

A

SPCA

32
Q

The _____ is a collagenous plate through which the nerve fibers run on their way out of the globe

A

Lamina (lamina cribosa)

33
Q

The inner part of the retro-lamina is supplied by the _____ while the outer part is supplied by the ______

A

CRA

pial plexus

34
Q

A ________ hemorrhage has a round appearance and is an indication the bleeding has occured in the deep capillary plexus. Cells are oriented _____ in the inner nuclear layer. usually binocular

A

Dot and blot hemorrhage. Cells oriented vertically.

35
Q

A _______ hemorrhage has a wide, uneven appearance. Is an indication that bleeding has occured in the radial peripapillary capillaries. The cells here are oriented ______ in the nerve fiber layer. Usually binocular, but can be monocular in ________.

A

Flame-shaped hemorrhage. Cells oriented horizontally. Monocular in central retinal vein occlusion.

36
Q

A _______ hemorrhage is in the viteous. Typically due to _______ which makes the borders indistinct.

A

Pre-retinal hemorrhage. Due to neovascularization.

37
Q

A ________ hemorrhage arises from beneath the RPE. May be caused by ______ disease.

A

Subretinal hemorrhage. Can be caused by Coat’s disease.

38
Q

A ________ hemorrhage occurs beneath the RPE. A choroidal rather than retinal disease. Disappears with _____ filter on Opthalmoscope

A

Choroidal hemorrhage. Disappears with green filter.

39
Q

_______ is a very rare condition where there is abnormal development in the blood vessels behind the retina. Blood leaks out of the retinal capillaries, which may _______. Usually in _____ and almost always unilateral.

A

Coat’s disease. May detach the retina. Usually in males.

40
Q

_______ is a result of ganglion cell death due to loss of oxygen. Cotton wool spots will appear. Immediate VA drop. Fast, painless, acute.

A

Central Retinal Artery Occlusion. Eventually revascularizes the retina, but the ONH is white… because the ganglion cells are dead.

41
Q

________ involved a blockage of blood outflow. TMP increases and blood is pushed into the retina. VA may be 20/20 if _________.

A

Central Retinal Vein Occlusion. VA may be 20/20 if there is no fluid in the macula.

42
Q

As resistance to flow increases, the perfusion pressure ______

A

decreases

43
Q

Poiseuille’s law

A

Blood flow in a vessel occurs if there is a pressure gradient between two points within the vessel

44
Q

What is autoregulation?

A

the ability of a system to self-regulate its blood flow so that when the transmural pressure increases, the vessels will dilate to maintain the amount of blood flow.

45
Q

Perfusion pressure is equal to ____ - _____

A

Pressure of artery - pressure of vein

46
Q

Defective autoregulation leads to _____

A

ischemic damage

47
Q

The eye contains the only circulation system in the body that has an opposing pressure, the _____working against it

A

IOP

48
Q

Transmural pressure is nearly zero in the eye because why?

A

the IOP and venous pressure are very similar

49
Q

What is transmural pressure (TMP)?

A

the pressure inside the vein compared to the pressure outside the vein.

50
Q

Every circulation system in the eye is autoregulated except for the _________

A

choroidal circulation

51
Q

Lack of autoregulation in the choroid is compensated for by increased extraction of ______ with the slower blood flow as the IOP rises

A

metabolites

52
Q

Because of autoregulation, blood flow does not begin to fall until IOP reaches _______

A

40 mmHg

53
Q

True/False. venous pressure is always higher than the IOP.

A

FUCK YEEEEEAAAAAHHHHHHH VENOUS PRESSURE

54
Q

the retinal venous pressure at the point where the central retinal vein leaves the eye is called the _____

A

ouflow pressure

55
Q

In the retrolaminar space, the pressure is controlled by the _______

A

cerebrospinal fluid

56
Q

Spontanous venous pulsation is found in ____% of normal subjects and occurs in people with CSF pressure below ____ mmHG

A

90% of normal subjects. Occurs with CSF pressure below 190 mmHG

57
Q

True/False. Normal SVP indicates that CSF pressure is normal.

A

FALSEEEEEE FUCK YOU FOR THINKING TRUE

58
Q

What are the three types of open angle glaucoma?

A
  1. Primary open angle glaucoma
  2. Low tension glaucoma
  3. Ocular hypertension
59
Q

True/False. Elevated IOP is the cause of glaucoma

A

FALSE AS FUCK. IOP is simply a risk factor. You’d be better off using age as a predictor.

60
Q

What is a transient ischemic attack?

A

Perfussion pressure decreases, resulting in a loss of blood flow, which results in a transient loss of vision

61
Q

Transient Ischemic Attacks are generally caused by _______. If vision is lost, patient will probably experience _______

A

TIA generally caused by occlusion of carotid artery. If vision is lost, patient will probably have a stroke within the year

62
Q

Pilots typically experience this due to the high amount of pressure they experience at high gravitational forces.

A

Transient ischemic attack. Loss of vision is described as a “curtain falling or rising”

63
Q

Increased resistance in blood flow can be seen in ______ due to an increased _______

A

sickle cell anemia. Increases blood viscosity.

Anatomy and Physio Final (9 decks)

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