Lecture 6: Choroid Flashcards

1
Q

the choroid is what layer of the eye?

A

The vascular layer of the eye (tunica vasculosa)

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2
Q

what color is the choroid and why?

A

Dark brownish color due to melanocytes

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3
Q

what is the choroid composed of?

A

blood vessels, melanocytes, and connective tissues

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4
Q

the choroid is firmly attached to what 3 locations?

A
  • Scleral spur
  • Exit of vortex veins
  • Optic nerve
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5
Q

The Vascular layer is composed of three structures; what are they?

A
  • iris (anteriorly)
  • ciliary body
  • choroid (posteriorly)
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6
Q

what three structures form a continuous tract?

A
  • iris (anteriorly)
  • ciliary body
  • choroid (posteriorly)
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7
Q

the choroid is the posterior aspect of what?

A
  • posterior aspect of the uveal tract
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8
Q

what does the choroid contain?

A

Contains blood vessels, melanocytes, connective tissue, & mucinous extracellular fluid

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9
Q

what is the primary function of the choroid?

A

Nourishes outer layers of the retina

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10
Q

what is the secondary function of the choroid?

A

Serves as a heat exchange

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11
Q

what structure accounts for 85% of the blood flowing through the eye?

A

choroid

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12
Q

list the choroid layers from inner to outer.

A
  • Bruch’s membrane
  • Choriocapillaris
    (Capillary layer)
  • Choroidal Stroma
    (Vessel layer)
  • Suprachoroid lamina
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13
Q

where is the choroid located?

A

Located between sclera and retina

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14
Q

where does the choroid extend?

A

Extending from ora Serrata to optic nerve

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15
Q

where is the thickest and thinnest part of the choroid?

A

Thickest 0.2mm at the posterior pole

Thinnest 0.1mm at ora Serrata

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16
Q

Suprachoroid lamina has a potential space between what?

A

Potential space between the sclera and choroidal vessels

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17
Q

what does the Suprachoroid lamina contain?

A

Contains collagen bands, fibroblast and melanocytes

18
Q

what causes the Suprachoroid lamina to detach?

A

Can swell without causing detachment

19
Q

what does the Suprachoroid lamina carry?

A

Carry LPCA and LPCN from posterior to anterior

20
Q

Choroidal stroma

A

Pigmented vascularized, loose CT layer

21
Q

what does the Choroidal stroma contain?

A

containing melanocytes,

fibroblasts, macrophages, lymphocytes, and mast cells

22
Q

(Choroidal stroma) Haller’s layer:

A

outer with large lumina vessels

23
Q

(Choroidal stroma) Sattler’s layer:

A

medium-sized vessels

24
Q

what do the venules in the Choroidal stroma join to become?

A

The venules join to become four large vortex veins

25
Q

Clinical relevance: Choroidal stroma

A

Clinical relevance: high density of melanin granules àpotential for choroidal melanoma
(can not miss in the clinic!!!)

26
Q

Choriocapillaris:

A

Specialized capillary bed, a single layer of anastomosed, fenestrated
capillaries with wide lumina

27
Q

where are Choriocapillaris densest?

A

macula

28
Q

what is a unique structure to the choroid and what does it provide?

A

pericytes (provide local blood flow regulation)

29
Q

Bruch’s membrane: what layer of the choroid is it?

A

The innermost layer of the choroid fuses with the retina

Allow nutrients inflow to the retina and remove waste products

30
Q

what are the five layers of Bruch’s membrane?

A
  1. BM of RPE
  2. Inner collagenous zone
  3. Elastic layer
  4. Outer collagenous zone
  5. BM of Choriocapillaris
31
Q

T/F: Bruch’s membrane acellular

A

T

32
Q

what does Bruch’s membrane contain elements of

A

elements of the choroid and RPE

33
Q

what does Bruch’s membrane surround?

A

it surrounds the optic disc and extends peripherally to the ora serrata

34
Q

where is Bruch’s membrane the thickest and the thinnest

A
  • Thickest near the optic disc (2-4 microns)

* Thinner peripherally (1-2 microns)

35
Q

what is the posterior choroid supplied by?

A

10- 20 SHORT POSTERIOR CILIARY ARTERIES (SPCA)

36
Q

what is the anterior choroid supplied by?

A

2 LONG POSTERIOR CILIARY ARTERIES (LPCA) and Anterior Ciliary arteries (ACA)

37
Q

where does the anterior and posterior systems meet?

A

The two systems meet at the equator and are connected with each other via recurrent vessels

38
Q

Drusen:

A

deposit of waste material from the retina

characteristics of AMD

39
Q

where is Drusen found?

A

Between the inner collagenous layer of Bruch’s and BM of RPE

40
Q

Angoid streaks:

A

damage to the elastic layer of bruch’s

**Psuedoxanthoma elasticum, ehlersdanlos syndrome, pagets disease, sickle cell disease, and Idiopathic (PEPSI)

41
Q

Choroidal neovascular membranes (CNVM) results from what?

A

a break in bruch’s membrane

42
Q

what casues Choroidal neovascular membranes (CNVM)?

A

Due to pathological myopia, Exudative ARMD, Histoplasmosis, Choroidal rupture