Choriod

Question 1

What structures are involved in the uveal tract?

Answer 1

the choroid, iris, and ciliary body

Question 2

what tunic is the uveal tract considered

Answer 2

the vascular layer or tunic

Question 3

what is considered the anterior uvea

Answer 3

the ciliary body and iris

Question 4

what is considered the posterior uvea

Answer 4

the choriod

Question 5

what 3 places is the uvea attached to the sclera

Answer 5

scleral spur, vortex veins, and the optic nerve

Question 6

how is the uvea lined

Answer 6

by two continuous layers derived from the neuroectoderm

Question 7

what is the uvea mainly composed of

Answer 7

melanocytes, blood vessels and connective tissue

Question 8

what is the primary function of the choroid

Answer 8

to nourish the outer layers of the retina - also heat exchange from the retina due to the high volume of blood

Question 9

how much blood does the choroid account for flowing through the eye

Answer 9

85%

Question 10

what 3 layers is the choroid divided into

Answer 10

Bruch’s membrane, capillary layer, and vessel layer

Question 11

how many layers is Bruch’s membrane

Answer 11

5 layers: basement membrane (choriocapillaries), outer collagen, elastic fibers, inner collagen, basement membrane (RPE)

Question 12

What is the function of Bruch’s membrane

Answer 12

passage of fluid from the choriocapillaries to the retina

Question 13

where does drusen appear

Answer 13

between the basement membrane of the RPE and inner collagen layer

Question 14

Does Bruch’s membrane have innervation

Answer 14

No

Question 15

which choriod layer will thicken throughout life

Answer 15

Bruch’s membrane- in the macula

Question 16

what is the choriocapillary layer

Answer 16

a single layer composed of wide-bore capillaries with sac-like dilations

Question 17

are the anterior capillaries of the choriocapillaries fenestrated?

Answer 17

yes, for production of aqueous humor

Question 18

are the posterior capillaries of the choriocapillaries fenestrated

Answer 18

no, (near the ciliary muscle)

Question 19

where are the choriocapillaries the sole provider of nutrients to

Answer 19

the macula

Question 20

what type of network is near the macula

Answer 20

a lobulated network

Question 21

are the anastomoses between the lobules of the choriocapillaries

Answer 21

no, if one lobule is damages or destroyed the other lobules will remain working

Question 22

what layer of the choroid is the most external

Answer 22

the vessel layer

Question 23

what is Sattler’s layer

Answer 23

the inner layer of medium sized vessels

Question 24

what is Haller’s layer

Answer 24

the outer layer of large vessels

Question 25

what arteries feed the vessel layer

Answer 25

branches from the short posterior ciliary arteries (10-20)

Question 26

what is the choroidal stroma

Answer 26

a sparse region mostly occupied by blood vessels

Question 27

what is the suprachoroid lamina

Answer 27

thin pigmented sheets of connective tissue that travel across the suprachoroidal space

Question 28

what is the suprachoroial space

Answer 28

a potential space between the choriod and sclera where long and short posterior ciliary arteries and nerves travel

Question 29

what is unique about the arterial and venus system of the choroid

Answer 29

they do not parallel each other

Question 30

what veins drain the choriod

Answer 30

the vortex veins

Question 31

what innervates the choroid

Answer 31

long and short posterior ciliary nerves

Question 32

what signal do the long posterior ciliary nerves carry

Answer 32

sensory fibers from the cornea, iris, ciliary muscle

Question 33

what type of nerves come from the superior cervical ganglion

Answer 33

Long posterior ciliary postganglionic sympathetic fibers - go to the dilator muscle of the iris

Question 34

where do the long posterior ciliary nerves enter and travel in the eye

Answer 34

pierce the sclera about 3-4mm from the optic nerve and travel in the suprachoroidal space

Question 35

where do the long ciliary nerves arise from

Answer 35

the nasociliary branch of the ophthalmic division of the trigeminal nerve (CN 5)

Question 36

why is the blood flow so high in the choroid

Answer 36

there is low resistance of the choroidal capillaries, they are wider and broader than retinal capillaries

Question 37

what is the oxygen content for the veins in the choroid

Answer 37

about 95% to that of the arteries

Question 38

why might the choroid have such a low oxygen content

Answer 38

it suggests that it may play a role in heat exchange from the retina

Question 39

Is the choroidal vasculature autoregulated or neuroregulated

Answer 39

neuroregulated