Blood Supply To Eye

Question 1

Functions of blood to the eye

Answer 1

Provides oxygen, nutrients and water
Source of pressure
Homeostasis

Question 2

What structures are supported by the two types of carotid arteries

Answer 2

Internal carotid- structures internal to skull
External carotid- structures external to skull inc the ocular adnexa

Question 3

What is the function of the circle of willis

Answer 3

Maintains adequate perfusion pressure within the brain
Ensures continuous blood supply to the brain even if there is a blockage or compromise in one of the arteries

Question 4

Which branch of the ophthalmic artery pierces and travels in the optic nerve

Answer 4

Central retinal artery

Question 5

What is the function of collateral branches of central retinal artery

Answer 5

Provides blood supply to optic nerve and pia matter

Question 6

Describe the branching of the central retinal artery in the eye

Answer 6

Divides into superior and inferior branches
Which divide into temporal and nasal branches

Question 7

Which retinal layer do arteries and veins travel within

Answer 7

Nerve fibre layer

Question 8

What does auto regulation in the retina mean

Answer 8

the ability of retinal blood vessels to maintain a constant blood flow and perfusion despite changes in IOP and systemic blood pressure

Question 9

What are some common age-related chsnges to retinal circulation

Answer 9

Cell loss
Narrowing of vascular lumen (arteriosclerosis)
Diminished perfusion
Thickening of Bruch’s membrane
Thickening of pericyte basement membrane

Question 10

Which structures provides blood supply to 1. Inner retina 2. Choroid

Answer 10

1. Central retinal artey
2. Posterior ciliary arteries

Question 11

What is the function and “occurence rate” of the cilioretinal artery

Answer 11

Provides additional source of blood flow to the macula
Present in 15-50% of the population

Question 12

How does the cilioretinal artery differ from the main retinal blood supply

Answer 12

Origin
Main blood supply originates from central retinal artery
Cilioretinal artery branches from one of the posterior ciliary arteries

Question 13

Describe the dual retinal blood supply

Answer 13

Central Retinal artery- inner retina
Posterior Ciliary Arteries- outer retina

Question 14

Describe the differences between short and long posterior ciliary arteries

Answer 14

Short- pierce eyeball
Supplies choroid, optic nerve, pia
Long- pierce sclera
Supplies ciliary body, anterior choroid

Question 15

Describe the origin of anterior ciliary arteries

Answer 15

Branch from arteries supplying recti muscles
Exit the recti near the insertion points of the recti to eyeball

Question 16

What structures get their blood supply from medial palpebral arteries

Answer 16

Eyelids, anastomose

Question 17

What causes a low blood pressure in veins in the eye compared to the rest of the body

Answer 17

Absence of valves

Question 18

Which cells rovide the blood-retina barrier

Question 19

Which arteries provide a blood supply to photoreceptors

Question 20

What is the significance of a dual blood supply

Answer 20

• photoreceptors are metabolically very active in the dark, so they use a lot of O2 from the choroid. No oxygen is available to diffuse to inner retina
• outer retina has a high O2 requirement, while the inner retina blood supply is just sufficient for the cells in the toplayer

Question 21

Which 3 types of cells receive a blood supply from the central retinal artery

Answer 21

1. Retinal ganglion cells
2. Intermediary neurons
3. Mueller cells

Answer 22

Which arteries orovide a blood supply to the iris