Ocular blood supply, aqeuous formation flow and drainage.

What is the anterior chamber angle ?

• area where the iris and cornea meet infront of eye.

• Contains structures like trabecular meshwork which are crucial for draining fluid from eye.

• A wider angle allows for free drainage - narrower angle causes fluid flow to be restricted which can cause and increase in pressure - glaucoma

Briefly describe blood flow through heart :

• Vena cava

• Right atrium

• Tricuspid valve

• Right ventricle

• Semi- lunar valves

• Pulmonary artery

• Pulmonary vein left atrium

• Bicuspid valve

• Left ventricle

• Semi- lunar valve

• Aorta

• Body

Why does the eye require blood supply ?

• to transport oxygen

• Ensures thermoregulation

What is the internal carotid artery?

• a major blood vessel that supplies oxygenated blood to eye, nose, forehead.

• Major branches include the ophthalmic artery

The ophthalmic artery then branches into ……

• central retina artery

• Lacrimal artery

• Muscular arteries

• Ciliary artery

• Supraorbital artery

• Medial palpebral arteries

• Dorsal nasal artery

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Describe central retinal artery:

• Supplies blood to the inner layers of the retina

• Enters the optic disc

Describe the lacrimal artery:

• supplies lacrimal gland

Describe muscular arteries:

• supply eom

• Branches off to anterior ciliary artery ( important for iris an ciliary body)

Describe the ciliary arteries:

• supply choroid and optic nerve

Short posterior artery:

• supply choroid and optic disc

Long posterior artery:

• supply ciliary body and iris

Describe supraorbital arteries:

• supplies the forehead and scalp

Describe the palpebral arteries:

• supple eyelid and conjunctiva

Describe dorsal nasal artery:

• supplies bridge of nose

What is the importance of the veins in the orbit?

• drain blood from eyeball, eom, lacrimal glands

• Regulates pressure

* there are no valves in veins so infection from face, nose and sinus can spread to orbit,

Name the 4 main veins and their function:

Superior ophthalmic vein:

• main drainage of orbit

Central retinal vein:

• drains blood from retina

Vortex vein:

• drains the choroid

Anterior ciliary veins:

• drains blood from ciliary body, iris and sclera

What is aqeous humour ?

• clear and colourless liquid

• Supplies metabolic needs of lens and cornea

• Contains glucose, amino acids

• Supports wall of eyeball as it helps eye maintain pressure and optical shape.

How is aqueous humour produced, circulated and drained ?

• The aqueous humour is produced by the ciliary body by a I’ve secretion. They contain capillaries which actively secrete aqeous humour.

• Once produced, its then released into the posterior chamber ( space between iris and lens)

• Flows through pupil into the anterior chamber (space between cornea and iris) - this is the circulation

• drained at anterior chamber angle-

• Through trabecular meshwork, into canal of schlemm then into the episcleral veins

• Narrow anterior chamber angle= prevents aqueous drainage

Ciliary processes → posterior chamber → pupil → anterior chamber→ anterior chamber angle→ trabecular meshwork → canal of Schelmm → collector vessels → aqueous veins→ episcleral veins

IOP is maintained by…..

• rate of formation

• Rate of drainage through the trabecular meshwork