Blood supply to the eye and adnexa Flashcards
GIve 6 reasons there is a blood supply to the eye
-provides oxygen, nutrients and water
-removes carbon dioxide and metabolic wastes
-hormones
-to mediate the immune system response
-to maintain a constant pH and temperature
-source of pressure
What is the common carotid and what does it consist of?
the main artery that supplies blood to the head and neck
theres a left and a right carotid artery and each divides into the internal carotid and the external carotid
what is the infraorbital artery?
a branch of the external carotid that provides blood supply to the eye
what is the circle of Willis? What arteries does it contain?
the cerebral arterial circle that provides alternative passages for blood flow in case another gets blocked. It contains
-the internal carotid arery
-the middle cerebral artery
-the basilar artery
-vetebral artery
what is the ophthalmic artery?
a branch of the internal carotid that provides blood supply to the adnexa
what are the main branches of the ophthalmic artery?
-posterior ciliary arteries ( short and long)
-lacrimal artery
-central retinal artery
muscular arteries that branch to form:
-anterior ciliary arteries
-supraorbital artery
-medial palpebral arteries
for the central retinal artery,
what structures does it go through and what is it accompanied by?
-goes through the optic nerve behind the eye and the central optic disk
-accompanied by the central retinal vein
how does the central retinal artery supply blood to the optic nerve?
via collateral branches
what forms the blood-retina barrier?
endothelial cells of retinal capillaries and retinal pigment epithelial cells capillaries via tight junctions by zonula occludens
what is autoregulation in the retina?
the maintenance of constant blood flow despite the changes in intraocular pressure and systemic blood pressure controlled by metabolism
how does the Bruch’s membrane change with age?
- it thickens
- it causes decreased permeability
how is dry AMD diagnosed?
staining of the large drusen in the retina as a result of the bruch’s membrane allowing for extracellular debris
what supplies the choroid with blood?
posterior ciliary arteries
what supplies the iris and ciliary body with blood?
anterior ciliary arteries as they anastomose with the branches of the long posterior ciliary arteries
what do the short posterior ciliary arteries supply?
posterior choroid, optic nerve, pia matter of the optic nerve and in some cases the inner retina