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The central part of the retina where the light rays are focused after passing through the pupil and the lens is a circular area called the macula. The center of this circular area is the fovea. The fovea and a small area surrounding it are not supplied by the central retinal artery or its branches, but instead by the choroid.
The ophthalmic artery (OA) is an artery of the head.It is the first branch of the internal carotid artery distal to the cavernous sinus.Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some structures in the nose, face, and meninges.
Intrinsic ocular muscles [1] or intraocular muscles [2] are muscles of the inside of the eye structure. The intraocular muscles are responsible for the protraction and retraction of the eyelids and reaction to light and pupil accommodation. [2] They're different to the extraocular muscles that are outside of the eye and control the external ...
The front visible part of the eye is made up of the whitish sclera, a coloured iris, and the pupil. A thin layer called the conjunctiva sits on top of this. The front part is also called the anterior segment of the eye. The eye is not shaped like a perfect sphere; rather it is a fused two-piece unit, composed of an anterior (front) segment and ...
The afferent arterioles are a group of blood vessels that supply the nephrons in many excretory systems. They play an important role in the regulation of blood pressure as a part of the tubuloglomerular feedback mechanism. The afferent arterioles branch from the renal artery, which supplies blood to the kidneys.
The extraocular muscles, or extrinsic ocular muscles, are the seven extrinsic muscles of the eye in humans and other animals. [1] Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye. The other muscle, the levator palpebrae superioris, controls eyelid elevation.
An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. [1] Arterioles have muscular walls (usually only one to two layers of smooth muscle cells) and are the primary site of vascular resistance. The greatest change in blood pressure and velocity of blood flow ...
The iris sphincter muscle (pupillary sphincter, pupillary constrictor, circular muscle of iris, circular fibers) is a muscle in the part of the eye called the iris.It encircles the pupil of the iris, appropriate to its function as a constrictor of the pupil.