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Aerenchyma in stem cross section of a typical wetland plant. Aerenchyma or aeriferous parenchyma [1] or lacunae, is a modification of the parenchyma to form a spongy tissue that creates spaces or air channels in the leaves, stems and roots of some plants, which allows exchange of gases between the shoot and the root. [2]
The uvea (/ ˈ j uː v i ə /; [1] derived from Latin: uva meaning "grape"), also called the uveal layer, uveal coat, uveal tract, vascular tunic or vascular layer, is the pigmented middle layer of the three concentric layers that make up an eye, precisely between the inner retina and the outer fibrous layer composed of the sclera and cornea.
Location of infarct Presentation Pure motor stroke/hemiparesis (most common lacunar syndrome: 33–50%) posterior limb of the internal capsule, basilar part of pons, corona radiata It is marked by hemiparesis or hemiplegia that typically affects the face, arm, or leg of the side of the body opposite the location of the infarct.
Schlemm's canal, also known as the canal of Schlemm, and as the scleral venous sinus, is a circular lymphatic-like vessel in the eye. It collects aqueous humor from the anterior chamber and delivers it into the episcleral blood vessels. Canaloplasty may be used to widen it.
The fovea centralis is a small, central pit composed of closely packed cones in the eye.It is located in the center of the macula lutea of the retina. [1] [2]The fovea is responsible for sharp central vision (also called foveal vision), which is necessary in humans for activities for which visual detail is of primary importance, such as reading and driving.
Basically, the Retinal Vessel Analyzer measures the diameters of small arteries and vein in the posterior segment of the eye. In static retinal vessel analysis this is a snapshot, in dynamic vessel analysis (DVA) a 12.5 Hz optoelectric flickering light induces a stimulation of a specific segment of the retina to which the vessels react by a ...
The eyes are always affected, and most people have impaired vision. During an eye examination, areas with less pigment (retinal lacunae) appear as white spots in the fundus, which is due to the absence of retinal pigment cells and other structures in these areas. If the lacunae are located in the macula, they affect acuity.
Thus if the central retinal artery gets occluded, there is complete loss of vision in that eye even though the fovea is not affected. The entire retina (with the exception of the fovea) becomes pale and swollen and opaque while the central fovea still appears reddish (this is because the choroid color shows through).