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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]
He observed "lacunae" (empty spaces) in the deep brain structures after occlusion of 200–800 μm penetrating arteries and connected them with five classic syndromes. These syndromes are still noted today, though lacunar infarcts are diagnosed based on clinical judgment and radiologic imaging.
The accessory visual structures (or adnexa of eye, ocular adnexa, etc.) are the protecting and supporting structures of the eye, including the eyebrow, eyelids, and lacrimal apparatus. The eyebrows, eyelids, eyelashes , lacrimal gland and drainage apparatus all play a crucial role with regards to globe protection, lubrication, and minimizing ...
If the lacunae are located in the macula, they affect acuity. Other types of eye abnormalities are also common, such as one eye being smaller than normal (microphthalmia), changes in the optic nerve, and incomplete closure/slitting of the membranes of the eye . Rapid, involuntary eye movements are common. Since people with Aicardi syndrome have ...
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 ...
They can be grouped into bundles, can form complete tubes located at the periphery, or can occur as single cells or small groups of cells within parenchyma tissues. An isolated sclereid cell is known as an idioblast .
Small variations in the production or outflow of aqueous humor will have a large influence on the intraocular pressure. The drainage route for aqueous humor flow is first through the posterior chamber , then the narrow space between the anterior iris and the posterior lens (contributes to small resistance), through the pupil to enter the ...
Most vessels of the microcirculation are lined by flattened cells of the endothelium and many of them are surrounded by contractile cells called pericytes.The endothelium provides a smooth surface for the flow of blood and regulates the movement of water and dissolved materials in the interstitial plasma between the blood and the tissues.