Arteriovenous nicking, also known as AV nicking, is the phenomenon where, on examination of the eye, a small artery (arteriole) is seen crossing a small vein (venule), which results in the compression of the vein with bulging on either side of the crossing. This is most commonly seen in eye disease caused by high blood pressure (hypertensive retinopathy). It is thought that, since the arteriole and venule share a common sheath, the arteriole's thicker walls push against those of the venule forcing the venule to collapse. This makes the venule form an hourglass shape around the arteriole.
|
|
Blood exits the glomerular capillaries by an efferent arteriole instead of a venule, as is seen in the majority of capillary systems (Fig. 4). This provides tighter control over the blood flow through the glomerulus, since arterioles dilate and constrict more readily than venules, owing to their thick circular smooth muscle layer (tunica media). The blood exiting the efferent arteriole enters a renal venule, which in turn enters a renal interlobular vein and then into the renal vein. Cortical nephrons near the corticomedullary junction (15% of all nephrons) are called juxtamedullary nephrons.
|
|
Portal hypertensive gastropathy can also be treated with endoscopic treatment delivered through a fibre-optic camera into the stomach. Argon plasma coagulation and electrocautery have both been used to stop bleeding from ectatic vessels, and to attempt to obliterate the vessels, but have limited utility if the disease is diffuse. Transjugular intrahepatic portosystemic shunt procedures, or TIPS involve decompressing the portal vein by shunting a portal venule to a lower pressure systemic venule, under guidance with fluoroscopy. Since it treats the root cause of portal hypertension gastropathy, it has been putatively used for the condition.
|
|
A venule is a very small blood vessel in the microcirculation that allows blood to return from the capillary beds to drain into the larger blood vessels, the veins. Venules range from 7μm to 1mm in diameter. Veins contain approximately 70% of total blood volume, 25% of which is contained in the venules. Many venules unite to form a vein.
|
|
Epiploic appendages are also called appendices epiploicae. The appendages themselves are 50–100 appendages that are oriented in two rows anterior and posterior. The appendages are parallel to the superficial section of the taenia coli. Furthermore, the appendages are between 0.5 and 5 cm long, each appendage is attached with one or two arterioles and a venule within vascular stalks attached to the colon.
|
|
SPARC-like protein 1 (SPARCL1 or SC1), also known as hevin (short for high endothelial venule protein), is a secreted protein with high structural similarity to SPARC. It interacts with the extracellular matrix to create intermediate states of cell adhesion. Due to its dynamic extracellular roles, being implicated in cancer metastasis and inflammation, it is considered a matricellular protein. In humans hevin is encoded by the SPARCL1 gene.
|
|
Salus's sign is a clinical sign in which deflection of retinal venules can be seen on fundoscopy occurring in patients with hypertensive retinopathy.Hypertension at Medscape Arteriosclerosis causes shortening or lengthening of arterioles, which causes venules to be moved at points where arterioles and venules cross over. This is seen at right-angle crossing points, where the venule crosses the arteriole in a horseshoe shape.Sebastian Wolf, Berndt Kirchof, Martin Reim.
|
|
A female generally lays 500-1,000 eggs in a day. The female only leaves the male briefly for laying eggs. It has to because only it can enter the small and narrow peripheral venule in the submucosa so that the eggs can be released into the bladder. The embryonated eggs penetrate the bladder mucosa using proteolytic enzymes, aided by their terminal spines and by the contraction of the bladder.
|
|
Glomus tumors were first described by Hoyer in 1877 while the first complete clinical description was given by Masson in 1924. Histologically, glomus tumors are made up of an afferent arteriole, anastomotic vessel, and collecting venule. Glomus tumors are modified smooth muscle cells that control the thermoregulatory function of dermal glomus bodies. As stated above, these lesions should not be confused with paragangliomas, which were formerly also called glomus tumors in now-antiquated clinical usage.
|
|
Venule walls have three layers: An inner endothelium composed of squamous endothelial cells that act as a membrane, a middle layer of muscle and elastic tissue and an outer layer of fibrous connective tissue. The middle layer is poorly developed so that venules have thinner walls than arterioles. They are porous so that fluid and blood cells can move easily from the bloodstream through their walls. Short portal venules between the neural and anterior pituitary lobes provide an avenue for rapid hormonal exchange via the blood.
|
|
The epidermis primarily consists of keratinocytes (proliferating basal and differentiated suprabasal), which comprise 90% of its cells, but also contains melanocytes, Langerhans cells, Merkel cells, and inflammatory cells. Epidermal thickenings called Rete ridges (or rete pegs) extend downward between dermal papillae.TheFreeDictionary > rete ridge Citing: The American Heritage Medical Dictionary Copyright 2007, 2004 Blood capillaries are found beneath the epidermis, and are linked to an arteriole and a venule. The epidermis itself has no blood supply and is nourished almost exclusively by diffused oxygen from the surrounding air.
|
|
Specifically within and between the pituitary lobes is anatomical evidence for confluent interlobe venules providing blood from the anterior to the neural lobe that would facilitate moment-to-moment sharing of information between lobes of the pituitary gland. In contrast to regular venules, high endothelial venules are a special type of venule where the endothelium is made up of simple cuboidal cells. Lymphocytes exit the blood stream and enter the lymph nodes via these specialized venules when an infection is detected. Compared with arterioles, the venules are larger with much weaker muscular coat.
|
|
Illustration depicting extracellular matrix in relation to epithelium, endothelium and connective tissue. The formation of capillaries from pre-existing blood vessels requires the remodeling of both the peicapillary membrane of the parent venule, as well as the local and distal ECM. At the onset of angiogenesis endothelial cells (EC) must remodel three different barriers in order to migrate and invade the target tissue. First is the basement membrane between the endothelium and vascular smooth muscle cells or pericytes, followed by the fibrin gel formed from fibrinogen that is leaked from the vasculature, and finally the extracellular matrix in the target tissue.
|
|
In the “Trooper Fault” review, Sloman said that at that time he had tracked down some 14 titles of Lamburn's on natural history subjects, under various names, in particular Lamburn, Lambourne, Crompton. Fewer than fourteen could be located in writing this article. In writing on scientific matters Lamburn certainly wrote mainly under the name “John Crompton”. As John Crompton he made no claim to scientific expertise, but wrote explicitly as a “layman writing for laymen”.Anonymous, “Science: The Clever Arachnids”, “Time” magazine, Monday, Jul. 03, 1950 Accordingly, the books include occasional slip-ups such as “coastal” (instead of “costal”) venule, though of course some of those might well be attributed to printers’ devils.
|
|
Beginning in 1937 Batson began a series of injection experiments investigating the anatomy and physiology of the cerebrospinal venous system. His carefully documented results demonstrated the continuity of the venous systems of the brain and the spine, as injections of contrast dyes into venous systems feeding into the spinal venous plexus led to the appearance of contrast material in the cerebral veins (Figures 5 and 7, Batson 1940). Batson noted "the extensive filling of the vertebral veins, the superior longitudinal sinus, transverse sinus as well as other dural and cerebral veins" following injection of radiopaque material into a superficial venule in the left breast (Batson 1940, Figure 5, page 143). Subsequent studies by multiple independent authors replicated Batson's findings of the continuity of the cerebral and vertebral venous systems, and the important physiological consequences of this continuity.
|
|