query: where does blood flow from the renal veins

pos: Renal vein and nutcracker syndrome (renal vein entrapment syndrome). Renal vein The renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava. They carry the blood filtered by the kidney. There is one vein per kidney, that divides into 4 divisions upon entering the kidney: Because the inferior vena cava is on the right half of the body, the left renal vein is generally the longer of the two. Because the inferior vena cava is not laterally symmetrical, the left renal vein often receives the following veins: This is in contrast to the right side

pos: Renal vein Renal vein The renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava. They carry the blood filtered by the kidney. There is one vein per kidney, that divides into 4 divisions upon entering the kidney: Because the inferior vena cava is on the right half of the body, the left renal vein is generally the longer of the two. Because the inferior vena cava is not laterally symmetrical, the left renal vein often receives the following veins: This is in contrast to the right side of the body, where these veins drain

pos: Renal vein and nutcracker syndrome (renal vein entrapment syndrome). Renal vein The renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava. They carry the blood filtered by the kidney. There is one vein per kidney, that divides into 4 divisions upon entering the kidney: Because the inferior vena cava is on the right half of the body, the left renal vein is generally the longer of the two. Because the inferior vena cava is not laterally symmetrical, the left renal vein often receives the following veins: This is in contrast to the right side

pos: Inferior vena cava Inferior vena cava The inferior vena cava (or IVC) is a large vein that carries deoxygenated blood from the lower and middle body into the right atrium of the heart. Its walls are rigid and has valves so the blood does not flow down via gravity. It is formed by the joining of the right and the left common iliac veins, usually at the level of the fifth lumbar vertebra. The inferior vena cava is the lower ("inferior") of the two venae cavae, the two large veins that carry deoxygenated blood from the body to the right atrium of the

pos: Giraffe have unusually high heart rates for their size, at 150 beats per minute. When the animal lowers its head the blood rushes down fairly unopposed and a rete mirabile in the upper neck, with its large cross sectional area, prevents excess blood flow to the brain. When it raises again, the blood vessels constrict and direct blood into the brain so the animal does not faint. The jugular veins contain several (most commonly seven) valves to prevent blood flowing back into the head from the inferior vena cava and right atrium while the head is lowered. Conversely, the blood vessels

neg: Common raven physiology system, which involves the afferent veins, obtains blood from the ischiadic and external iliac veins. The renal portal valve is situated between the renal portal vein and the common iliac vein which leads to the posterior vena cava. Closing of the valve directs the blood to flow into the renal portal vein, and when the valve is open, blood flows into the vena cava. After entering the renal portal vein, blood enters the peritubular blood supply. Here, blood from the portal veins and the efferent arterioles are mixed and travel out of the kidneys through the efferent veins. Alternatively, blood

neg: Renal vein thrombosis will enlarge, reaching its maximum size within a week. An ultrasound imaging can be used to observe and track the size of the kidneys in RVT patients. Ultrasound is not efficient for use in detecting blood flow in the renal veins and artery. Instead a color doppler ultrasound may be used to detect renal blood flow. It is most commonly used to detect RVT in patients who have undergone renal transplantation. CT angiography is currently the top choice in diagnosing RVT. It is non-invasive, relatively cheap and fast with high accuracy. CT scanning can be used to detect renal enlargement,

neg: Renal portal system all the blood from the tail (if present), groin, pelvic area, and hind legs is forced to pass directly into the posterior vena cava, and the only blood passing out of the kidney through the renal vein is that that entered it through the renal artery. The subcardinals become the part of the posterior vena cava between the hepatic vein and the renal veins, and other portions become the internal gonadal (spermatic or ovarian) veins, and the suprarenal veins. The posterior cardinal veins become the veins of the pelvis, tail, and hind legs, and the part of the azygos vein

neg: Renal portal system Renal portal system A renal portal system is a portal venous system found in all living vertebrates except for hagfish, lampreys, and mammals. Its function is to move blood from the renal glomeruli to the peritubular plexus that surround the proximal and distal convoluted tubules. The main channel is the renal portal vein, developed from the posterior cardinal vein, which brings venous blood from the tail and groin to the kidney, where it is shunted into a capillary network around the convoluted tubules. The blood then enters the renal vein, passing either through the subcardinal veins and into the posterior

neg: Renal vein thrombosis problems (damage to the renal vein), clotting disorders, diabetes, consumption of ciclosporin or an unknown problem. Patients who have undergone a kidney transplant are commonly prescribed ciclosporin, an immunosuppressant drug which is known to reduce renal blood flow, increase platelet aggregation in the blood and cause damage to the endothelial tissue of the veins. In a clinical study conducted by the Nuffield Department of Surgery at the Oxford Transplant Centre, UK, transplant patients were given low doses of aspirin, which has a some anti-platelet activity. There is risk of bleeding in transplant patients when using anticoagulants like warfarin and herapin.

neg: Atrium (heart) interrupt blood flow during atrial systole. (2) The atrial systole contractions are incomplete and thus do not contract to the extent that would block flow from the veins through the atria into the ventricles. During atrial systole, blood not only empties from the atria to the ventricles, but blood continues to flow uninterrupted from the veins right through the atria into the ventricles. (3) The atrial contractions must be gentle enough so that the force of contraction does not exert significant back pressure that would impede venous flow. (4) The "let go" of the atria must be timed so that

neg: Ultrasonography of chronic venous insufficiency of the legs with a retrograde flow. When there is a GSV thrombosis or other cause of insufficiency, the Giacomini vein can divert the blood flow to the SSV and from there to the popliteal vein. Where surgery, other than stripping or laser ablation is intended, the examiner will make reference to the blood flow direction in this vein, as it will be of importance. Perforator veins play a very special role in the venous system, carrying blood from superficial to deep veins. During the muscular systole their valves close and stop any blood flow coming from the deep to the superficial veins.

neg: PAH clearance PAH clearance Para-aminohippurate (PAH) clearance is a method used in renal physiology to measure renal plasma flow, which is a measure of renal function. PAH is completely removed from blood that passes through the kidneys (PAH undergoes both glomerular filtration and tubular secretion), and therefore the rate at which the kidneys can clear PAH from the blood reflects total renal plasma flow. The concentration of PAH is measured in one arterial blood sample (P) and one urine sample(U). The urine flow (V) is also measured. Renal perfusion flow is then calculated by: What is calculated is the effective renal plasma

neg: Foramen secundum blood. The foramen secundum and foramen ovale act as a shunt where blood bypasses the lungs and does not become oxygenated. To provide proper blood flow as a newborn, the foramen secundum and foramen ovale must close at birth. Since the lungs now require a significant amount of blood flow, the vessels going to and from the lungs undergo dilation. While the pulmonary artery and pulmonary veins are dilating, the umbilical artery and umbilical vein are severed at the cutting of the umbilical cord, or the funiculus umbilicalis. This combination results in a reversal of pressure differences between the atria,

neg: Renal medulla oxygen tension and more importantly, a critical sensitivity to hypotension, hypoxia, and blood flow. The renal medulla extracts oxygen at a ratio of ~80% making it exquisitely sensitive to small changes in renal blood flow. The mechanisms of many perioperative renal insults are based on the disruption of adequate blood flow (and therefore oxygen delivery) to the renal medulla. Renal medulla The renal medulla is the innermost part of the kidney. The renal medulla is split up into a number of sections, known as the renal pyramids. Blood enters into the kidney via the renal artery, which then splits up

neg: Ultrasonography of chronic venous insufficiency of the legs become the reference standard used in the assessment of the condition and hemodynamics of the veins of the lower limbs. The normal physiological blood flow is anterograde, flowing from the periphery towards the heart, so that the evidence of an opposite, retrograde flow might indicate a pathology. The presence of a reflux is likewise of note; a reflux when not isolated in a vein (as simply retrograde), means that the blood flow is bi-directional where once the flow had been only anterograde. No contraindications are known for this examination. Ultrasonography does not involve the use of ionizing radiation, and the

neg: Renal blood flow Renal blood flow In the physiology of the kidney, renal blood flow (RBF) is the volume of blood delivered to the kidneys per unit time. In humans, the kidneys together receive roughly 25% of cardiac output, amounting to 1.1 L/min in a 70-kg adult male. RBF is closely related to renal plasma flow (RPF), which is the volume of blood plasma delivered to the kidneys per unit time. While the terms generally apply to arterial blood delivered to the kidneys, both RBF and RPF can be used to quantify the volume of venous blood exiting the kidneys per unit time.

neg: Renal blood flow entering the kidney via the renal artery has two points of exit, the renal vein and the ureter. The mass entering through the artery per unit time must equal the mass exiting through the vein and ureter per unit time: where "P" is the arterial plasma concentration of the substance, "P" is its venous plasma concentration, "U" is its urine concentration, and "V" is the urine flow rate. The product of flow and concentration gives mass per unit time. As mentioned previously, the difference between arterial and venous blood flow is negligible, so "RPF" is assumed to be equal to

neg: Analgesic nephropathy synthesis depends upon the cyclooxygenases. Aspirin and other NSAIDs are inhibitors of the cyclooxygenases. In the kidney, this inhibition results in decreased PGE concentration causing a reduction in blood flow. Because blood flow to the kidney first reaches the renal cortex (outside) and then the renal medulla (inside), the deeper structures of the kidney are most sensitive to decreased blood flow. Thus the innermost structures of the kidney, known as the renal papillae, are especially dependent on prostaglandin synthesis to maintain adequate blood flow. Inhibition of cyclooxygenases therefore rather selectively damages the renal papillae, increasing the risk of renal papillary

neg: Clearance (pharmacology) does not completely remove a substance from the total renal plasma flow." From a mass transfer perspective and physiologically, volumetric blood flow (to the dialysis machine and/or kidney) is only one of several factors that determine blood concentration and removal of a substance from the body. Other factors include the mass transfer coefficient, dialysate flow and dialysate recirculation flow for hemodialysis, and the glomerular filtration rate and the tubular reabsorption rate, for the kidney. A physiologic interpretation of clearance (at steady-state) is that clearance is "a ratio of the mass generation and blood (or plasma) concentration". Its definition follows from

neg: Renal blood flow (RBF) can be calculated from a patient's RPF and hematocrit using the following equation: If the kidney is methodologically perfused at moderate pressures (90–220 mm Hg performed on an experimental animal; in this case, a dog), then, there is a proportionate increase of: Along with the increase in pressure. At low perfusion pressures, Angiotensin II may act by constricting the efferent arterioles, thus mainlining the GFR and playing a role in autoregulation of Renal Blood Flow. Patients with poor renal perfusion caused by drugs that inhibit angiotensin-converting enzyme face Renal failure. Renal blood flow In the physiology of the kidney,

neg: Renal blood flow In this context, the terms are commonly given subscripts to refer to arterial or venous blood or plasma flow, as in RBF, RBF, RPF, and RPF. Physiologically, however, the differences in these values are negligible so that arterial flow and venous flow are often assumed equal. Renal plasma flow is the volume of plasma that reaches the kidneys per unit time. Renal plasma flow is given by the Fick principle: This is essentially a conservation of mass equation which balances the renal inputs (the renal artery) and the renal outputs (the renal vein and ureter). Put simply, a non-metabolizable solute

neg: Renal portal system cardinal veins or through the posterior vena cava. In lungfish and tetrapods, the renal portal vein is joined by a vein traveling upwards from the abdominal vein, which can bring venous blood from the hind limbs and ventral body wall into the renal portal system, or alternatively, enable blood from the tail and groin to pass into the hepatic portal system, already served by blood from the gut, via the hepatic portal vein, and from the hind legs and ventral body wall, via the abdominal vein. In fishes and salamanders, the renal portal vein branches and enters a capillary network

neg: Varicose veins Varicose veins Varicose veins are veins that have become enlarged and twisted. The term commonly refers to the veins on the leg, although varicose veins can occur elsewhere. Veins have pairs of leaflet valves to prevent blood from flowing backwards (retrograde flow or venous reflux). Leg muscles pump the veins to return blood to the heart, against the effect of gravity. When veins become varicose, the leaflets of the valves no longer meet properly, and the valves do not work. This allows blood to flow backwards and the veins to enlarge even more. Varicose veins are most common in the

neg: Ultrasonography of chronic venous insufficiency of the legs the results is subjective and reliant on an understanding of venous hemodynamics. (A mapping does help the reproducibility and the inter-observer agreement of this examination). The examination is made even more difficult because there can be dilated veins without insufficiency, (by hyper-debit), and non dilated but incompetent veins. Moreover, veins can be discretely incompetent in summer but then be normal in winter. Also, by definition of insufficiency, (insufficient blood flow) blood may be seen to flow freely in both directions, anterograde and retrograde between two valves. Another problem when dealing with the superficial venous system, is that venous anatomy is

neg: Renal artery stenosis Renal artery stenosis Renal artery stenosis is the narrowing of one of the renal arteries, most often caused by atherosclerosis or fibromuscular dysplasia. This narrowing of the renal artery can impede blood flow to the target kidney, resulting in renovascular hypertension – a secondary type of high blood pressure. Possible complications of renal artery stenosis are chronic kidney disease and coronary artery disease. Most cases of renal artery stenosis are asymptomatic, and the main problem is high blood pressure that cannot be controlled with medication. Decreased kidney function may develop if both kidneys do not receive adequate blood flow, furthermore

neg: Varicose veins the Queen's guard, lectern orators, security guards, etc. Varicose veins Varicose veins are veins that have become enlarged and twisted. The term commonly refers to the veins on the leg, although varicose veins can occur elsewhere. Veins have pairs of leaflet valves to prevent blood from flowing backwards (retrograde flow or venous reflux). Leg muscles pump the veins to return blood to the heart, against the effect of gravity. When veins become varicose, the leaflets of the valves no longer meet properly, and the valves do not work. This allows blood to flow backwards and the veins to enlarge even

neg: Renal blood flow from the blood during a single pass through the kidney. (Accordingly, the plasma concentration of PAH in renal venous blood is approximately zero.) Setting "P" to zero in the equation for RPF yields which is the equation for renal clearance. For PAH, this is commonly represented as Since the venous plasma concentration of PAH is not exactly zero (in fact, it is usually 10% of the PAH arterial plasma concentration), eRPF usually underestimates RPF by approximately 10%. This margin of error is generally acceptable considering the ease with which PAH infusion allows eRPF to be measured. Finally, renal blood flow

neg: Ultrasonography of chronic venous insufficiency of the legs and larger femoral and iliac veins. Here the flow is either modulated by the respiratory rhythm or is continuous in cases where the flow is high. The thinner veins do not have a spontaneous flow. However, in some circumstances the blood flow is so slow that it can be seen as some echogenic material moving within the vein, in "spontaneous contrast". This material can easily be mistaken for a thrombus, but can also easily be discounted by testing the vein's compressibility. To evidence the blood flow direction there are some techniques that the examiner can use to accelerate blood flow

neg: Angiotensin renal blood flow depending on the setting. Increases in systemic blood pressure will maintain renal perfusion pressure; however, constriction of the afferent and efferent glomerular arterioles will tend to restrict renal blood flow. The effect on the efferent arteriolar resistance is, however, markedly greater, in part due to its smaller basal diameter; this tends to increase glomerular capillary hydrostatic pressure and maintain glomerular filtration rate. A number of other mechanisms can affect renal blood flow and GFR. High concentrations of Angiotensin II can constrict the glomerular mesangium, reducing the area for glomerular filtration. Angiotensin II is a sensitizer to tubuloglomerular

neg: William Harvey they did not allow blood to flow up, but only down. This led Harvey to believe that the veins allowed blood to flow to the heart, and the valves maintained the one way flow. Contrary to a popular misconception, Harvey did not predict the existence of capillaries. His observations convinced him that direct connection between veins and arteries are unnecessary; he wrote "blood permeates the pores" in the flesh and it is "absorbed and imbibed from every part" by the veins. Harvey's discovery of the circulation of the blood was based on inference, not direct observation, and was incompatible with

neg: Kidney venules that converge into interlobular veins. As with the arteriole distribution, the veins follow the same pattern: the interlobular provide blood to the arcuate veins then back to the interlobar veins, which come to form the renal vein exiting the kidney for transfusion for blood. The table below shows the path that blood takes when it travels through the glomerulus, traveling "down" the arteries and "up" the veins. However, this model is greatly simplified for clarity and symmetry. Some of the other paths and complications are described at the bottom of the table. The interlobar artery and vein (not to

neg: Bird into individual organs and tissues they are further divided to increase surface area and slow blood flow. Blood travels through the arterioles and moves into the capillaries where gas exchange can occur. Capillaries are organized into capillary beds in tissues; it is here that blood exchanges oxygen for carbon dioxide waste. In the capillary beds blood flow is slowed to allow maximum diffusion of oxygen into the tissues. Once the blood has become deoxygenated it travels through venules then veins and back to the heart. Veins, unlike arteries, are thin and rigid as they do not need to withstand extreme

neg: Cardiac output demand pump that does not regulate its own output. When the body has a high metabolic oxygen demand, the metabolically controlled flow through the tissues is increased, leading to a greater flow of blood back to the heart, leading to higher cardiac output. The capacitance, also known as compliance, of the arterio-vascular channels that carry the blood also controls cardiac output. As the body's blood vessels actively expand and contract, the resistance to blood flow increases and decreases respectively. Thin-walled veins have about eighteen times the capacitance of thick-walled arteries because they are able to carry more blood by virtue

neg: Renal vein directly into the IVC. Often, each renal vein will have a branch that receives blood from the ureter. It is usually singular to each kidney, except in the condition "multiple renal veins". In some people the left renal vein passes behind the abdominal aorta instead of in front of it, this is termed a retroaortic left renal vein, which is also known as "The Vein of Schnitker." If there is both a vein passing in front of and one behind the aorta this is called a circumaortic renal vein. Diseases associated with the renal vein include renal vein thrombosis (RVT)

neg: Azotemia in diagnosis. In pre-renal and post-renal azotemias, elevation of the BUN exceeds that of the creatinine (i.e., BUN>12*creatinine). This is because BUN is readily absorbed while creatinine is not. In congestive heart failure (a cause of pre-renal azotemia) or any other condition that causes poor perfusion of kidneys, the sluggish flow of glomerular filtrate results in excessive absorption of BUN and elevation of its value in blood. Creatinine, however, is not absorbable and therefore does not rise significantly. Stasis of urine in post-renal azotemia has the same effect. Azotemia has three classifications, depending on its causative origin: prerenal azotemia, renal

neg: Hemodynamics forces (e.g., during standing), and valves in veins, breathing, and pumping from contraction of skeletal muscles also influence blood pressure in veins. The relationship between pressure, flow, and resistance is expressed in the following equation: When applied to the circulatory system, we get: where A simplified form of this equation assumes right atrial pressure is approximately 0: The ideal blood pressure in the brachial artery, where standard blood pressure cuffs measure pressure, is <120/80 mmHg. Other major arteries have similar levels of blood pressure recordings indicating very low disparities among major arteries. In the innominate artery, the average reading is

neg: Anomalous pulmonary venous connection "must" be present, or else the condition is fatal due to a lack of systemic blood flow. In some cases, it can be detected prenatally. There are four variants: Supracardiac (50%): blood drains to one of the innominate veins (brachiocephalic veins) or the superior vena cava; Cardiac (20%), where blood drains into coronary sinus or directly into right atrium; Infradiaphragmatic (20%), where blood drains into portal or hepatic veins; and a mixed (10%) variant. TAPVC can occur with "obstruction", which occurs when the anomalous vein enters a vessel at an acute angle and can cause pulmonary venous hypertension and cyanosis

neg: Doppler ultrasonography time-consuming than other lower-extremity arterial studies. An alternative to Doppler to visualize vessels is B-flow, which digitally highlights weak flow reflectors (mainly red blood cells) while suppressing the signals from the surrounding stationary tissue. It can visualize flowing blood and surrounding stationary tissues simultaneously. Doppler ultrasonography is widely used in renal ultrasonography. Renal vessels are easily depicted by the color Doppler technique in order to evaluate perfusion. Applying spectral Doppler to the renal artery and selected interlobular arteries, peak systolic velocities, resistive index and acceleration curves can be estimated (Figure 4), e.g., peak systolic velocity of the renal artery above

neg: Takayasu's arteritis due to decreased blood flow to the brain. Of note is the function of renal artery stenosis in the causation of high blood pressure: Normally perfused kidneys produce a proportionate amount of a substance called renin. Stenosis of the renal arteries causes hypoperfusion (decreased blood flow) of the juxtaglomerular apparatus, resulting in exaggerated secretion of renin, and high blood levels of aldosterone, eventually leading to water and salt retention and high blood pressure. The neurological symptoms of the disease vary depending on the degree; the nature of the blood vessel obstruction; and can range from lightheadedness to seizures (in severe

neg: Navicular syndrome permanently reduce blood flow to the navicular bone. Because veins are more easily compressed than arteries, blood flow to the bone would be less obstructed than blood flow from the bone. This would cause a buildup of pressure within the navicular bone. The navicular bone, in response to both the increased pressure and overall decreased blood supply, would absorb mineral from its center. Excess tension can also cause exostoses where the ligaments attach to the navicular bone, giving the bone a "canoe" shape. If tension is extreme, the ligaments may actually tear. Recent research has found correlations between "toe-first landing"

neg: Magnetic resonance angiography and the static tissue signal to be small. This either applies to PC-MRA where the phase difference between blood and static tissue is reduced compared to faster flow and to TOF-MRA where the transverse blood magnetization and thus the blood signal are reduced. Contrast agents may be used to increase blood signal – this is especially important for very small vessels and vessels with very small flow velocities that normally show accordingly weak signal. Unfortunately, the use of gadolinium-based contrast media can be dangerous if patients suffer from poor renal function. To avoid these complications as well as eliminate the

neg: Blood vessel body. This is a result of the left and right side of the heart working together to allow blood to flow continuously to the lungs and other parts of the body. Oxygen poor blood enters the right side of the heart through two large veins. Oxygen rich blood from the lungs enters through the pulmonary veins on the left side of the heart into the aorta and then reaches the rest of the body. The capillaries are responsible for allowing the blood to receive oxygen through tiny air sacs in the lungs. This is also the site where carbon dioxide

neg: Nitroglycerin of ischemic heart disease caused by inadequate flow of blood and oxygen to the heart and as a potent antihypertensive agent. Nitroglycerin corrects the imbalance between the flow of oxygen and blood to the heart. At low doses, nitroglycerin dilates veins more than arteries, thereby reducing preload (volume of blood in the heart after filling); this is thought to be its primary mechanism of action. By decreasing preload, the heart has less blood to pump, which decreases oxygen requirement since the heart does not have to work as hard. Additionally, having a smaller preload reduces the ventricular transmural pressure (pressure

neg: Renal vein thrombosis renal tumors, blood flow and other renal pathologies. An alternative is magnetic resonance angiography or MRA. It is non-invasive, fast and avoids radiation (unlike a CT scan) but it is relatively expensive. MRA produces detailed images of the renal blood flow, vesicle walls, the kidneys and any surrounding tissue. An inferior venocavography with selective venography can be used to rule out the diagnoses of RVT. Surgery to remove the clot is possible, but rarely performed. In the past, surgical removal of the renal vein clot was the primary treatment but it is very invasive and many complications can occur. In

neg: Kidney Kidney The kidneys are two bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder. The nephron is the structural and functional unit of the kidney. Each adult kidney contains around 1 million nephrons. The nephron utilizes four processes to alter the blood plasma which flows to it: filtration, reabsorption, secretion, and excretion. The

neg: Extraction ratio of PAH ~1. This is why PAH is used in PAH clearance to estimate renal plasma flow. Note: The "Hepatic Extraction Ratio" is a similar measurement for clearance of a substance(usually a pharmacological drug) by the liver. It is defined as the fraction of drug removed from blood by the liver, and depends on 3 factors— the hepatic blood flow, the uptake into the hepatocytes, and the enzyme metabolic capacity. Examples of drugs with a high hepatic extraction ratio include propranolol, opiates, and lignocaine Extraction ratio Extraction ratio is a measure in renal physiology, primarily used to calculate renal plasma

neg: Hanging typically become engorged and cyanotic (turned blue through lack of oxygen). There will be the classic sign of strangulation, petechiae, little blood marks on the face and in the eyes from burst blood capillaries. The tongue may protrude. Compromise of the cerebral blood flow may occur by obstruction of the carotid arteries, even though their obstruction requires far more force than the obstruction of jugular veins, since they are seated deeper and they contain blood in much higher pressure compared to the jugular veins. Where death has occurred through carotid artery obstruction or cervical fracture, the face will typically be

neg: Bronchial veins veins. Bronchial veins The bronchial veins are small vessels that return blood from the larger bronchi and structures at the roots of the lungs. The right side drains into the azygos vein, while the left side drains into the left superior intercostal vein or the accessory hemiazygos vein. Bronchial veins are thereby part of the bronchial circulation, carrying waste products away from the cells that constitute the lungs. The bronchial veins are counterparts to the bronchial arteries. However, they only carry ~13% of the blood flow of the bronchial arteries. The remaining blood is returned to the heart via the

neg: Ovarian vein syndrome arise more commonly on the left side. The straight angle between the ovarian vein (or testicular vein in males in the case of varicocoele) and the renal vein has been proposed as a cause of decreased blood return. A related diagnosis is "Nutcraker Syndrome" where the left renal vein is described as being compressed between the aorta and the superior mesenteric artery. This is reported to cause collateral flow paths to open up to drain the left kidney i.e. reversed flow (reflux caudally) in the left renal vein. Pelvic Congestion Syndrome, vaginal and vulval varices, lower limb varices are clinical

neg: Diuresis with cellular matter, particularly necrotic sloughing of dead cells. This debris obstructs the flow of filtrate, which results in reduced output of urine. The arterial supply of the nephron is linked to the filtration apparatus (glomerulus), and reduced perfusion leads to reduced blood flow; usually this is the result of pre-renal pathology. The kidney's resorptive mechanisms are particularly energetic, using nearly 100% of the O supplied. Thus, the kidney is particularly sensitive to reduction in blood supply. This phenomenon occurs because renal flow is restored prior to the normal resorption function of the renal tubule. As you can see in

neg: Portal vein lesser omentum, falciform ligament, and those draining the gallbladder wall. The portal vein and hepatic arteries form the liver's dual blood supply. Approximately 75% of hepatic blood flow is derived from the portal vein, while the remainder is from the hepatic arteries. Unlike most veins, the portal vein does not drain into the heart. Rather, it is part of a portal venous system that delivers venous blood into another capillary system, the hepatic sinusoids of the liver. In carrying venous blood from the gastrointestinal tract to the liver, the portal vein accomplishes two tasks: it supplies the liver with metabolic

neg: Bat bats developed in the absence of terrestrial mammal competitors. Enhanced terrestrial locomotion does not appear to have reduced their ability to fly. Bats have an efficient circulatory system. They seem to make use of particularly strong venomotion, a rhythmic contraction of venous wall muscles. In most mammals, the walls of the veins provide mainly passive resistance, maintaining their shape as deoxygenated blood flows through them, but in bats they appear to actively support blood flow back to the heart with this pumping action. Since their bodies are relatively small and lightweight, bats are not at risk of blood flow rushing

neg: Bronchial veins Bronchial veins The bronchial veins are small vessels that return blood from the larger bronchi and structures at the roots of the lungs. The right side drains into the azygos vein, while the left side drains into the left superior intercostal vein or the accessory hemiazygos vein. Bronchial veins are thereby part of the bronchial circulation, carrying waste products away from the cells that constitute the lungs. The bronchial veins are counterparts to the bronchial arteries. However, they only carry ~13% of the blood flow of the bronchial arteries. The remaining blood is returned to the heart via the pulmonary

neg: PAH clearance flow (eRPF). However, since the renal extraction ratio of PAH almost equals 1, then eRPF almost equals RPF. The renal extraction ratio of PAH in a normal individual is approximately 0.92, and thus not exactly 1.0. Thus, this method usually underestimates RPF by approximately 10%. This margin of error is generally acceptable considering the ease with which eRPF is measured. PAH clearance Para-aminohippurate (PAH) clearance is a method used in renal physiology to measure renal plasma flow, which is a measure of renal function. PAH is completely removed from blood that passes through the kidneys (PAH undergoes both glomerular filtration

neg: Extraction ratio Extraction ratio Extraction ratio is a measure in renal physiology, primarily used to calculate renal plasma flow in order to evaluate renal function. It measures the percentage of the compound entering the kidney that was excreted into the final urine. Measured in concentration in blood plasma, it may thus be expressed as: , where P is the concentration in renal artery, and P is the concentration in the renal vein. For instance, para aminohippuric acid (PAH) is almost completely excreted in the final urine, and thus almost none is found in the venous return (P ~0). Therefore, the extraction ratio

neg: Vein pressure. The arteries are perceived as carrying oxygenated blood to the tissues, while veins carry deoxygenated blood back to the heart. This is true of the systemic circulation, by far the larger of the two circuits of blood in the body, which transports oxygen from the heart to the tissues of the body. However, in pulmonary circulation, the arteries carry deoxygenated blood from the heart to the lungs, and veins return blood from the lungs to the heart. The difference between veins and arteries is their direction of flow (out of the heart by arteries, returning to the heart for

neg: Ultrasonography of chronic venous insufficiency of the legs and show valvular function: Normal blood flow is anterograde (going to the heart), and from superficial to deep veins via perforator veins. However, there are two exceptions: firstly, the great saphenous vein (GSV) collaterals, (the veins that run parallel), drain the abdominal wall and have a flow from top to bottom so that when an examiner tests the sapheno-femoral junction, a false positive diagnosis might be made; secondly, in the flow from the sole of the foot venous network around 10% drains to the dorsal venous arch of the foot, going therefore against the norm, from deep to superficial veins.

neg: Elimination (pharmacology) can be determined on an overall, organism level («systemic clearance») or at an organ level (hepatic clearance, renal clearance etc.). The equation that describes this concept is: formula_1 Where: formula_2 is the organ’s clearance rate, formula_3 is the drug’s plasma concentration in arterial blood, formula_4 is the drug’s plasma concentration in venous blood and formula_5 an organ’s blood flow. Each organ will have its own specific clearance conditions, which will relate to its mode of action. The «renal clearance» rate will be determined by factors such as the degree of plasma protein binding as the drug will only be filtered

neg: Anuria blood pressure. Stones or tumours in the urinary tract can also cause it by creating an obstruction to urinary flow. High blood calcium, oxalate, or uric acid, can contribute to the risk of stone formation. In males, an enlarged prostate gland is a common cause of obstructive anuria. Acute anuria, where the decline in urine production occurs quickly, is usually a sign of obstruction or acute renal failure. Acute renal failure can be caused by factors not related to the kidney, such as heart failure, mercury poisoning, infection, and other conditions that cause the kidney to be deprived of blood

neg: Iatrophysics the heart's heat rather than from contraction. William Harvey postulated blood flow as a closed, continuous loop that run throughout body that contained a certain quantity of blood. To test his claim, Harvey dissected human corpses and animals and, based on his anatomical findings, devised a simple demonstration of how arteries and veins continuously carried blood throughout the body. Taking advantage of the fact that arteries and veins were at different depths below the skin, he tied a person's arm and had them squeeze a bar to shunt blood from arteries to veins, indicating that blood somehow traveled along arteries

neg: Common raven physiology portal system is to regulate renal hemodynamics during times of decreased arterial blood pressure. Kidneys of common ravens receive arterial and afferent venous blood and are drained by efferent veins. In terms of the arterial blood supply, the arteries entering the kidneys branch into numerous smaller arteries and eventually form afferent arterioles that supply the glomeruli. The peritubular blood supply is composed of efferent arterioles leaving the glomeruli of reptilian-type nephrons that drain into sinuses of the cortex. On the other hand, the vasa recta are formed by efferent arterioles exiting the glomeruli of mammalia-type nephrons. Next, the renal portal

neg: Renal vein thrombosis mechanism behind venous thrombosis (blood clots) using three related factors, known as Virchow's Triad; damage to the blood vessel (endothelial damage), decrease in blood flow (stasis) and increased coagulability of the blood (thrombophilia or hypercoagulability). it is possible for one of these factors alone to cause a blood clot, but in most cases, a combination or all of these factors induce the formation of a blood clot. Decreased urine output or kidney function may be the only observable symptoms caused by a blood clot renal vein. Other less common causes include hypercoagulable state, invasion by renal cell carcinoma, kidney transplantation,

neg: Emissary veins passing through the foramen ovale, jugular foramen, foramen lacerum, and hypoglossal canal. Because the emissary veins are valveless, they are an important part in selective brain cooling through bidirectional flow of cooler blood from the evaporating surface of the head. In general, blood flow is from external to internal but the flow can be altered by increased intracranial pressure. A type of emissary vein goes through the sphenoidal emissary foramen inferior to the zygomatic arch with the cavernous sinus on the inside of the skull. This is an important route for spread of infection because cranial nerve VI and the

neg: Ramipril Ramipril Ramipril, sold under the brand name Altace among others, is an angiotensin-converting enzyme (ACE) inhibitor, used to treat high blood pressure (hypertension) and congestive heart failure. By inhibiting an enzyme, ACE inhibitors relax the muscles around small arteries (arterioles). The arterioles expand and allow blood to flow through more easily. This reduces blood pressure. Indications for its use include: Contraindications to its use include renovascular disease (impaired blood flow in the kidneys), severe renal impairment (especially in patients with one kidney or with bilateral renal artery stenosis), volume-depleted patients, a history of angioedema while on an ACE inhibitors, pregnancy,

neg: Renal artery kidneys leading to reduced kidney function and, possibly, renal failure. Renal artery The renal arteries normally arise off the left interior side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle. The renal arteries carry a large portion of total blood flow to the kidneys. Up to a third of total cardiac output can pass through the renal arteries to be filtered by the kidneys. It has a radius of approximately 0.25 cm, 0.26 cm at

neg: Renovascular hypertension improved with surgery. Renovascular hypertension Renovascular hypertension (or "renal hypertension") is a condition in which high blood pressure is caused by the kidneys' hormonal response to narrowing of the arteries supplying the kidneys. When functioning properly this hormonal axis regulates blood pressure. Due to low local blood flow, the kidneys mistakenly increase blood pressure of the entire circulatory system. It is a form of secondary hypertension - a form of hypertension whose cause is identifiable. Symptoms of renovascular hypertension include the following: The cause of renovascular hypertension is consistent with any narrowing/blockage of blood supply to the renal organ (renal

neg: Renovascular hypertension Renovascular hypertension Renovascular hypertension (or "renal hypertension") is a condition in which high blood pressure is caused by the kidneys' hormonal response to narrowing of the arteries supplying the kidneys. When functioning properly this hormonal axis regulates blood pressure. Due to low local blood flow, the kidneys mistakenly increase blood pressure of the entire circulatory system. It is a form of secondary hypertension - a form of hypertension whose cause is identifiable. Symptoms of renovascular hypertension include the following: The cause of renovascular hypertension is consistent with any narrowing/blockage of blood supply to the renal organ (renal artery stenosis). As

neg: Ultrasonography of chronic venous insufficiency of the legs reflux, become damaged and/or incompetent (the dilation of a vein will prevent valves to close properly). This incompetence will result in an reversed blood flow through the affected vein or veins. It can result in varicose veins, and in severe cases venous ulcer. The reversed blood pools in the low third of legs and feet. Unlike the arterial ultrasound study, when the sonographer studies venous insufficiency, the vein wall itself has no relevance and attention will be focused on the direction of blood flow. The objective of the examination is to see how the veins drain. In this way, venous

neg: Pulmonary-renal syndrome polyangiitis is the most common cause of pulmonary-renal syndrome. Other causes include systemic lupus erythematosus, eosinophilic granulomatosis with polyangiitis, microscopic polyangiitis, dermatomyositis, polymyositis, mixed connective tissue disease, poststreptococcal glomerulonephritis, rheumatoid arthritis, and systemic sclerosis. Less common causes also include IgA vasculitis and cryoglobulinemic vasculitis. Other etiologies include toxic injury such as paraquat poisoning, infection with hantavirus, leptospirosis, or legionella, or vascular, as seen in nephrotic syndrome when a renal vein thrombosis embolizes to the lungs. Cardiogenic shock can mimic a pulmonary renal syndrome and lead to coughing up blood due to pulmonary edema and kidney failure from inadequate blood flow.

neg: Indometacin tocolytic agent, able to delay premature labor by reducing uterine contractions through inhibition of prostaglandin synthesis in the uterus and possibly through calcium channel blockade. Indometacin readily crosses the placenta and can reduce fetal urine production to treat polyhydramnios. It does so by reducing renal blood flow and increasing renal vascular resistance, possibly by enhancing the effects of vasopressin on the fetal kidneys. Other modes of action for indometacin are: Indometacin was created in 1963 and it was first approved for use in the U.S. by the Food and Drug Administration in 1965. Its mechanism of action, along with several

neg: Inulin inulin with those of para-aminohippuric acid (PAH). PAH is partially filtered from plasma at the glomerulus and not reabsorbed by the tubules, in a manner identical to inulin. PAH is different from inulin in that the fraction of PAH that bypasses the glomerulus and enters the nephron's tubular cells (via the peritubular capillaries) is completely secreted. Renal clearance of PAH is thus useful in calculation of renal plasma flow (RPF), which empirically is (1-hematocrit) times renal blood flow. Of note, the clearance of PAH is reflective only of RPF to portions of the kidney that deal with urine formation, and,

neg: Ultrasonography of chronic venous insufficiency of the legs Attention will be focused on the direction of the blood flow in both of the venous systems, and in the perforator veins, as well as being focused on shunt detection. A shunting of blood from the thigh veins back into the lower leg veins will give a reflux situation. The veins most often found to be incompetent are the saphenous veins and the perforators communicating with the deep veins of the thigh. Venous ultrasonography of the lower limbs is the most demanding of the medical complementary examinations. It is dependent on the examiner's expertise and training, and the interpretation of

neg: Kidney be confused with interlobular) are between two renal lobes, also known as the renal column (cortex region between two pyramids). The kidney and nervous system communicate via the renal plexus, whose fibers course along the renal arteries to reach each kidney. Input from the sympathetic nervous system triggers vasoconstriction in the kidney, thereby reducing renal blood flow. The kidney also receives input from the parasympathetic nervous system, by way of the renal branches of the vagus nerve; the function of this is yet unclear. Sensory input from the kidney travels to the T10-11 levels of the spinal cord and is

neg: Filtration fraction Filtration fraction In renal physiology, the filtration fraction is the ratio of the glomerular filtration rate (GFR) to the renal plasma flow (RPF). Filtration Fraction, FF = GFR/RPF, or formula_1. The filtration fraction, therefore, represents the proportion of the fluid reaching the kidneys that passes into the renal tubules. It is normally about 20%. GFR on its own is the most common and important measure of renal function. However, in conditions such as renal artery stenosis, blood flow to the kidneys is reduced. Filtration fraction must therefore be increased in order to perform the normal functions of the kidney. Loop

neg: Sickle cell nephropathy Sickle cell nephropathy Sickle cell nephropathy is a type of nephropathy associated with sickle cell disease which causes kidney complications as a result of sickling of red blood cells in the small blood vessels. The hypertonic and relatively hypoxic environment of the renal medulla, coupled with the slow blood flow in the vasa recta, favors sickling of red blood cells, with resultant local infarction (papillary necrosis). Functional tubule defects in patients with sickle cell disease are likely the result of partial ischemic injury to the renal tubules. Also the sickle cell disease in young patients is characterized by renal hyperperfusion,

neg: Renal artery Renal artery The renal arteries normally arise off the left interior side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle. The renal arteries carry a large portion of total blood flow to the kidneys. Up to a third of total cardiac output can pass through the renal arteries to be filtered by the kidneys. It has a radius of approximately 0.25 cm, 0.26 cm at the root. The measured mean diameter can differ depending on

neg: Long-term complications of standing hospitalizations from varicose veins are as a result of prolonged standing. Prolonged standing leads to impeded blood flow and stasis in the veins in the lower limbs, which can cause varicose veins. Standing for prolonged periods can lead to certain cardiovascular disorders. In a study by Krause et al. (2000) the authors examined the relationship between standing at work and the progression of carotid atherosclerosis in men. Standing for long periods can change the distribution of blood in the extremities. This in turn causes the blood to pool and reduces the circulating blood plasma volume leading to hemodynamic changes that

neg: Evolutionary baggage in people living in tropical areas where malaria is prevalent, is a hereditary blood disorder characterized by rigid, sickle-shaped red blood cells.. The unusual shape and rigidity of these altered red blood cells reduces a cell’s ability to effectively travel with regular blood flow, occasionally blocking veins and preventing proper blood flow. Life expectancy is shortened for people with sickle-cell disease, though modern medicine has significantly lengthened the life expectancy of someone with this disease. As detrimental as the effects of sickle-cell disease seem, it also offers an unforeseen benefit; humans with the sickle-cell gene show less severe symptoms when

neg: Blood air to all of the cells of the body, and venous blood carries carbon dioxide, a waste product of metabolism by cells, to the lungs to be exhaled. However, one exception includes pulmonary arteries, which contain the most deoxygenated blood in the body, while the pulmonary veins contain oxygenated blood. Additional return flow may be generated by the movement of skeletal muscles, which can compress veins and push blood through the valves in veins toward the right atrium. The blood circulation was famously described by William Harvey in 1628. In vertebrates, the various cells of blood are made in the

neg: Urodilatin neutral endopeptidase. Urodilatin Urodilatin is a hormone that causes natriuresis through increasing renal blood flow. It is secreted in response to increased mean arterial pressure and increased blood volume from the cells of the distal tubule and collecting duct. It is important in oliguric patients (such as those with acute renal failure and chronic renal failure) as it lowers serum creatinine and increases urine output. Atrial natriuretic peptide (CDD/ANP-99-126) is a hormone system of clinical importance. Urodilatin (CDD/ ANP-95-126) is a homologue natriuretic peptide that differs from CDD/ANP-99-126 which is excreted into the circulation via exocytosis. The prototype of the

neg: Urodilatin Urodilatin Urodilatin is a hormone that causes natriuresis through increasing renal blood flow. It is secreted in response to increased mean arterial pressure and increased blood volume from the cells of the distal tubule and collecting duct. It is important in oliguric patients (such as those with acute renal failure and chronic renal failure) as it lowers serum creatinine and increases urine output. Atrial natriuretic peptide (CDD/ANP-99-126) is a hormone system of clinical importance. Urodilatin (CDD/ ANP-95-126) is a homologue natriuretic peptide that differs from CDD/ANP-99-126 which is excreted into the circulation via exocytosis. The prototype of the natriuretic hormones

neg: Lutembacher's syndrome blood flow of the heart changes; a tissue flap (septum primium) normally closes the hole (foramen ovale) between the two atria and becomes part of the atrial wall. During ASD primium, after birth the hole is not completely closed allowing deoxygenated blood to flow into the left atria from the right atria. With the failure of the blood to pass from the right atrium into the right ventricle and then into the pulmonary veins, blood will not obtain any oxygen before it is leaves the heart and goes to other parts of the body. Due to the incorrect blood flow,

neg: Afferent arterioles Afferent arterioles 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 afferent arterioles later diverge into the capillaries of the glomerulus. When renal blood flow is reduced (indicating hypotension) or there is a decrease in sodium or chloride ion concentration, the macula densa of the distal tubule releases prostaglandins (mainly PGI2 and PGE2) and nitric oxide, which cause

neg: Blood vessel diffuse vascular supply it is called an anastomosis. Anastomoses provide critical alternative routes for blood to flow in case of blockages. There is a layer of muscle surrounding the arteries and the veins which help contract and expand the vessels. This creates enough pressure for blood to be pumped around the body. Blood vessels are part of the circulatory system, together with the heart and the blood. The biggest difference in the structure of arteries and veins is the presence of valves. Backflow of blood is prevented in arteries by the heart. However in veins, one-direction valves are used to

neg: American flamingo gas exchange can occur. Capillaries are organized into capillary beds in tissues, it is here that blood exchanges oxygen for carbon dioxide waste. In the capillary beds blood flow is slowed to allow maximum diffusion of oxygen into the tissues. Once the blood has become deoxygenated it travels through venules then veins and back to the heart. Veins, unlike arteries, are thin and rigid as they do not need to withstand extreme pressure. As blood travels through the venules to the veins a funneling occurs called vasodilation bringing blood back to the heart. Once the blood reaches the heart it

neg: Alpha-1 adrenergic receptor the α-adrenergic receptor, but also has specific effects of its own. α1-receptors primarily mediate smooth muscle contraction, but have important functions elsewhere as well. The neurotransmitter norepinephrine has higher affinity for the α1 receptor than does epinephrine (which is a hormone). In smooth muscle cells of blood vessels the principal effect of activation of these receptors is vasoconstriction. Blood vessels with α-adrenergic receptors are present in the skin, the sphincters of gastrointestinal system, kidney (renal artery) and brain. During the fight-or-flight response vasoconstriction results in decreased blood flow to these organs. This accounts for the pale appearance of the skin

neg: Autoregulation over a range of pressures. This part of coronary circulatory regulation is known as auto regulation and it occurs over a plateau, reflecting the constant blood flow at varying CPP & resistance. The slope of a CBF (coronary blood flow) vs. CPP graph gives 1/Resistance. Regulation of renal blood flow is important to maintaining a stable glomerular filtration rate (GFR) despite changes in systemic blood pressure (within about 80-180 mmHg). In a mechanism called tubuloglomerular feedback, the kidney changes its own blood flow in response to changes in sodium concentration. The sodium chloride levels in the urinary filtrate are sensed

neg: Renal corpuscle Renal corpuscle A renal corpuscle is the blood-filtering component of the nephron of the kidney. It consists of a glomerulus - a tuft of capillaries composed of endothelial cells, and a glomerular capsule known as Bowman's capsule. The renal corpuscle is composed of two structures, the glomerulus and the Bowman's capsule. The glomerulus is a small tuft of capillaries containing two cell types. Endothelial cells, which have large fenestrae, are not covered by diaphragms. Mesangial cells are modified smooth muscle cells that lie between the capillaries. They regulate blood flow by their contractile activity and secrete extracellular matrix, prostaglandins, and

neg: Laminitis radiographic measurements, made on the lateral view, allow for objective evaluation of the episode. Venograms can help determine the prognosis for the animal, particularly in horses where the degree of pain does not match the radiographic changes. In venography, a contrast agent, visible on radiographs, is injected into the palmar digital vein to delineate the vasculature of the foot. The venogram can assess the severity and location of tissue compromise and monitor effectiveness of the current therapy. Compression of veins within the hoof will be seen as sections that do not contain contrast material. Poor or improper blood flow to

neg: Postterm pregnancy rate is typically between 110 and 160 beats per minute. Doppler flow study is a type of ultrasound that measures the amount of blood flowing in and out of the placenta. The ultrasound machine can also detect the direction of blood flow and display it in red or blue. Usually, a red color indicates a flow toward the ultrasound transducer, while blue indicates a flow away from the transducer. Based on the display, doctors can evaluate blood flow to the umbilical arteries, umbilical veins, or other organs such as heart and brain. Nonstress test (NST) is a type of electronic

neg: Mitral valve repair Mitral valve repair Mitral valve repair is a cardiac surgery procedure performed by cardiac surgeons to treat stenosis (narrowing) or regurgitation (leakage) of the mitral valve. The mitral valve is the "inflow valve" for the left side of the heart. Blood flows from the lungs, where it picks up oxygen, through the pulmonary veins, to the left atrium of the heart. After the left atrium fills with blood, the mitral valve allows blood to flow from the left atrium into the heart's main pumping chamber called the left ventricle. It then closes to keep blood from leaking back into the

neg: Smallest cardiac veins They drain the myocardium and run a perpendicular course to the endocardial surface, directly connecting the heart chambers to the medium-sized, and larger coronary veins. Thebesian veins have been successfully identified by following the route of contrast flow - during catheterization procedures - from the subendocardium, through the thebesian veins, into larger veins, and into the coronary sinus. The coronary sinus empties into the right atrium. The thebesian venous network is considered an alternative venous drainage of the myocardium. Thebesian veins draining into the left heart, along with deoxygenated blood originating from the bronchial veins draining into the pulmonary veins,

neg: Hieronymus Fabricius to describe the membranous folds that he called "valves" in the interior of veins. These valves are now understood to prevent retrograde flow of blood within the veins, thus facilitating antegrade flow of blood towards the heart, though Fabricius did not understand their role at that time. In his "Tabulae Pictae", first published in 1600, Fabricius described the cerebral fissure separating the temporal lobe from the frontal lobe. However, Fabricius' discovery was not recognized until recently. Instead, Danish anatomist Caspar Bartholin credits Franciscus Sylvius with the discovery, and Bartholin's son Thomas named it the Sylvian fissure in the 1641 edition

neg: Preload (cardiology) Preload can still be approximated by the inexpensive echocardiographic measurement end diastolic volume or EDV. Preload increases with exercise (slightly), increasing blood volume (overtransfusion, polycythemia) and neuroendocrine excitement (sympathetic tone). An arteriovenous fistula can increase preload. Preload is also affected by two main body "pumps": Respiratory pump - Intrapleural pressure decreases during inspiration and abdominal pressure increases, squeezing local abdominal veins, allowing thoracic veins to expand and increase blood flow towards the right atrium. Skeletal muscle pump - In the deep veins of the legs, surrounding muscles squeeze veins and pump blood back towards the heart. This occurs most notably

neg: Infusion pump machines that make plastic soft-drink bottles and caps. A pressure bottle, restrictor and chamber requires more nursing attention than electronically controlled pumps. In the areas where these are used, nurses are often volunteers, or very inexpensive. The restrictor and high pressure helps control the flow better than the improvised schemes because the high pressure through the small restrictor orifice reduces the variation of flow caused by patients' blood pressures. An air filter is an essential safety device in a pressure infusor, to keep air out of the patients' veins. Small bubbles could cause harm in arteries, but in the veins

neg: Shechita dominant hand. The procedure is done with the intention of causing a rapid drop in blood pressure in the brain and loss of consciousness, to render the animal insensitive to pain and to exsanguinate in a prompt and precise action. However, severing the carotid arteries and jugular veins does not cut blood flow to the brain of a bovine, because the brain is supplied with blood also by vertebral arteries. If one did not sever the entirety of both the trachea and esophagus, then an animal may still be considered kosher as long as one severed the majority of the

neg: Thrombosis smooth muscle cells to cover the clot, and this layer of mural smooth muscle will be vascularised by the blood inside the vessel lumen rather than by the vasa vasorum. Ischaemia/infarction: if an arterial thrombus cannot be lysed by the body and it does not embolise, and if the thrombus is large enough to impair or occlude blood flow in the involved artery, then local ischaemia or infarction will result. A venous thrombus may or may not be ischaemic, since veins distribute deoxygenated blood that is less vital for cellular metabolism. Nevertheless, non-ischaemic venous thrombosis may still be problematic, due

neg: Compression stockings own. The formation of varicose veins is an externally visible sign of venous weakness. Deep vein thrombosis occurs when blood flow decreases (especially in the lower extremities), causing blood to pool in the legs and leading to blood clot (thrombus) formation. Evidence does not suggest a benefit in post thrombotic syndrome rates following DVT. Compression stockings are beneficial in reducing symptomless deep vein thrombosis among airline passengers flying for 7 hours or more. Pharmacological (warfarin, unfractionated heparin, low molecular weight heparin) and mechanical measures (graded compression stockings, intermittent pneumatic compression devices, and venous foot pumps) are used to prevent venous

neg: Renal vein thrombosis in the blood, damaging the endothelial tissue and increasing the likelihood of RVT. The most common cause of RVT in infants is dehydration. Dehydration may be caused by reduction in both volume and circulatory blood volume due to water depleting abnormalities like diarrhea or vomiting. The decrease in blood volume due to dehydration will cause blood flow to be diverted away from the kidneys to other organs, resulting in slower blood flow to the kidneys, increasing chances of a blood clot occurrence. "RVT is known to occur in the absence of clinically obvious shock e.g. following neonatal distress and placement

neg: Renal angina the developed world occurs most commonly as a secondary injury to numerous disease processes. Sepsis and cardiopulmonary bypass (CPB) are the most oft recognized and reported “causative” injuries leading to AKI. The pathophysiology of AKI can be broadly categorized into four main categories: ischemic injury – manifest by low glomerular blood flow or perfusion pressure to the renal capillary system, hypoxic injury to the renal interstitium, inflammation of the renal tubules, or necrosis and apoptosis of the renal parenchyma. There is increasing recognition that people are not just dying "with" AKI, but "from" AKI. The epidemiology of AKI has changed