Edema, Fainting, and Strokes

2021 ◽  
pp. 216-240
Author(s):  
Graham Mitchell
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Fluid Pressure ◽  
Basement Membranes ◽  
Tissue Pressure ◽  
Efficient Mechanisms ◽  
The Brain ◽  
Mediated Reduction

High blood pressure in humans is often associated with heart failure, edema, strokes, and episodes of fainting. Giraffes never show these. Edema, the abnormal collection of fluid in the lower legs, is prevented in giraffes by a combination of thick basement membranes of capillary blood vessels, which probably reduce their permeability to proteins, a very high tissue pressure that resists flow of fluid out of capillaries, and efficient mechanisms for returning blood to the heart. Fainting occurs when blood flow (and thus oxygen and glucose supply) to the brain is reduced. When a giraffe lifts its head after drinking water there is a sudden reduction of blood flow to the head, and fainting should result. Fainting is avoided because the blood flow that remains is diverted completely to the brain by a unique arrangement of blood vessels and nerves, and by structures that maintain the perfusion pressure of the blood flowing through the brain. Strokes can be caused by rupture of small blood vessels in the brain when they are exposed to high blood pressure of the kind reached in the head of a giraffe when it drinks surface water. Rupture of brain blood vessels is prevented in giraffes by mechanisms that reduce pressure. The posture adopted while drinking, baroreceptor-mediated reduction in cardiac output, the effects of the carotid rete, diversion of blood away from the brain, an increase in cerebrospinal fluid pressure, and passive and active constriction of blood vessels, all contribute.

COMPARISON OF ANTIHYPERTENSIVE EFFECT OF MOXONIDINE VERSUS CLONIDINE IN RENAL FAILURE PATIENTS.

2018 ◽  
Vol 6 (9) ◽  
Author(s):  
DR.MATHEW GEORGE ◽  
DR.LINCY JOSEPH ◽  
MRS.DEEPTHI MATHEW ◽  
ALISHA MARIA SHAJI ◽  
BIJI JOSEPH ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Failure ◽  
Blood Flow ◽  
Blood Vessel ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Antihypertensive Effect ◽  
The Body ◽  
Ability To Work ◽  
Blood Flows

Blood pressure is the force of blood pushing against blood vessel walls as the heart pumps out blood, and high blood pressure, also called hypertension, is an increase in the amount of force that blood places on blood vessels as it moves through the body. Factors that can increase this force include higher blood volume due to extra fluid in the blood and blood vessels that are narrow, stiff, or clogged(1). High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. When the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually, this stretching scars and weakens blood vessels throughout the body, including those in the kidneys.

Buckling Behavior of Arteries Under Torsion

2011 ◽  
Author(s):  
Justin R. Garcia ◽  
Shawn D. Lamm ◽  
Hai-Chao Han
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Atherosclerotic Plaque ◽  
Vascular Grafts ◽  
Vascular Diseases ◽  
The Body ◽  
Buckling Behavior ◽  
Surgical Implantation

Arterial tortuosity is a phenomenon which is observed throughout the body and is associated with aging, diabetes, high blood pressure, and other vascular diseases [1]. Tortuous arteries significantly hinder blood flow which may lead to the development of atherosclerotic plaque buildup [2]. Blood vessels may also become twisted or demonstrate 3-D tortuous shapes when subject to large twist deformations such as during surgical implantation of vascular grafts, propeller flap procedures, stent-artery interactions, and sudden movements of the neck or limbs [4–6]. However, the twisting behavior of arteries is poorly understood.

Living Well to Keep Your Pressure Down

EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
Linda B. Bobroff
Keyword(s):  
Risk Factors ◽  
Blood Pressure ◽  
Blood Vessels ◽  
High Blood Pressure ◽  
Health Problems ◽  
Fact Sheet ◽  
Living Well ◽  
Heart Work ◽  
Major Revision ◽  
Reduce Risk

High blood pressure, or hypertension, can cause serious health problems. It makes your heart work harder and can damage your blood vessels even if you feel okay. Everyone should have their blood pressure checked regularly. If you have certain risk factors, you are more likely to have high blood pressure. This 6-page fact sheet is a major revision that discusses risk factors and ways to reduce risk.

scholarly journals Is High Blood Pressure Self-Protection for the Brain?

2016 ◽  
Vol 119 (12) ◽  
Author(s):  
Esther A.H. Warnert ◽  
Jonathan C.L. Rodrigues ◽  
Amy E. Burchell ◽  
Sandra Neumann ◽  
Laura E.K. Ratcliffe ◽  
...  
Keyword(s):  
Blood Pressure ◽  
High Blood Pressure ◽  
Self Protection ◽  
The Brain

Intraventricular injection of antibodies to β1-integrins generates pressure gradients in the brain favoring hydrocephalus development in rats

2009 ◽  
Vol 297 (5) ◽  
pp. R1312-R1321 ◽  
Author(s):  
Gurjit Nagra ◽  
Lena Koh ◽  
Isabelle Aubert ◽  
Minhui Kim ◽  
Miles Johnston
Keyword(s):  
Fluid Pressure ◽  
Active Role ◽  
Intraventricular Injection ◽  
Pressure Gradients ◽  
Tissue Pressure ◽  
Before And After ◽  
The Matrix ◽  
System 2 ◽  
Periventricular Area ◽  
The Brain

In some tissues, the injection of antibodies to the β1-integrins leads to a reduction in interstitial fluid pressure, indicating an active role for the extracellular matrix in tissue pressure regulation. If perturbations of the matrix occur in the periventricular area of the brain, a comparable lowering of interstitial pressures may induce transparenchymal pressure gradients favoring ventricular expansion. To examine this concept, we measured periventricular (parenchymal) and ventricular pressures with a servo-null micropipette system (2-μm tip) in adult Wistar rats before and after anti-integrin antibodies or IgG/IgM isotype controls were injected into a lateral ventricle. In a second group, the animals were kept for 2 wk after similar injections and after euthanization, the brains were removed and assessed for hydrocephalus. In experiments in which antibodies to β1-integrins ( n = 10) but not isotype control IgG/IgM ( n = 7) were injected, we observed a decline in periventricular pressures relative to the preinjection values. Under similar circumstances, ventricular pressures were elevated ( n = 10) and were significantly greater than those in the periventricular interstitium. We estimated ventricular to periventricular pressure gradients of up to 4.3 cmH2O. In the chronic preparations, we observed enlarged ventricles in many of the animals that received injections of anti-integrin antibodies (21 of 29 animals; 72%) but not in any animal receiving the isotype controls. We conclude that modulation/disruption of β1-integrin-matrix interactions in the brain generates pressure gradients favoring ventricular expansion, suggesting a novel mechanism for hydrocephalus development.

Control of Blood Pressure and the Distribution of Blood Flow

1991 ◽  
Vol 7 (S1) ◽  
pp. 79-84 ◽  
Author(s):  
Hans T. Versmold
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Peripheral Resistance ◽  
Systemic Blood Pressure ◽  
Adrenergic Innervation ◽  
Systemic Blood ◽  
Low Cardiac Output ◽  
Neurohumoral Control ◽  
The Brain

Systemic blood pressure (BP) is the product of cardiac output and total peripheral resistance. Cardiac output is controlled by the heart rate, myocardial contractility, preload, and afterload. Vascular resistance (vascular hindrance × viscosity) is under local autoregulation and general neurohumoral control through sympathetic adrenergic innervation and circulating catecholamines. Sympathetic innovation predominates in organs receivingflowin excess of their metabolic demands (skin, splanchnic organs, kidney), while innervation is poor and autoregulation predominates in the brain and heart. The distribution of blood flow depends on the relative resistances of the organ circulations. During stress (hypoxia, low cardiac output), a raise in adrenergic tone and in circulating catecholamines leads to preferential vasoconstriction in highly innervated organs, so that blood flow is directed to the brain and heart. Catecholamines also control the levels of the vasoconstrictors renin, angiotensin II, and vasopressin. These general principles also apply to the neonate.

Vasodilation of cat cerebral arterioles by prostaglandins D2, E2, G2, and I2

1979 ◽  
Vol 237 (3) ◽  
pp. H381-H385 ◽  
Author(s):  
E. F. Ellis ◽  
E. P. Wei ◽  
H. A. Kontos
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Blood Pressure ◽  
Standard Error ◽  
Arterial Blood ◽  
Cerebral Arterioles ◽  
The Mean ◽  
Dose Dependent ◽  
The Brain

To determine the possible role that endogenously produced prostaglandins may play in the regulation of cerebral blood flow, the responses of cerebral precapillary vessels to prostaglandins (PG) D2, E2, G2, and I2 (8.1 X 10(-8) to 2.7 X 10(-5) M) were studied in cats equipped with cranial windows for direct observation of the microvasculature. Local application of PGs induced a dose-dependent dilation of large (greater than or equal to 100 microns) and small (less than 100 microns) arterioles with no effect on arterial blood pressure. The relative vasodilator potency was PGG2 greater than PGE2 greater than PGI2 greater than PGD2. With all PGs, except D2, the percent dilation of small arterioles was greater than the dilation of large arterioles. After application of prostaglandins in a concentration of 2.7 X 10(-5) M, the mean +/- standard error of the percent dilation of large and small arterioles was, respectively, 47.6 +/- 2.7 and 65.3 +/- 6.1 for G2, 34.1 +/- 2.0, and 53.6 +/- 5.5 for E2, 25.4 +/- 1.8, and 40.2 +/- 4.6 for I2, and 20.3 +/- 2.5 and 11.0 +/- 2.2 for D2. Because brain arterioles are strongly responsive to prostaglandins and the brain can synthesize prostaglandins from its large endogenous pool of prostaglandin precursor, prostaglandins may be important mediators of changes in cerebral blood flow under normal and abnormal conditions.

119 Visualization of Vascular Structures of the Brain Through a Novel Multispectral Fluorescence Microscope After Intravenous Application of ICG

Neurosurgery ◽  
2017 ◽  
Vol 64 (CN_suppl_1) ◽  
pp. 226-226
Author(s):  
Dimitrios Athanasopoulos
Keyword(s):  
Blood Flow ◽  
Blood Vessels ◽  
Intravenous Injection ◽  
White Light ◽  
Surgical Microscope ◽  
Light Image ◽  
Fluorescent Image ◽  
Surgical Clip ◽  
Vascular Structures ◽  
The Brain

Abstract INTRODUCTION Vascular structures are intraoperatively visualized through the eye-piece of a surgical microscope. The blood flow within the blood vessels can be demonstrated via indocyanine green (ICG) fluorescence. In this study we wanted to find out whether the development of a novel fluorescent surgical microscope, overlapping a multispectral fluorescent image on a white light image, is superior, equal or inferior, compared to the previous models. Moreover, it shall be proved, whether multispectral fluorescence enhances surgeon's orientation through the precise and clearer visualization of blood vessels and the blood flow. METHODS A total of 8 porcine animal models were used. After fixation of the animal's head the parietal cortex and the cortical blood vessels were exposed. A digital imaging of the arterial perfusion, capillary transition and venous drainage after intravenous injection of ICG (5 ml; 5 mg/ml) was then performed. The blood flow was artificially blocked by a surgical clip. After repetitive intravenous injection of ICG and visualisation with multispectral view, the surgical clip was removed and the reperfusion of the brain tissue was visualized with the real time ICG perfusion. RESULTS >The visualization of the anatomical structures of the surgical field under white light as well as the image overlapping were easily performed. The occlusion of blood vessels with surgical clips demonstrate a blockage of the ICG perfusion on the multispectral fluorescent image. The ICG perfusion was again demonstrated after removing the surgical clip and reperfusion of the blood vessel. CONCLUSION Multispectral fluorescence was shown to be superior to the classic ICG fluorescence. With the development of a novel multispectral surgical microscope, which overlaps a fluorescent image on a white light image, the data delivered to the surgeon are enhanced, compared to the previous models. Moreover, the surgeons's orientation is improved thanks to the clear visualization of blood vessels and the blood flow.

Respiratory muscle and organ blood flow with inspiratory elastic loading and shock

1985 ◽  
Vol 58 (4) ◽  
pp. 1148-1156 ◽  
Author(s):  
S. Magder ◽  
D. Lockhat ◽  
B. J. Luo ◽  
C. Roussos
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Respiratory Muscle ◽  
Respiratory Muscles ◽  
Organ Blood Flow ◽  
Normal Blood Pressure ◽  
Elastic Load ◽  
Severe Hypotension ◽  
Elastic Loading ◽  
The Brain

Since respiratory muscles fail when blood flow is inadequate, we asked whether their blood flow would be maintained in severe hypotensive states at the expense of other vital organs (brain, heart, kidney, gut, spleen). We measured blood flow (radiolabeled microspheres) to respiratory muscles and vital organs in 11 dogs breathing against an inspiratory elastic load, first with normal blood pressure (BP) and then hypotension produced by cardiac tamponade. With the elastic load alone, there was no change in BP or cardiac output; diaphragmatic blood flow (Qdi) increased from 12.8 +/- 7.0 to 34.1 +/- 15.6 ml/100 g, and total respiratory muscle flow (QTR) increased from 56.5 +/- 19.1 to 97.4 +/- 36.5 ml/100 g, but except for the brain, there was no change in blood flow to other organs. With tamponade (mean BP = 79 +/- 16 mmHg), flow decreased to all organs, whereas Qdi (39.0 +/- 19.4) did not change. QTR decreased, but not significantly, to 88.6 +/- 49.5. With more tamponade (mean BP = 53 +/- 13 mmHg), flow to all vital organs decreased as well as QTR (57.9 +/- 47.18), but Qdi did not significantly decrease and had the same relationship to respiratory force as with normal BP. Thus, with severe inspiratory elastic loading and severe hypotension, the diaphragm and external intercostal muscles did most of the respiratory work, and their flow was maintained at the expense of other vital organs.

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