5. Blood pressure and blood flow

2016 ◽  
pp. 83-102
Author(s):  
Chris Cooper
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Driving Force ◽  
Beta Blockers ◽  
Venous Blood ◽  
The Body ◽  
Chronic Hypertension ◽  
Arterial Blood ◽  
Lifestyle Choices

The heart is the organ that pumps blood around the body. If the heart stops functioning, blood does not flow. The driving force for this flow is the pressure difference between the arterial blood leaving the heart and the returning venous blood. ‘Blood pressure and blood flow’ first considers how blood pressure is measured and how blood pressure can affect health. High blood pressure is called hypertension and low blood pressure hypotension. Chronic hypertension has serious long-term adverse health consequences, but can be treated with improved lifestyle choices and a range of medicines, including anti-hypertensive drugs, beta blockers, and ACE inhibitor drugs. The different molecules affecting blood flow are also considered.

Oxygen consumption and blood flow in the hypothermic, perfused kidney

1959 ◽  
Vol 197 (5) ◽  
pp. 1111-1114 ◽  
Author(s):  
Matthew N. Levy
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Blood Viscosity ◽  
The Body ◽  
Peripheral Artery ◽  
Isolated Kidney ◽  
Arterial Blood ◽  
Oxygen Difference ◽  
Appreciable Reduction

Temperature was diminished in a stepwise fashion in the isolated kidney of the dog perfused from a peripheral artery of the original, normothermic animal. Decreased temperature resulted in an appreciable reduction of renal blood flow at constant arterial blood pressure. Increased blood viscosity and vasoconstriction were both responsible for this reduction of flow. Hypothermia also resulted in a reduction in arteriovenous oxygen difference which was roughly proportional to the centigrade temperature. Furthermore, hypothermia exerted a marked but reversible depression of the rate of oxidative metabolism. This effect was relatively more severe than the changes for the body as a whole at equivalent temperatures reported by other investigators.

Adrenal catecholamines in E. coli endotoxin shock

1961 ◽  
Vol 16 (2) ◽  
pp. 348-350 ◽  
Author(s):  
Florian Nykiel ◽  
Vincent V. Glaviano
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Venous Blood ◽  
Endotoxin Shock ◽  
Mean Blood Pressure ◽  
E Coli ◽  
Arterial Blood ◽  
Splanchnic Nerves

In dogs with left adrenal cannulation, administration of 1 mg/kg of purified E. coli endotoxin resulted in a decrease in mean blood pressure and adrenal blood flow. These changes were accompanied by significant increases in levels of epinephrine in adrenal venous blood. Release of epinephrine by the adrenals in endotoxin shock was due to a neurogenic mechanism, since sectioning of the splanchnic nerves prevented secretion of epinephrine. The rise in epinephrine output from an intact adrenal was noted to occur only in the presence of a significant decrease in arterial blood pressure; therefore endotoxin causes adrenal stimulation from reflexes initiated by the hypothalamus or peripheral baroreceptors. Submitted on September 20, 1960

Response to cold of Eskimos of the eastern Canadian Arctic

1963 ◽  
Vol 18 (5) ◽  
pp. 970-974 ◽  
Author(s):  
G. Malcolm Brown ◽  
Robert E. Semple ◽  
C. S. Lennox ◽  
G. S. Bird ◽  
C. W. Baugh
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Canadian Arctic ◽  
The Body ◽  
Arterial Blood ◽  
Acute Cold Exposure ◽  
Body Core ◽  
Average Skin ◽  
Skin Temperatures ◽  
Eastern Canadian Arctic

Skin, muscle, and rectal temperatures, and O2 consumption of Eskimos and Caucasians have been compared during an acute cold exposure involving immersion of one hand and forearm in a 5 C water bath. The Eskimos consumed less O2, maintained their rectal temperatures at a higher level, and gave up less heat from the muscles of the limbs. Though the Eskimos had significantly more adipose tissue, average skin temperatures were the same in the two groups. The pattern of temperatures noted now and the previously observed higher blood flow in the hand and forearm of Eskimos point to increased cooling of arterial blood by returning venous blood in the extremities with resultant preservation of heat in the body core. Submitted on August 6, 1962

scholarly journals Blood pressure and blood flow variation during postural change from sitting to standing: model development and validation

2005 ◽  
Vol 99 (4) ◽  
pp. 1523-1537 ◽  
Author(s):  
Mette S. Olufsen ◽  
Johnny T. Ottesen ◽  
Hien T. Tran ◽  
Laura M. Ellwein ◽  
Lewis A. Lipsitz ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Mathematical Model ◽  
Blood Flow ◽  
Young Subject ◽  
Venous Blood ◽  
Cardiovascular Responses ◽  
Physiological Data ◽  
Postural Change ◽  
Metabolic Demand ◽  
Arterial Blood

Short-term cardiovascular responses to postural change from sitting to standing involve complex interactions between the autonomic nervous system, which regulates blood pressure, and cerebral autoregulation, which maintains cerebral perfusion. We present a mathematical model that can predict dynamic changes in beat-to-beat arterial blood pressure and middle cerebral artery blood flow velocity during postural change from sitting to standing. Our cardiovascular model utilizes 11 compartments to describe blood pressure, blood flow, compliance, and resistance in the heart and systemic circulation. To include dynamics due to the pulsatile nature of blood pressure and blood flow, resistances in the large systemic arteries are modeled using nonlinear functions of pressure. A physiologically based submodel is used to describe effects of gravity on venous blood pooling during postural change. Two types of control mechanisms are included: 1) autonomic regulation mediated by sympathetic and parasympathetic responses, which affect heart rate, cardiac contractility, resistance, and compliance, and 2) autoregulation mediated by responses to local changes in myogenic tone, metabolic demand, and CO2 concentration, which affect cerebrovascular resistance. Finally, we formulate an inverse least-squares problem to estimate parameters and demonstrate that our mathematical model is in agreement with physiological data from a young subject during postural change from sitting to standing.

Renal Response to Nonshocking Hemorrhage: the Role of Intrarenal Shunts

1958 ◽  
Vol 193 (2) ◽  
pp. 360-364 ◽  
Author(s):  
Allan V. N. Goodyer ◽  
Louis R. Mattie ◽  
Allen Chetrick
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Body Weight ◽  
Arterial Pressure ◽  
The Body ◽  
Arterial Blood ◽  
Anesthetized Dogs ◽  
Renal Innervation ◽  
Aortic Obstruction

In anesthetized dogs, bleeding (1.5–3% of the body weight) was allowed while renal arterial pressure was maintained at constant levels by graded changes of mechanical aortic obstruction. The renal hematocrit decreased, (as measured with I131 albumin and acid hematin, and as compared to the blood hematocrit), primarily as a result of an increased renal plasma volume. These changes are correlated with previously identified alterations of sodium excretion, all independent of renal innervation or arterial blood pressure. It is proposed that hemorrhage may involve an intrarenal redistribution of blood flow favoring diversion of plasma to cell-poor capillaries or to lymphatic spaces.

scholarly journals Long-Term Effect of an AqueousFraxinus excelsiorL. Seed Extract in Spontaneously Hypertensive Rats

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Noemi López-Carreras ◽  
Sandra Fernández-Vallinas ◽  
Marta Miguel ◽  
Amaya Aleixandre
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Spontaneously Hypertensive Rats ◽  
Seed Extract ◽  
The Body ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Arterial Blood ◽  
Plasma Antioxidant Capacity

The effect of long-term intake of different doses (20, 40, and 60 mg/kg/day) of aFraxinus excelsiorL. seed extract (FESE) on spontaneously hypertensive rats (SHR) was evaluated. Water was used as control and captopril (50 mg/kg/day) was used as positive control. Systolic blood pressure, body weight, and food and liquid intake were registered weekly in SHR. The antioxidant and vascular relaxing properties of FESE were also studied in these animals. The development of hypertension was attenuated in the groups treated with captopril or FESE. The antihypertensive effect was more accentuated in the captopril group than in the FESE groups, and it was paradoxically more accentuated in the groups treated with 20 mg/kg/day or 40 mg/kg/day of FESE than in the group treated with the highest dose of this extract. Body weight gain and food intake increased in the FESE groups. After removing the corresponding antihypertensive treatment, the arterial blood pressure and the body weight of the FESE treated animals returned to control values. In addition, FESE increased plasma antioxidant capacity and decreased plasma and liver malondialdehyde levels. Moreover, acetylcholine relaxation improved in the aorta rings from the FESE treated rats.

scholarly journals Effect of Electrical Stimulation on Blood Flow in Calf Muscles in Different Body Positions

2018 ◽  
Vol 1 (96) ◽  
Author(s):  
Julius Dovydaitis ◽  
Albinas Grūnovas
Keyword(s):  
Blood Flow ◽  
Body Position ◽  
Venous Blood ◽  
The Body ◽  
Arterial Blood Flow ◽  
Reserve Capacity ◽  
Horizontal Position ◽  
Blood Flows ◽  
Arterial Blood ◽  
Electrical Muscle

Background.  In  most  studies  on  cardiovascular  system,  testing  of  subjects  was  performed  in  a  horizontal position. With the change of the body position, certain functional changes occur in the cardiovascular system. The aim of this study was to analyze the effect of electrical muscle stimulation (EMS) on arterial and venous blood flows.Methods. Eighteen athletes aged 19–23 performed two sessions of tests in horizontal and sitting positions. Changes in arterial and venous blood flows were recorded before and after EMS. In each session two occlusions were performed. In the horizontal position, the initial occlusion pressure of 20 mmHg was applied and as the balance in arterial and venous blood flow rates was reached, the additional pressure of 20 mmHg (40  mmHg in total). In the sitting position, the occlusion pressure of 40 and 20 mmHg was applied respectively (60 mmHg in total). In both sessions EMS was performed using the electrical stimulator Mioritm 021.Results. In both horizontal and vertical positions, the effect of EMS on arterial blood flow, venous reserve capacity and venous elasticity was insignificant. Arterial and venous blood flows was affected significantly by the change of the body position. In the sitting position, arterial blood flow was significantly (p < .05) lower compared to the horizontal position. Similar results were recorded in venous reserve capacity.Conclusion.  The  study  suggests  that  blood  flow  in  the  calf  muscles  is  affected  by  the  body  position  and hydrostatic pressure; arterial blood flow increases in the horizontal body position.Keywords:  electrical muscle stimulation (EMS), arterial blood flow, venous reserve capacity, venous elasticity

Blood-Pressure in Cardiazol Epilepsy

1939 ◽  
Vol 85 (357) ◽  
pp. 787-795 ◽  
Author(s):  
E. Guttmann ◽  
F. Reitmann
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Chemical Analysis ◽  
Human Brain ◽  
Histological Examination ◽  
Venous Blood ◽  
The Body ◽  
Cerebral Vessels ◽  
The Subject ◽  
Recent Monograph

No problem in neurology has been approached from so many different angles as has the pathogenesis of the epileptic fit; yet it is far from being solved. Histological examination of the brains of epileptics, electric stimulalation of the human brain during operation, chemical analysis of the body fluids both in general and of the arterial and venous blood of the cerebral vessels in particular, measurements of the intracranial blood-flow, investigations into metabolic changes before, during, and after fits, electro-encephalographic studies, have produced an enormous wealth of data, which it has not, however, been possible to weld into a single theory. The most recent monograph on epilepsy—Kinnier Wilson's article on the subject in Bumke's Handbuch der Neurologie—speaks only of various “determinants” of the fit: the vascular, the humoral, etc.

Failure of acute saralasin to reverse chronic hypertension in fetal lambs

1991 ◽  
Vol 260 (4) ◽  
pp. R811-R816
Author(s):  
D. F. Anderson ◽  
N. D. Binder
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Upper Body ◽  
Chronic Hypertension ◽  
Aortic Blood Flow ◽  
Flow Reduction ◽  
Arterial Blood ◽  
Aortic Blood ◽  
Blood Flow Reduction

Upper body arterial hypertension developed in 12 fetal lambs after chronic suprarenal aortic blood flow reduction. Sixty minutes after blood flow reduction, intravenous saralasin infusion was able to reduce upper body mean arterial blood pressure to control levels. Although saralasin infusion was able to decrease upper body arterial blood pressure after 1 day of hypertension, it was not able to return blood pressure to control levels. Three or more days later, saralasin was unable to cause a significant reduction in upper body arterial blood pressure. We conclude that, although the renin-angiotensin system has a role in maintaining the elevated blood pressure after greater than or equal to 1 day of suprarenal aortic blood flow reduction, some other mechanism also participates. We have ruled out a role for changing blood volume, and our results suggest that an elevation of plasma catecholamines is not responsible. Some other pathway for fluid regulation available to the fetus may be responsible.

The Brain as Contributor of Plasminogen Activator to the Blood

1970 ◽  
Vol 38 (1) ◽  
pp. 85-91 ◽  
Author(s):  
I. Sudhakaran Menon ◽  
J. Muscat-Baron ◽  
D. Weightman ◽  
H. A. Dewar
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Human Brain ◽  
Plasminogen Activator ◽  
Considerable Increase ◽  
Jugular Vein ◽  
Venous Blood ◽  
The Body ◽  
Arterial Blood ◽  
The Brain

1. A considerable increase in the plasminogen activator content in the internal jugular venous blood as compared with that in the arterial blood was found in fifty patients. 2. Inhalation of 5% carbon dioxide in air was associated with increased plasminogen activator content in blood from the internal jugular vein in all the eight patients treated in this way. 3. It is suggested that the human brain makes a contribution of plasminogen activator to the circulation of the body and that the amount contributed is determined by the rate of the blood flow.

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