Cardiovascular system

2011 ◽  
pp. 443-462
Author(s):  
Dr Mark Harrison
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Cardiovascular System ◽  
Cardiac Cycle ◽  
Peripheral Circulation ◽  
Pharmacological Manipulation ◽  
System P

2.1 Control of blood pressure and heart rate, 445 2.2 Control of heart rate, 446 2.3 Cardiac output (CO), 447 2.4 Measurement of cardiac output (CO), 450 2.5 Blood flow peripherally, 451 2.6 The cardiac cycle, 454 2.7 ECG, 458 2.8 Pharmacological manipulation of the heart and peripheral circulation, ...

Hemodynamics in awake rabbits during hyperbaric helium-oxygen exposure

1980 ◽  
Vol 48 (2) ◽  
pp. 281-283 ◽  
Author(s):  
L. E. Boerboom ◽  
J. N. Boelkins
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Cardiovascular System ◽  
Systemic Vascular Resistance ◽  
Elevated Pressure ◽  
Inert Gases ◽  
Gas Mixture ◽  
Organ Blood Flow

Although man is being exposed to hyperbaric environments more frequently, the effects of these environments and the inert gases used are not clearly defined. We therefore designed an experiment to examine both the effects of helium and elevated pressure on the cardiovascular system in conscious rabbits exposed to normoxic levels of a helium-oxygen (He-O2) gas mixture at 1 and 11 atmospheres absolute (ATA) for 2 h. Variables studied included heart rate, blood pressure, cardiac output, systemic vascular resistance, organ blood flow, and resistance to flow. The only change observed was a decrease in heart rate from a control of 284 +/- 7 (mean +/- SE) to 246 +/- 12 beats/min after 2 h of breathing He-O2 at 1 ATA. We therefore conclude that the cardiovascular system is not adversely affected by helium or elevated pressure as used in this experiment.

Cardiovascular system

2017 ◽  
Author(s):  
Mark Harrison
Keyword(s):  
Blood Pressure ◽  
Emergency Medicine ◽  
Cardiovascular System ◽  
Body Fluid ◽  
Cardiac Cycle ◽  
Colloidal Solutions ◽  
Pharmacological Manipulation ◽  
System P ◽  
Body Fluid Homeostasis ◽  
Crystalloid Solutions

This chapter describes the pathophysiology of the cardiovascular system as it applies to Emergency Medicine, and in particular the Primary FRCEM examination. The chapter outlines the key details of the control of blood pressure and heart rate, cardiac output, blood flow, cardiac cycle, ECG, pharmacological manipulation of the heart, shock, oxygen delivery and consumption, body fluid homeostasis, crystalloid solutions, colloidal solutions, and exudates and transudates. This chapter is laid out exactly following the RCEM syllabus, to allow easy reference and consolidation of learning.

Normal function of the cardiovascular system

2018 ◽  
Author(s):  
Manish Kalla ◽  
Neil Herring
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Cardiovascular System ◽  
Cardiac Cycle ◽  
Normal Function ◽  
Cardiac Physiology ◽  
Local Blood Flow ◽  
System P ◽  
Vascular Physiology ◽  
Flow Capillary

This chapter discusses normal function of the cardiovascular system, including cardiac physiology (the cardiac cycle, ECG, blood flow and heart sounds, control of cardiac output), vascular physiology (control of local blood flow, capillary transfer), integrated cardiovascular control,

Differential effect of behavior on cardiac and vasomotor baroreflex responses

1986 ◽  
Vol 251 (1) ◽  
pp. R126-R136 ◽  
Author(s):  
C. A. Combs ◽  
O. A. Smith ◽  
C. A. Astley ◽  
E. O. Feigl
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Peripheral Circulation ◽  
Baroreceptor Reflex ◽  
Aortic Blood Flow ◽  
Renal Vasoconstriction ◽  
Bilateral Carotid Occlusion ◽  
Bilateral Carotid ◽  
Carotid Sinus Baroreflex

Bilateral carotid occlusion was performed in seven baboons during dynamic leg exercise, static arm exercise, feeding, rest, and sleep. The baroreceptor reflex effects on blood pressure, heart rate and interval, renal blood flow, and terminal aortic blood flow were determined during each behavior. The carotid sinus baroreflex increase in blood pressure and heart rate was greatest during sleep and least during exercise. The hindlimb and renal vasomotor responses followed different patterns. The baroreceptor reflex sensitivity for renal vasoconstriction was greatest during rest and least during sleep. The reflex sensitivity in the hindlimb was unaltered by behavior. Thus behavior modifies baroreceptor reflex responses in the heart and peripheral circulation in different patterns.

scholarly journals The ocular cardiac reflex effect study on cardiac hemodynamic parameters in healthy young mans.

2019 ◽  
Vol 40 (1) ◽  
pp. 17-24
Author(s):  
A. I. Palamarchuk
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiovascular System ◽  
Peripheral Resistance ◽  
Blood Flow Rate ◽  
Effect Study ◽  
Nonlinear Dependence ◽  
System Response ◽  
Hemodynamic Parameters

Purpose of the study. Investigate changes of cardiac hemodynamic parameters caused by ocular cardiac reflex triggering in healthy men’s in youthful age.Material and methods. 120 healthy male volunteers in youthful age were examined. The mean age was (19,2 ± 0,93 years). For ocular-cardiac reflex (OCR) triggering we used a patented model «Device for dosed compression effects on the eyeballs» and «The method of ocular cardiac reflex triggering». On the basis of the obtained parameters of systolic (SBP) and diastolic (DBP) blood pressure, by arithmetic operations, pulse pressure (PP) and average flow pressure (AFP) and integrative parameters of cardiohemodynamics (CHD) – systolic blood volume (SBV), minute blood flow volume (MBFV), volumetric blood flow rate (V), total peripheral resistance (TPR) were determined. Results. Three main types of cardiovascular system response on OCR triggering were identified. The first type – hypertensive (n = 30 (25%) of the total number of examined subjects) was characterized by a significant (p < 0,05) increase in heart rate, SBP, DBP, PP, AFP and other integrative parameters of CHD. The second, hypotonic type of the response (62 subjects; 51,7%) was characterized by a significant (p < 0,05) decrease in SBP, DBP, PP, AFP. Patients with third, dystonic type, of response (n = 28 (23,3%) of the total number examined subjects) showed significant bilateral changes of blood pressure parameters in a nonlinear dependence of compression power on the eyeballs. Determination CHD parameters directly after and 3 and 5 minutes after decompression of the air in the compression device we enabled to determine the subtype of the mobility of the nervous centers as a feature that complements the basic type. The subtype of normal mobility was revealed in 63,3% (n = 19) of subjects with the main hypertensive type of response, 69,3% (n = 43) of subjects with the main hypotonic and 60,7 % (n = 17) with the main dystonic type of response of the cardiovascular system. The inert subtype in the mobility of the cardiovascular system were identified in 36,7% (n = 11) individuals with hypertension is the main type of response, at 30,7% (n = 19) of individuals with primary hypotonic type of response and 39,3 % (n = 11) – distancing. The obtained typological changes in blood pressure parameters caused by OCR triggering allowed to reveal predisposition to hypertension, hypotension, dystonia and to predict the development of hypertension in patients with hypertensive type of response usin appropriate primary prevention changes in life style. The highest risk of hypertension development may be in persons with hypertensive inert type of reaction of the system of regulation of blood pressure on OCR triggering. Further studies are being conducted to confirm this assumption. Keywords: oculo-cardiac reflex, blood pressure, heart rate, young age.

scholarly journals Effects of meal ingestion on blood pressure and regional hemodynamic responses after exercise

2016 ◽  
Vol 120 (11) ◽  
pp. 1343-1348 ◽  
Author(s):  
Masako Yamaoka Endo ◽  
Chizuko Fujihara ◽  
Akira Miura ◽  
Hideaki Kashima ◽  
Yoshiyuki Fukuba
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Young Male ◽  
Random Order ◽  
Carbohydrate Ingestion ◽  
Liquid Meal ◽  
Severe Hypotension ◽  
Meal Ingestion

This study investigated the combined effects of consuming a meal during postexercise hypotension (PEH) on hemodynamics. Nine healthy young male subjects performed each of three trials in random order: 1) cycling at 50% of heart rate reserve for 60 min, 2) oral ingestion of a carbohydrate liquid meal (75 g glucose), or 3) carbohydrate ingestion at 40 min after cycling exercise. Blood pressure, heart rate, cardiac output, and blood flow in the superior mesenteric (SMA), brachial, and popliteal arteries were measured continuously before and after each trial. Regional vascular conductance (VC) was calculated as blood flow/mean arterial pressure. Blood pressure decreased relative to baseline values ( P < 0.05) after exercise cessation. Blood flow and VC in the calf and arm increased after exercise, whereas blood flow and VC in the SMA did not. Blood pressure did not change after meal ingestion; however, blood flow and VC significantly decreased in the brachial and popliteal arteries and increased in the SMA for 120 min after the meal ( P < 0.05). When the meal was ingested during PEH, blood pressure decreased below PEH levels and remained decreased for 40 min before returning to postexercise levels. The sustained increase in blood flow and VC in the limbs after exercise was reduced to baseline resting levels immediately after the meal, postprandial cardiac output was unchanged by the increased blood flow in the SMA, and total VC and SMA VC increased. Healthy young subjects can suppress severe hypotension by vasoconstriction of the limbs even when carbohydrate is ingested during PEH.

Effect of excitement on coronary and systemic energetics in unanesthetized dogs

1965 ◽  
Vol 209 (4) ◽  
pp. 680-688 ◽  
Author(s):  
Claudia R. Rayford ◽  
Edward M. Khouri ◽  
Donald E. Gregg
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Coronary Flow ◽  
Cardiac Cycle ◽  
Myocardial Metabolism ◽  
Aortic Pressure ◽  
Moderate Increase ◽  
Sizeable Increase

The effect of excitement on phasic aortic pressure and flow, phasic left coronary flow, and myocardial metabolism has been studied in dogs 1–8 weeks after implantation of appropriate flowmeters and other devices. The rapid increase in heart rate and mild increase in blood pressure in the first few seconds tend to maintain coronary flow per minute despite a decrease in stroke cardiac output and coronary flow throughout the cardiac cycle. The main response is a delayed rise in coronary flow per minute resulting from further elevation of heart rate and blood pressure, a moderate increase in stroke cardiac output and a sizeable increase in stroke coronary flow, the latter being divided fairly evenly between systole and diastole. From 60 to 90% of the increase in mean coronary flow arises from the increase in stroke coronary flow, and the remainder from the increased number of heartbeats per minute. Some of the possible mechanisms concerned are discussed.

Effects of peptide YY on the human cardiovascular system: reversal of responses to vasoactive intestinal peptide

1992 ◽  
Vol 263 (4) ◽  
pp. E740-E747 ◽  
Author(s):  
R. J. Playford ◽  
M. A. Benito-Orfila ◽  
P. Nihoyannopoulos ◽  
K. A. Nandha ◽  
J. Cockcroft ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Cardiovascular System ◽  
Vasoactive Intestinal Peptide ◽  
Brachial Artery ◽  
Peptide Yy ◽  
Intestinal Secretion ◽  
Venous Occlusion ◽  
Human Cardiovascular System

Peptide YY (PYY) reverses the increased intestinal secretion stimulated by vasoactive intestinal peptide (VIP) in humans. VIP also dilates blood vessels, so we investigated the effect of PYY on the cardiovascular system. Six volunteers received PYY, 0.4 and 1.2 pmol.kg-1 x min-1 i.v. for 2 h, reproducing plasma levels seen postprandially and during a diarrheal illness, respectively. Cardiac function was assessed by echocardiography. PYY infused at 0.4 pmol.kg-1 x min-1 had no effect on cardiovascular parameters. PYY infused at 1.2 pmol.kg-1 x min-1 caused a fall in both stroke volume from 128 +/- 8 to 110 +/- 8 ml/beat (mean +/- 95 confidence interval, P < 0.01) and cardiac output from 7.2 +/- 0.4 to 6.1 +/- 0.4 l/min (P < 0.01). Effects of infusion of PYY into the brachial artery at doses of 0-16 pmol/min were assessed using venous occlusion plethysmography in six subjects. PYY infusion caused a dose-dependent fall in forearm blood flow. Six subjects received VIP, 5 pmol.kg-1 x min-1 i.v., causing a rise in heart rate from 55 +/- 3 to 70 +/- 3 beats/min and increased cardiac output from 7.3 +/- 1.1 to 13.1 +/- 1.1 l/min. The addition of PYY, 0.4 pmol.kg-1 x min-1 i.v., did not affect the heart rate significantly but decreased the cardiac output to 10.4 +/- 1.1 l/min (P < 0.01). Infusions of PYY into the brachial artery at 5 pmol/min decreased local vasodilation induced by VIP infused at 2 pmol/min at the same site by 40% (P < 0.01), even though this dose of PYY had no significant effect on local blood flow when given alone.(ABSTRACT TRUNCATED AT 250 WORDS)

The Haemodynamic Effects of Metabolic Acidosis in the Rat

1976 ◽  
Vol 50 (3) ◽  
pp. 177-184 ◽  
Author(s):  
J. Yudkin ◽  
R. D. Cohen ◽  
Barbara Slack
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Metabolic Acidosis ◽  
Renal Blood Flow ◽  
Hepatic Blood Flow ◽  
Conscious Rats ◽  
Blood Ph ◽  
Significant Difference

1. The effect of metabolic acidosis of 4–6 h duration on cardiac output, blood pressure, heart rate, and hepatic and renal blood flow has been studied in the rat. 2. In anaesthetized rats, blood pressure and heart rate fell linearly with blood pH in both sham-operated and nephrectomized rats. There was no significant difference between the two groups in the effect of acidosis on either variable. 3. Cardiac output showed a significant fall with increasing acidosis in the conscious rat. 4. Estimated hepatic blood flow in conscious rats showed a significant positive correlation with blood pH in both sham-operated and nephrectomized animals. There was no significant difference in estimated hepatic blood flow between the two groups of animals at any blood pH. 5. In conscious rats, increasing acidosis caused a progressive decrease in estimated renal blood flow. 6. It is concluded that the increase in the previously described apparent renal contribution to lactate removal in the acidotic rat cannot be explained by any circulatory effect mediated by the kidney. The possible relevance of the findings to lactate homeostasis is discussed.

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