Haemolymph flow distribution, cardiac performance and ventilation during moderate walking activity in Cancer magister (Dana) (Decapoda, Crustacea)

1996 ◽  
Vol 199 (3) ◽  
pp. 627-633 ◽  
Author(s):  
B Wachter ◽  
B Mcmahon
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Relative Proportion ◽  
Flow Distribution ◽  
Ventilation Rate ◽  
Arterial System ◽  
Cancer Magister ◽  
Walking Activity ◽  
Flow Through

Adult male Cancer magister (Dana) were equipped with pulsed-Doppler flowmeters and pressure transducers for simultaneous measurement of heart and ventilation frequencies, haemolymph flow through each of the major arterial systems and cardiac output and for calculation of stroke volume. Each variable was measured at rest and during two consecutive periods of moderate treadmill walking activity and recovery. During activity, haemolymph flow through the sternal and anterolateral arteries increased, while flow through the hepatic arterial system decreased. This resulted in a redistribution of haemolymph flow in which a proportion of cardiac output was shifted from the anterior, posterior and hepatic arterial systems to the sternal arterial system. The relative proportion of the cardiac output flowing through the anterolateral artery remained constant. This indicated that oxygen supply was shifted away from the digestive system to the muscles of the walking legs and the respiratory system. Cardiac output, heart rate and stroke volume all increased in response to activity. The increase in cardiac output is the result of a large increase in stroke volume and a small increase in heart rate. A doubling of ventilation rate also occurred during activity. Both the circulatory and ventilatory systems were restored to pre-activity values by 60 min of recovery.

Cardiovascular changes associated with thermal polypnea in the chicken

1964 ◽  
Vol 207 (6) ◽  
pp. 1349-1353 ◽  
Author(s):  
G. C. Whittow ◽  
P. D. Sturkie ◽  
G. Stein
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Respiratory Rate ◽  
Peripheral Resistance ◽  
Flow Through ◽  
Skin Temperatures ◽  
Increased Blood Flow

The effect of hyperthermia on the respiratory rate, cardiac output, blood pressure, arterial hematocrit, and the skin temperatures of the extremities of unanesthetized hens has been investigated. During hyperthermia, the respiratory rate increased to a maximal value and then declined. There was also an increase in cardiac output, followed by a decrease, but the peak cardiac output occurred at a rectal temperature which was significantly higher than that at which the peak respiratory rate was recorded. The increase in cardiac output was the result of an increase in both stroke volume and heart rate. The diminution of cardiac output seemed to be related to a decrease in the stroke volume at high levels of heart rate. The decrease in blood pressure and total peripheral resistance was attributed partly to an increased blood flow through the extremities.

Visceral blood flow distribution during exercise to exhaustion in conscious dogs

1976 ◽  
Vol 40 (6) ◽  
pp. 927-931 ◽  
Author(s):  
T. M. Sanders ◽  
R. A. Werner ◽  
C. M. Bloor
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Flow Distribution ◽  
Aortic Pressure ◽  
Organ Blood Flow ◽  
Hemodynamic Parameters ◽  
Blood Flow Distribution ◽  
Mean Aortic Pressure

We measured changes in organ blood flow (OBF) distribution and systemic hemodynamics in 9 dogs running 5–13 km/h during steady-state (SS) and exhaustive (EE) exercise on a treadmill at 8–15% grade for an average of 35 min. SS was defined when a heart rate (HR) of 80% maximum was attained and when HR was constant for 5–8 min. EE was defined as when the dog collapsed, unable to run longer. We measured heart rate, mean aortic pressure, cardiac output, and stroke volume via implanted probes and catheters. All hemodynamic parameters rose significantly (P less than 0.05) with exercise. Stroke volume and aortic pressure did not rise above SS levels during EE. OBF, determined with microspheres, to the liver, stomach, and intestines declined during SS and returned to control levels during EE. OBF to the kidneys and pancreas was not significantly changed by either SS or EE. OBF to the spleen declined progressively with SS and EE. We concluded that 1) the effect of exercise on OBF depends on the severity of exercise, emphasizing the need to quantify work loads in exercise studies, and 2) the splanchnic organs do not respond homogeneously to exercise and that this response is not adequately described by % of CO assessments.

Physiological factors associated with the lower maximal oxygen consumption of master runners

1989 ◽  
Vol 66 (2) ◽  
pp. 949-954 ◽  
Author(s):  
A. M. Rivera ◽  
A. E. Pels ◽  
S. P. Sady ◽  
M. A. Sady ◽  
E. M. Cullinane ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Maximal Oxygen Consumption ◽  
Maximal Heart Rate ◽  
Distance Runners ◽  
Physiological Factors ◽  
Factors Associated ◽  
Older Athletes ◽  
Maximal Cardiac Output

We examined the hemodynamic factors associated with the lower maximal O2 consumption (VO2max) in older formerly elite distance runners. Heart rate and VO2 were measured during submaximal and maximal treadmill exercise in 11 master [66 +/- 8 (SD) yr] and 11 young (32 +/- 5 yr) male runners. Cardiac output was determined using acetylene rebreathing at 30, 50, 70, and 85% VO2max. Maximal cardiac output was estimated using submaximal stroke volume and maximal heart rate. VO2max was 36% lower in master runners (45.0 +/- 6.9 vs. 70.4 +/- 8.0 ml.kg-1.min-1, P less than or equal to 0.05), because of both a lower maximal cardiac output (18.2 +/- 3.5 vs. 25.4 +/- 1.7 l.min-1) and arteriovenous O2 difference (16.6 +/- 1.6 vs. 18.7 +/- 1.4 ml O2.100 ml blood-1, P less than or equal to 0.05). Reduced maximal heart rate (154.4 +/- 17.4 vs. 185 +/- 5.8 beats.min-1) and stroke volume (117.1 +/- 16.1 vs. 137.2 +/- 8.7 ml.beat-1) contributed to the lower cardiac output in the older athletes (P less than or equal 0.05). These data indicate that VO2max is lower in master runners because of a diminished capacity to deliver and extract O2 during exercise.

Physiological variability in neonatal armadillo quadruplets: within- and between-litter differences

2000 ◽  
Vol 203 (11) ◽  
pp. 1733-1740 ◽  
Author(s):  
B. Bagatto ◽  
D.A. Crossley ◽  
W.W. Burggren
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Ventilation Rate ◽  
Dasypus Novemcinctus ◽  
Genetic Components ◽  
Physiological Variability ◽  
In Captivity ◽  
Flow Through ◽  
Physiological Characters

The role of genetics on neonatal physiological variability was examined in the nine-banded armadillo (Dasypus novemcinctus). Since armadillos give birth to only monozygous quadruplets, the genetic variation within litters is essentially zero. Quadruplets born in captivity were isolated and weighed within 8 h of birth. Oxygen consumption (V.(O2)) was measured in resting neonates by flow-through respirometry, heart rate obtained from an electrocardiogram and ventilation was measured by impedance techniques. Following the measurements, neonates were returned to the mother. Measurements were repeated at 4 and 8 days after birth. Mean heart rate significantly increased from 132 beats min(−1) on the day of birth to 169 beats min(−1) on day 8. Mean ventilation rate significantly decreased from 81 breaths min(−1) on the day of birth to 54 breaths min(−1) on day 8. During this same developmental period, mean mass significantly increased from 100 g to 129 g, and mean mass-specific oxygen consumption significantly decreased from 32.2 ml O(2)kg(−1)min(−1) to 28.6 ml O(2)kg(−1) min(−1). For all variables measured, within-litter variability was always significantly less than between-litter variability, confirming a ‘sibling effect’ that we attribute to the genetic components determining physiological characters.

Short-term emersion affects cardiac function and regional haemolymph distribution in the crab Cancer magister

1996 ◽  
Vol 199 (3) ◽  
pp. 569-578
Author(s):  
C Airriess ◽  
B Mcmahon
Keyword(s):  
Stroke Volume ◽  
Cardiac Function ◽  
Large Scale ◽  
Time Course ◽  
Beat Frequency ◽  
Heart Beat ◽  
Experimental Chamber ◽  
Cancer Magister ◽  
Flow Through ◽  
Cardiac Stroke Volume

Changes in cardiac function and arterial haemolymph flow associated with 6 h of emersion were investigated in the crab Cancer magister using an ultrasonic flowmeter. This species is usually found sublittorally but, owing to the large-scale horizontal water movements associated with extreme tides, C. magister may occasionally become stranded on the beach. Laboratory experiments were designed such that the emersion period was typical of those that might be experienced by this crab in its natural environment. The frequency of the heart beat began to decline sharply almost immediately after the start of the experimental emersion period. Cardiac stroke volume fell more gradually. The combined reduction in these two variables led to a maximum decrease in cardiac output of more than 70 % from the control rate. Haemolymph flow through all the arteries originating at the heart, with the exception of the anterior aorta, also declined markedly during emersion. As the water level in the experimental chamber fell below the inhalant branchial openings, a stereotypical, dramatic increase in haemolymph flow through the anterior aorta began and this continued for the duration of the emersion period. The rapid time course of the decline in heart-beat frequency and the increase in haemolymph flow through the anterior aorta suggest a neural mechanism responding to the absence of ventilatory water in the branchial chambers. These responses may be adaptations, respectively, to conserve energy by reducing the minute volume of haemolymph pumped by the heart and to protect the supply of haemolymph to cephalic elements of the central nervous system. The decline in cardiac stroke volume, which occurs more slowly over the emersion period, may be a passive result of the failure to supply sufficient O2 to meet the aerobic demands of the cardiac ganglion.

CARDIOVASCULAR ADAPTATIONS ENHANCE TOLERANCE OF ENVIRONMENTAL HYPOXIA IN THE CRAB CANCER MAGISTER

1994 ◽  
Vol 190 (1) ◽  
pp. 23-41 ◽  
Author(s):  
C Airriess ◽  
B Mcmahon
Keyword(s):  
Cardiac Output ◽  
Beat Frequency ◽  
Direct Calculation ◽  
Exposure Period ◽  
Heart Beat ◽  
High Rate ◽  
Hypoxic Exposure ◽  
Cancer Magister ◽  
Control Value ◽  
Flow Through

Unrestrained crabs instrumented with probes for ultrasonic measurement of arterial haemolymph flow were subjected to 6 h of hypoxic exposure. During this interval, the inhalant O2 partial pressure was reduced in steps from 18 to 3 kPa. Measurement of haemolymph flow through all arteries leaving the heart allowed direct calculation of cardiac output, stroke volume and the distribution of cardiac output for both non-stressed and hypoxic animals. Resting levels of cardiac output were low compared with previously reported values for this and other species of decapod crustaceans. During exposure to the most severe level of hypoxia tested, haemolymph flow through the anterior arteries decreased while flow through the posterior aorta and sternal artery increased by 55 % and 27 % respectively. Cardiac output increased from a control value of 9.8±1.6 to 11.9±1.2 ml kg-1 min-1 despite a decrease in heart-beat frequency. Scaphognathite beat frequency increased from 82.1±4.3 min-1 to more than 120 min-1 after 90 min of hypoxic exposure and remained at this level for the duration of the exposure period. The decrease in haemolymph flow, via the anterior arteries, to the antero-dorsal region of the animal concurrent with an increase in flow to the posterior and antero-ventral regions, via the posterior aorta and sternal artery, implicates an active mechanism for redistribution of haemolymph flow during hypoxic exposure. The high rate of scaphognathite pumping, presumably to maximise O2 uptake during experimental hypoxia, was probably made possible by an increased blood supply to these organs, which are perfused by downstream branches of the sternal artery.

Cardiovascular changes in the exercising emu

1983 ◽  
Vol 104 (1) ◽  
pp. 193-201 ◽  
Author(s):  
B. Grubb ◽  
D. D. Jorgensen ◽  
M. Conner
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Oxygen Content ◽  
Body Mass ◽  
Fold Increase ◽  
Exercise Heart Rate ◽  
Rate Of Oxygen Consumption ◽  
Cardiovascular Variables

Cardiovascular variables were studied as a function of oxygen consumption in the emu, a large, flightless ratite bird well suited to treadmill exercise. At the highest level of exercise, the birds' rate of oxygen consumption (VO2) was approximately 11.4 times the resting level (4.2 ml kg-1 min-1). Cardiac output was linearly related to VO2, increasing 9.5 ml for each 1 ml increase in oxygen consumption. The increase in cardiac output is similar to that in other birds, but appears to be larger than in mammals. The venous oxygen content dropped during exercise, thus increasing the arteriovenous oxygen content difference. At the highest levels of exercise, heart rate showed a 3.9-fold increase over the resting rate (45.8 beats min-1). The mean resting specific stroke volume was 1.5 ml per kg body mass, which is larger than shown by most mammals. However, birds have larger hearts relative to body mass than do mammals, and stroke volume expressed per gram of heart (0.18 ml g-1) is similar to that for mammals. Stroke volume showed a 1.8-fold increase as a result of exercise in the emus, but a change in heart rate plays a greater role in increasing cardiac output during exercise.

Cardiac Response During Trumpet Playing

2010 ◽  
Vol 25 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Donald U Robertson ◽  
Lynda Federoff ◽  
Keith E Eisensmith
Keyword(s):  
College Students ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Cardiac Response ◽  
Physiological Efficiency ◽  
Rest Periods ◽  
Upper Register

Heart rate, heart rate variability, stroke volume, and cardiac output were measured while six college students and six professionals played trumpet. One-minute rest periods were followed by 1 minute of playing exercises designed to assess the effects of pitch and articulation. Heart rate and heart rate variability increased during playing, but stroke volume decreased. Changes in heart rate between resting and playing were greater for students, although beat-to-beat variability was larger for professionals in the upper register. These results suggest that expertise is characterized by greater physiological efficiency.

In the Loop—Left Ventricular Pressures

2011 ◽  
pp. 42-47
Author(s):  
James R. Munis
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Aortic Valve ◽  
Left Ventricle ◽  
Stroke Volume ◽  
Cardiovascular System ◽  
Aortic Root ◽  
Left Ventricular ◽  
Root Pressure ◽  
The Third

We've already looked at 2 types of pressure that affect physiology (atmospheric and hydrostatic pressure). Now let's consider the third: vascular pressures that result from mechanical events in the cardiovascular system. As you already know, cardiac output can be defined as the product of heart rate times stroke volume. Heart rate is self-explanatory. Stroke volume is determined by 3 factors—preload, afterload, and inotropy—and these determinants are in turn dependent on how the left ventricle handles pressure. In a pressure-volume loop, ‘afterload’ is represented by the pressure at the end of isovolumic contraction—just when the aortic valve opens (because the ventricular pressure is now higher than aortic root pressure). These loops not only are straightforward but are easier to construct just by thinking them through, rather than by memorization.

Hemodynamic Changes During Discontinuation of Mechanical Ventilation in Medical Intensive Care Unit Patients

2006 ◽  
Vol 15 (6) ◽  
pp. 580-593 ◽  
Author(s):  
Susan K. Frazier ◽  
Kathleen S. Stone ◽  
Debra Moser ◽  
Rebecca Schlanger ◽  
Carolyn Carle ◽  
...  
Keyword(s):  
Heart Rate ◽  
Mechanical Ventilation ◽  
Cardiac Output ◽  
Continuous Positive Airway Pressure ◽  
Stroke Volume ◽  
Cardiac Dysfunction ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Plasma Catecholamine ◽  
Medical Intensive Care

• Background Cardiac dysfunction can prevent successful discontinuation of mechanical ventilation. Critically ill patients may have undetected cardiac disease, and cardiac dysfunction can be produced or exacerbated by underlying pathophysiology. • Objective To describe and compare hemodynamic function and cardiac rhythm during baseline mechanical ventilation with function and rhythm during a trial of continuous positive airway pressure in medical intensive care patients. • Methods A convenience sample of 43 patients (53% men; mean age 51.1 years) who required mechanical ventilation were recruited for this pilot study. Cardiac output, stroke volume, arterial blood pressure, heart rate, cardiac rhythm, and plasma catecholamine levels were measured during mechanical ventilation and during a trial of continuous positive airway pressure. • Results One third of the patients had difficulty discontinuing mechanical ventilation. Successful patients had significantly increased cardiac output and stroke volume without changes in heart rate or arterial pressure during the trial of continuous positive airway pressure. Unsuccessful patients had no significant changes in cardiac output, stroke volume, or heart rate but had a significant increase in mean arterial pressure. The 2 groups of patients also had different patterns in ectopy. Concurrently, catecholamine concentrations decreased in the successful patients and significantly increased in the unsuccessful patients during the trial. • Conclusions Patterns of cardiac function and plasma catecholamine levels differed between patients who did or did not achieve spontaneous ventilation with a trial of continuous positive airway pressure. Cardiac function must be systematically considered before and during the return to spontaneous ventilation to optimize the likelihood of success.

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