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Keywords: stroke volume
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Journal Articles
J Exp Biol (2020) 223 (4): jeb215335.
Published: 20 February 2020
... at factors beyond the heart, namely vascular capacitance and conductance. Capacitance Vasculature Cardiac output Mean circulatory filling pressure Reptile Fish Resistance Exercise Stroke volume Contractility Inotropy Vasodilatation Arthur C. Guyton (1919–2003) revolutionised...
Journal Articles
J Exp Biol (2019) 222 (18): jeb206714.
Published: 16 September 2019
... flow magnetic resonance imaging (MRI) – to validate stroke volume measurements and end diastolic ventricular blood volume. This produced an estimate of ejection fraction in our study species, the red footed tortoise Chelonoidis carbonarius ( n =5), under isoflurane anaesthesia of 88±11%. After...
Includes: Supplementary data
Journal Articles
J Exp Biol (2019) 222 (6): jeb199828.
Published: 21 March 2019
... of the red-eared slider turtle ( Trachemys scripta elegans ), we demonstrated that activation of smooth muscle contraction with histamine (100 nmol kg −1 bolus injected into perfusate) reduced cardiac output by decreasing stroke volume (>50% decrease in both parameters). Conversely, inhibition of...
Includes: Supplementary data
Journal Articles
J Exp Biol (2019) 222 (5): jeb198457.
Published: 07 March 2019
... internal organs, and the stroke volume and cardiac output during the surface state. We then simulated breath-holding conditions and perfusion of the internal organs under the diving-induced bradycardia and reduction of stroke volume and cardiac output, using 10 beats min −1 as the limit for the heart rate...
Journal Articles
J Exp Biol (2018) 221 (15): jeb183160.
Published: 13 August 2018
... activity, and show the same cardiac breakpoint temperature as the red-blooded Antarctic fish Notothenia coriiceps . Cardiac output Heart rate Stroke volume ECG Warming Sympathovagal balance The notothenioid suborder of fishes that are dominant in the frigid Southern Ocean include the...
Includes: Supplementary data
Journal Articles
J Exp Biol (2018) 221 (1): jeb162693.
Published: 09 January 2018
... extinct pterodactyls. Given that powered flight represents a demanding aerobic activity, an efficient cardiovascular system is essential for the continuous delivery of oxygen to the pectoral muscles during flight. It is well known that the limiting step in the circulation is stroke volume (the volume of...
Journal Articles
J Exp Biol (2017) 220 (3): 336–340.
Published: 01 February 2017
...William Joyce; Michael Axelsson; Tobias Wang ABSTRACT Most vertebrates increase cardiac output during activity by elevating heart rate with relatively stable stroke volume. However, several studies have demonstrated ‘intrinsic autoregulation’ of cardiac output where artificially increased heart...
Journal Articles
J Exp Biol (2016) 219 (13): 1974–1984.
Published: 01 July 2016
..., the blood-oxygen carrying capacity was higher than that of barnacle geese. Resting cardiac output also did not differ between groups and increased at least twofold during progressive hypoxia, initially as a result of increases in stroke volume. However, cardiac output increased at a higher F i O 2...
Includes: Supplementary data
Journal Articles
J Exp Biol (2016) 219 (3): 457–463.
Published: 01 February 2016
... pressures to calculate left ventricular wall stress. Cardiac output was also determined by inert gas rebreathing to provide an additional and independent estimate of stroke volume. Echocardiography and inert gas-rebreathing yielded similar cardiac outputs of 16.1±2.5 and 16.4±1.4 l min −1 , respectively...
Includes: Supplementary data
Journal Articles
J Exp Biol (2014) 217 (6): 964–973.
Published: 15 March 2014
... adjacent vessels were measured by magnetic resonance imaging. In synthetic seawater at 23°C (immersed condition), the end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV) were 50%, 21% and 29% of the heart volume, respectively, and the auricle volume ( V A ) was maximized at end...
Includes: Supplementary data
Journal Articles
J Exp Biol (2010) 213 (21): 3710–3716.
Published: 01 November 2010
... differences in basic lymph heart functions. The end diastolic volumes of posterior lymph hearts averaged 10.8 μl kg –1 in R. marina and 7.9–10.8 μl kg –1 in L. catesbeianus by conductance manometry, and 9–32 μl kg –1 in R. marina by ultasound techniques, which correlated with body mass. Stroke volumes were...
Includes: Multimedia, Supplementary data
Journal Articles
J Exp Biol (2010) 213 (21): 3636–3643.
Published: 01 November 2010
... (CgA 344-364 ) on the eel heart, as well as the eventual species-specific mechanisms of its myocardial action. Experiments were carried out on fresh-water eels ( Anguilla anguilla L.) using an electrically paced isolated working heart preparation. Stroke volume and stroke work were used as measures of...
Journal Articles
J Exp Biol (2009) 212 (18): 2941–2948.
Published: 15 September 2009
... geese is indicative of the relationship throughout the remainder of the annual cycle. * Author for correspondence( S.Portugal.1@bham.ac.uk ) 25 6 2009 2009 heart rate cardiovascular barnacle goose rate of oxygen consumption stroke volume Efficient use of energy is a...
Journal Articles
J Exp Biol (2007) 210 (10): 1715–1725.
Published: 15 May 2007
... pressure of oxygen in venous blood, P v O 2 ) and,secondarily, because the fish heart has an unusual ability to produce large increases in cardiac stroke volume ( V SH ) that allow cardiac output to be maintained during hypoxic bradycardia. Among the putative benefits of hypoxic bradycardia is an increase...
Journal Articles
J Exp Biol (2006) 209 (20): 4167–4173.
Published: 15 October 2006
... to air-breathe. An elevation of heart rate decreases cardiac filling time and therefore may cause a decline in stroke volume ( V S ), but this can be compensated for by an increase in venous tone to maintain stroke volume. Thus, the study on S. marmoratus was undertaken to investigate how stroke...
Journal Articles
J Exp Biol (2006) 209 (15): 2961–2970.
Published: 01 August 2006
..., Canada (e-mail: mgollock@uottawa.ca ) 9 5 2006 © The Company of Biologists Limited 2006 2006 Gadus morhua temperature cardiac output heart rate stroke volume metabolic rate haemoglobin blood oxygen concentration Temperature is an important environmental factor...
Journal Articles
J Exp Biol (2005) 208 (19): 3637–3643.
Published: 01 October 2005
... Imaging and phase contrast flow analysis to obtain accurate flow measurements from the base of the aorta. Heart rate ( f h )and cardiac output ( Q̇ ) were measured before, during and after dives in four restrained juvenile northern elephant seals, Mirounga angustirostris , and stroke volume( V s ) was...
Includes: Multimedia, Supplementary data
Journal Articles
J Exp Biol (2005) 208 (16): 3109–3120.
Published: 15 August 2005
... similarities and important differences. Although the avian allometric equations from this earlier study accurately predicted the flight Q̇ of our pigeons, this was primarily due to due to compensating discrepancies in their heart rate and stroke volume predictions. Additionally, the measured heart mass( M H...
Journal Articles
J Exp Biol (2005) 208 (10): 1927–1935.
Published: 15 May 2005
..., respectively), but not P da . In spite of an increased preload, the increase in Q̇ was exclusively mediated by an increased heart rate ( f h , from 80±4 beats min -1 to 88±4 and 103±3 beats min -1 ,respectively), and stroke volume ( V s ) remained unchanged. Prazosin treatment (1 mg kg -1 M b ) abolished...
Journal Articles
J Exp Biol (2002) 205 (6): 759–768.
Published: 15 March 2002
...J. A. W. Stecyk; A. P. Farrell SUMMARY In vivo measurements of the cardiovascular responses of anoxia-tolerant teleosts to severe prolonged hypoxia are limited. Here, we report the first direct measurements of cardiac output ( Q ), heart rate ( f H ) and stroke volume during prolonged severe...