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Organ Systems Physiological Changes: Cardiovascular

Figure 2: Figure Legend

Figure 2 shows the basic anatomy of the human heart and its conduction system. Here is a more detailed version of the caption that accompanies that image: Panel A shows the front view of the heart cut vertically. Panel B shows a front view of the heart cut horizontally. Panel C is a front view of the heart cut vertically to show how the signal to begin a heart beat is initiated in the sinoatrial node and conducted to the rest Figure 5 Maximal oxygen uptake (VO2max) declines in linear fashion for both trained and untrained individuals. Lines for individuals that engage in regular exercise and inactive persons are based on norms established from cross-sectional data of Heath et al. Longitudinal data from individuals studied over a twenty-year span confirm both the linearity and slope (Pollack et al.). Individuals may move vertically within the gray area by increasing or decreasing their levels of regular exercise training (Schulman et al., Trappe et al., Pollack et al.). Longitudinal studies suggest the upper line (individuals who exercise regularly) may be parallel, less steep, or more steep in men, while the most compelling data suggests that the upper line declines at a steeper rate for women (Tanaka et al., Fitzgerald et al.). SOURCE: Numerous journal articles were used to create this figure. Please consult the bibliography for this essay to locate all of the articles cited in the caption above. of the heart by the atrioventricular node and bundle, the bundle branches, and the purkinje fibers. Panel D is an electrocardiogram showing how electrical events in the cardiac conduction system relate to P, QRS, and T waves.



FITZGERALD, M. D.; TANAKA, H.; TRAN, Z. V.; and SEALS, D. R. "Age-Related Declines in Maximal Aerobic Capacity in Regularly Exercising vs. Sedentary Women: A Meta-Analysis." Journal of Applied Physiology 83, no. 1 (1997): 160–165.

FLEG, J. L.; O'CONNOR, F. C.; GERSTENBLITH, G.; BECKER, L. C.; CLULOW, J.; SCHULMAN, S. P.; and LAKATTA, E. G. "Impact of Age on the Cardiovascular Response to Dynamic Upright Exercise in Healthy Men and Women." Journal of Applied Physiology 78 (1995): 890–900.

HEATH, G. W.; HAGBERG, J. M.; EHSANI, A. A.; and HOLLOSZY, J. O. "A Physiological Comparison of Young and Older Endurance Athletes." Journal Applied Physiology 51 (1981): 634–640.

KANNEL, W. B., and BELANGER, A. J. "Epidemiology of Heart Failure." American Heart Journal 121 (1991): 951–957.

LAKATTA, E. G. "Cardiovascular Regulatory Mechanisms in Advanced Age." Physiological Reviews 73 (1993): 413–467.

POLLOCK, M. L.; MENGELKOCH, L. J.; GRAVES, J. E.; LOWENTHAL, D. T.; LIMACHER, M. C.; FOSTER, C.; and WILMORE, J. H. "Twenty-year Follow-Up of Aerobic Power and Body Composition of Older Track Athletes." Journal Applied Physiology 82 (1997):1508–1516.

SCHULMAN, S. P. et al. "Continuum of Cardiovascular Performance Across a Broad Range of Fitness Levels in Healthy Older Men." Circulation Research 94 (1996): 359–367.

TANAKA, H.; DESOUZA, C. A.; JONES, P. P.; STEVENSON, E. T.; DAVY, K. P.; and SEALS, D. R. "Greater Rate of Decline in Maximal Aerobic Capacity with Age in Physically Active vs. Sedentary Healthy Women." Journal of Applied Physiology 83 (1997): 1947–1953.

TRAPPE, S. W.; COSTILL, D. L.; VUKOWICH, M. D.; JONES, J.; and MALHAM, T. "Aging Among Elite Distance Runners: A 22-Year Longitudinal Study." Journal of Applied Physiology 80 (1996): 285–290.

WHITE, M.; RODEN, R.; MINOBE, W.; KHAN, M. F.; LARRABEE, P.; WOLLMERING, M.; PORT, J. D.; ANDERSON, F.; CAMPBELL, D.; and FELDMAN, A. M. "Age-related Changes in β-Adrenergic Neuroeffector Systems in the Human Heart." Circulation 90 (1994): 1225–1238.

Additional topics

Medicine EncyclopediaAging Healthy - Part 3Organ Systems Physiological Changes: Cardiovascular - Heart Structure And Function At Rest, Reserve Capacity Of The Heart, Vascular Structure And Function At Rest