chapter 8

7. Information originating in the brain that is transmitted to the cardiovascular, muscular, or pulmonary systems.
9. A heart rate that is maintained constant at submaximal levels of exercise when the rate of work is held constant.
10. The resistance to the flow of blood through the entire systemic circulation.
11. A breathing rate or tidal volume greater than necessary for normal function.
12. The degree to which the myocardium is stretched before it contracts, determined by factors such as central blood volume.
14. Labored or difficult breathing.
15. Older name for the ventilator breakpoint
18. hypoxemia A decline in arterial PO2 and arterial oxygen saturation during maximal or near-maximal exercise.
19. The pressure exerted by a stationary column of fluid in a tube.
20. The ratio of volume of air ventilated and the amount of oxygen consumed indicates breathing economy.
21. The highest heart rate value attainable during an all-out effort to the point of exhaustion.
22. An increase in heart rate during exercise to compensate for a decrease in stroke volume. This compensation helps maintain a constant cardiac output.

1. The process by which locally-released vasodilating substances in exercising muscle compete with and dominate the vasoconstrictor influence of sympathetic stimulation.
2. The mechanism by which an increased amount of blood in the ventricle causes a stronger ventricular contraction to increase the amount of blood ejected.
3. The heart rate at rest, averaging 60-80 beats/min.
4. The pressure exerted by the concentration of proteins in a solution, drawing water from regions with lower oncotic pressures.
5. The point at which the metabolic demands of exercise can no longer be met by available aerobic sources and at which an increase in anaerobic metabolism occurs, reflected by an increase in blood lactate concentration.
6. The ratio of the volume of air ventilated to the amount of carbon dioxide produced.
8. The pressure against which the heart must pump blood, determined by the peripheral resistance in the large arteries.
13. The maximal capacity to move air into and out of the lungs, usually measured for 12s and extrapolated to a per-minute value.
16. The process of holding the breath and attempting to compress the contents of the abdominal and thoracic cavities, causing increased intra-abdominal and intrathoracic pressure.
17. The mathematical product of heart rate X systolic blood pressure. Also called the double product.