Final answer:
The equation Heart Rate x Stroke Volume = Cardiac Output is true. Cardiac output may decrease when heart rate exceeds 160 bpm. The heart consists of cardiac muscle, and sprinting is anaerobic.
Step-by-step explanation:
The equation Heart Rate (HR) x Stroke Volume (SV) = Cardiac Output (Q) is true. Cardiac output is the volume of blood pumped by the heart in one minute, and it can be calculated by multiplying the heart rate by the stroke volume.
When the heart rate increases above 160 beats per minute (bpm), the cardiac output does not necessarily increase. At very high heart rates, the heart may not have enough time to fill up with blood, which can cause stroke volume to decrease, potentially reducing cardiac output. So, the answer to what happens to cardiac output when heart rate increases above 160 bpm might be that it decreases (option b).
The heart consists of cardiac muscle tissue, not smooth muscle, so the statement is false. Sprinting is an anaerobic exercise because it involves short bursts of high intensity that do not rely primarily on oxygen consumption for energy production, so the statement is true.
The phase of the cardiac cycle where the heart contracts is called systole. During systole, the blood is ejected from the ventricles and circulates throughout the body. The statement about the circulatory system that is false is option a, as blood in the pulmonary veins is oxygenated, not deoxygenated.