1. Both the quadriplegic individual and the individual with the heart transplant have the same heart rate at different workloads. The heart transplantation has no parasympathetic and no sympathetic response and only a venous pump controlled by motor function this explains the steady rise in heart rate, as there is a little change in maximum and minimum heart rates, only 20bpm, due to absents of an autonomic response. The individual with quadriplegia has no motor functions (venous pump not working) therefore the heart rate works quicker with only the slightest increase in work rate. Although the heart rate is brought down to 80bpm, lower than the individual with heart transplantation due to him having parasympathetic responses on the heart. In the absence of cardiac parasympathetic innervations there is no rapid increase of the HR (as there are no sympathetic or parasympathetic responses); instead there is a steady increase in HR as seen with the individual with the heart transplantation.
2. The heart rates are both similar (about 120bpm) although the work loads are different. Both do not have sympathetic innervations to the heart and thus activation of cardiac sympathetic efferent activ
return and thus can achieve more work (higher oxygen consumption); although they are both limited in that they have no sympathetic response. The increase in heart rate in the individual with the heart transplant is also due to adrenalin from the adrenal medulla that acts on the heart upon sympathetic stimulation.
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