QUESTION 38If the stroke volume is 80 mL and the end-systolic volume is 35 mL, then what was the end-diastolic volume? a.155 mL b.100 mL c.80 mL d.115 mL e.105 mL QUESTION 39Which types of receptors would NOT be found on the cells of the SA node? a.Nicotinic b.Muscarinic c.B1 adrenergic d.All of the above would be found e.None of the above would be found

The heart is a muscular organ that is present in the front and middle of the chest, just behind and slightly left to the breastbone. This organ plays a major role in pumping oxygenated blood and nutrients to all parts of the body. The cardiac cycle is defined as the term that refers to the performance of the heart. The cardiac cycle consists of two periods namely; the relaxation phase known as diastole and the contraction phase known as systole. Note: As per our guidelines, I am solving the first part. Please repost the second question separately.The amount of blood pumped into the pulmonary and systemic circuits per minute is called cardiac output (CO). On average, the human heart undergoes 60–80 cardiac cycles per minute. This value is known as heart rate (HR). Cardiac output also depends upon the amount of blood pumped in one heartbeat, which is called stroke volume. To calculate the cardiac output for one ventricle, both the parameters, heart rate, and stroke volume, is required. The value of heart rate is 72 beats per minute. Stroke volume can be calculated by subtracting end-systolic volume (ESV) from end-diastolic volume (EDV). In a normal heart, the value of ESV and EDV are 50 and 120 ml (milliliters), respectively. So, stroke volume can be calculated as: 80 = EDV - 35 80 + 35 = EDV 115 mL = EDV Hence, the correct option is option D = 115 mL