In August, Mrs. Cromwell, who is 85 years old. checked into the Cardiology lab at Stormont-Vail...
In August, Mrs. Cromwell, who is 85 years old. checked into the Cardiology lab at Stormont-Vail Medical Center in Topeka for a routine check-up. They measured her heart's end-diastolic volume at rest and then after 15 minutes on the treadmill. The term end-diastolic volume can be related to the size of the heart's ventricles at rest. When one exercises, the volume of the blood returning to the heart i.e. venous return) increases and thus the volume of the heart's ventricle expands. On the next page is a graph of the relationship between end-diastolic volume and the force of the contracting ventricles. Point A represents the volume of Mrs. Cromwell's heart at rest and point B is the value after exercise on the treadmill. Recently, she returned to the clinic because she collapsed at West Ridge Mall. She was complaining of fatigue and shortness of breath. When the doctors re-examined her (i.e. a new treadmill test), her end-diastolic volume was larger denoted by point C on the graph. Fill-out the chart and answer the questions on the next page based on your work in lab to this point in the course and the graph. End Diastolic Volume (ml) Force of Contraction (mN/mm Force of Contraction (mN/mm) 60 80 100 120 140 160 180 200 End Diastolic Volume (ml) a) Using the graph above, fill in the chart to the right of the graph with data. The values do not need to be exact just estimate. (1 pt) b) What is the independent variable in this study? _(1/2 pt) c) What is the dependent variable? (1/2 pt) d) Study the graph above and its general shape. During the last six weeks, what experiment did we do that intended to show a similar relationship? (1 pt) e) Based on your work in lab (note: knowledge of cardiac function not necessary). why did the force of contraction decrease from B to C? (2 pts)