Exam 23: Circulation

Which of the following statements regarding blood pressure is false?

You are dissecting a "mystery animal" in biology lab and discover that it has a series of closed blood vessels, a pair of lungs, two atria, and a single ventricle. What animal are you dissecting?

Ron and Tiffany are studying circulatory system function. They designed an experiment to test whether the diameter of a tube affects the rate of flow through the tube. In their experiment, they ran water from a large container through five tubes with different diameters for exactly 30 seconds for each tube. They measured the volume of liquid that passed through the tube during the 30-second period, testing each tube three times and pouring the water back into the container after each test. The results of the experiment are shown in the following table. Diameter of Average Volume Tube () Fluid (mL) Tube A 0.5 210 Tube B 0.6 350 Tube C 0.7 480 Tube D 0.8 600 Tube E 0.9 975 -Which statement best summarizes the results of the experiment?

To evaluate cardiac function, scientists and physicians measure both the pressure and the volume inside the heart. When both pressure and volume data are plotted on the same graph, the resulting graph is called a pressure-volume loop. To create a pressure-volume loop, a catheter (a thin tube) is inserted into the vessels of the heart, and measurements of both left ventricular pressure and left ventricular volume are taken. The data are plotted on a graph, and cardiac function can then be evaluated from the distribution of the data and the shape of the loop. The following figure shows a typical left ventricle pressure-volume loop for a healthy young adult. The cardiac cycle proceeds counterclockwise. Each complete turn around the loop (for example, starting at point A and ending back at point A) represents one complete cardiac cycle. -Aortic stenosis is a disease in which the aortic valve (the semilunar valve between the left ventricle and the aorta) narrows, resulting in increased left ventricular pressure and reduced ejection volume (the amount of blood that the left ventricle ejects). What would the pressure-volume graph for a patient with aortic stenosis look like compared to the graph shown above for a healthy young adult?

Which of the following is a function of the circulatory system?

Ron and Tiffany are studying circulatory system function. They designed an experiment to test whether the diameter of a tube affects the rate of flow through the tube. In their experiment, they ran water from a large container through five tubes with different diameters for exactly 30 seconds for each tube. They measured the volume of liquid that passed through the tube during the 30-second period, testing each tube three times and pouring the water back into the container after each test. The results of the experiment are shown in the following table. Diameter of Average Volume Tube () Fluid (mL) Tube A 0.5 210 Tube B 0.6 350 Tube C 0.7 480 Tube D 0.8 600 Tube E 0.9 975 -The results suggest that the smallest flow volume would be found in the ________ of the human body.

At any given time, what percentage of the body's capillaries have blood flowing through them?

During which phase of the heartbeat do the ventricles fill with blood?

Electrocardiographs (ECGs or EKGs) provide data about the electrical activity of the heart. By placing a series of "leads" on a person's chest, the electrical activity of the heart can be recorded and analyzed in order to detect irregular heartbeats (arrhythmias) and other conditions. The figure below shows a normal EKG tracing for one cardiac cycle. The P region represents electrical activity spreading through the atria. The QRS region represents electrical activity spreading through the ventricles. The T region represents electrical activity in the ventricles returning to rest. -What is happening in the heart during the QRS region?

The main function of the AV node is to

To evaluate cardiac function, scientists and physicians measure both the pressure and the volume inside the heart. When both pressure and volume data are plotted on the same graph, the resulting graph is called a pressure-volume loop. To create a pressure-volume loop, a catheter (a thin tube) is inserted into the vessels of the heart, and measurements of both left ventricular pressure and left ventricular volume are taken. The data are plotted on a graph, and cardiac function can then be evaluated from the distribution of the data and the shape of the loop. The following figure shows a typical left ventricle pressure-volume loop for a healthy young adult. The cardiac cycle proceeds counterclockwise. Each complete turn around the loop (for example, starting at point A and ending back at point A) represents one complete cardiac cycle. -At what point on the diagram does the aortic valve (the semilunar valve that separates the left ventricle and the aorta) open?

Which of the following is the cause of more than half of all deaths in the United States?

During exercise, your cardiac output can increase dramatically in order to meet the metabolic demands of your tissues. If your heart rate increased to 150 beats per minute and the volume of blood pumped per beat is 75 mL, what is your cardiac output?

Hematocrit is the percentage of red blood cells in the blood. In adult humans, hematocrit is roughly 40-45%, but it can be much higher or lower in other animals. Consider the Weddell seal, a mammal that can dive and hold its breath underwater for upwards of 80 minutes. What is the hematocrit level of a Weddell seal, and why?

From the left ventricle, oxygen-rich blood flows through the

You conduct a study with mice to determine whether giving them air with a higher-than-normal oxygen level results in their having a higher-than-normal oxygen content in their blood. What vessel should you draw blood from if you want to measure the highest potential level of oxygen content in the blood?

In which part of this figure would blood have the highest oxygen content?

Which part of this figure depicts an arteriole?

Blood clots are formed by platelets and the plasma protein

The location of the heart's pacemaker is a specialized region of cardiac muscle called the