BIOS255 Week 2 Cardiovascular System: Heart

Learning outcomes:

Identify the chambers of the heart.

Identify the location and function of valves within the heart.

Describe the flow of blood through the heart.

Define stroke volume and cardiac output.

Understand how the cardiovascular system responds to exercise.

Understand how cardiac output and blood pressure can be measured.

Understand how heart rate, stroke volume and cardiac output change with exercise.

Introduction:

The heart is a strong muscular pump with 2 complementary sets of vessels: one for the systemic and one for the pulmonary circulation. The pumping of the heart is essential in the delivery of oxygen to the millions of cells of the body and in the removal of their waste products. The heart pushes deoxygenated blood to the lungs and oxygenated blood around the entire body. It must continually beat to sustain life and so its muscular walls are made of specialized cardiac muscle cells that carry their own intrinsic contractile rhythm.

All cells within the body must be supplied with enough oxygenated blood each minute to meet their cellular metabolic demands. During exercise and processes such as tissue repair, cells are metabolically active and require more oxygen from the blood, thus increasing the workload of the heart. At rest, the metabolic demands of cells are less and therefore the heart doesn’t need to work as hard to supply them with the oxygen they require. The body must adapt to these changing requirements. Cardiac output is a measure of the flow of blood. We will examine the variables that make up the cardiac output, learn how to measure these variables, and then put some experiment subjects to work to see how exercise alters cardiovascular function. Lets head to the cardiac exercise lab!

Assignment:

Part 1: Complete Labster Cardiovascular function during exercise: learn how your body responds to exercise

As you complete the lab, have the lab report ready to record data. The theory section is a good resource.

Part 2: Complete the Lab report.

Heart Lab report

1. What measurements did you obtain from the test subjects? (1 point)

2. Record the data: (3 points)

HR at rest

HR max exercise

SV at rest

SV max exercise

CO at rest

CO max exercise

Subject A

Subject E

3. a. Define stroke volume in words. (1 point)

b. What is a normal stroke volume at rest in a healthy individual? (1 point)

4. a. Define cardiac output in words. (1 point)

b. Define cardiac output with the equation. (1 point)

c. What is a normal cardiac output at rest in a health individual? (1 point)

d. How does an increase in heart rate affect cardiac output (assuming no change in stroke volume)? (1 point)

5. Given that cardiac output did not increase as much as oxygen consumption rate (which increased 8x), what is the most likely mechanism that could allow increased oxygen delivery by the cardiovascular system? (1 point)

6. Compare the change in heart rate and stroke volume and cardiac output with exercise between Subject A and Subject E. What does this suggest regarding the health of the heart of Subject E? (1 point)

7. Describe the flow of blood, in order, starting at the superior vena cava, through the heart, to the lungs. Continue with the flow of blood from the lungs to and through the heart to the aorta.

Include the 4 chambers of the heart, the 4 valves, and the major blood vessels entering or leaving the heart. (3 points)

Grading Rubric for Lab Report

Activity

Deliverable

Points

Part 1

Complete Labster

15

Part 2

Complete lab report

15

Total

Complete all lab activities

30

Abbreviations:

HR=heart rate

SV=stroke volume

CO=cardiac output