Name KEY

Path of Blood in the Heart – 100 Informal Points (50 of the points come from the color-coded blood flow, box diagram.)

IntroductionAt the time of her death, Anna’s heart stopped beating. The body’s pump was no longer able to propel oxygen-rich blood to her tissues and cells. As you continue to piece together the circumstances of her untimely death, examine any evidence housed in Anna’s cardiovascular system, the system of the heart and the associated blood vessels, for additional clues.

The human heart is an amazing pump. Each beat correlates with the pumping action of the heart as it moves blood through the entire body. On average, a person’s heart beats 100,000 times each day. That is over 35 million beats a year and over 2.5 billion beats during an average lifetime. The human heart has to pump 5.6 liters (about six quarts) of blood every 20 seconds. In an average lifetime the heart pumps over 55 million gallons of blood. That is a lot of pumping!

The blood pumped by the heart carries many of the resources necessary for life, including nutrients, oxygen, and water, to your cells. The body’s cells must carry out many reactions in order to survive, grow, repair, or replicate. All of these processes require energy, and oxygen is required for cells to obtain energy. Therefore, all cells need a constant supply of oxygenated blood.

To understand the design of the heart, it is important to examine the structures of this incredible organ and trace the path of blood flow. In this activity you will investigate the basic structure of the heart as well as identify the major blood vessels that bring blood in and out of the heart’s main chambers. You will create a graphic organizer to help you remember the basic traffic pattern of blood flow to and from the heart and lungs .The diagrams you draw in this activity will help you to identify the actual structures of the heart when you dissect a four-chambered sheep’s heart in the next activity.

Procedure1. Open the NOVA Map of the Human Heart Interactive available at

http://www.pbs.org/wgbh/nova/body/map-human-heart.html(Note: You may have to try different browser to get one that works!)

2. Click on the Launch Interactive button to the right of the heart drawing.

3. Click the Track button to track the liters of blood your heart pumps while completing this interactive.

4. Click on the Anatomy tab to view the basic structures of the heart. Pay special attention to the information regarding the convention in naming the right and left sides of the heart. Return to this drawing as needed throughout the activity. In the space below explain why it appears as though the right side of the heart is on the left and the left side of the heart is on the right.

The heart is labeled based on the perspective of the patient. In your body the left side of the heart is on the left side of your body and the right side of the heart is on the right side of the body but when you are looking at a heart or a picture of a heart it is a mirror image.

5. Click on the Step Thru tab and follow the main steps as blood moves through the heart, lungs, and body. List these six steps in the table below.

Step Number Description

1

Oxygen-poor blood flows from the body into the right atrium.

2

Blood flows through the right atrium into the right ventricle.

3

The right ventricle pumps the blood to the lungs, where the blood releases waste gases and picks up oxygen.

4

The newly oxygen-rich blood returns to the heart and enters the left atrium.

5

Blood flows through the left atrium into the left ventricle.

6

The left ventricle pumps the oxygen-rick blood to all parts of the body.

6. In the space below answer the following question: Which side of the heart takes oxygen to the lungs and which side of the heart is responsible for delivering oxygen to the body?

The right side of your heart receives oxygen-poor blood from your veins and pumps it to your lungs, where it picks up oxygen and gets rid of carbon dioxide. The left side of your heart receives oxygen-rich blood from your lungs and pumps it through your arteries to the rest of your body.

The lungs have a direct supply of oxygen since this is the site of gas exchange during breathing.

7. Note the amount of blood (in liters) your blood has pumped before exiting the animation. Remember that a traditional soda bottle holds two liters.

Number of liters: ___________

8. Follow the directions below to create a simplified drawing of the heart showing the basic flow of blood through the organ. This “heart box” will be a general reference for you as you further explore the main blood vessels that serve the body and the heart. It is not designed to show you an anatomical drawing of the heart, but to help you remember key structures as well as the general flow of blood. NOTE: THIS ASSIGNMENT IS REPEATED NEXT YEAR IN HBS. MAKE THE BEST HEART BOX YOU CAN SO IT MAY BE RESUSED NEXT YEAR!!!

9. Use websites or a reference textbook to view the structure of the human heart and complete the remaining steps of the activity. Some suggested websites include:

Human Anatomy Online – Heart http://www.innerbody.com/image/card02.html

Get Body Smart: An Online Examination of Human Anatomy and Physiology http://www.getbodysmart.com/ap/circulatorysystem/heart/menu/menu.html

Texas Heart Institute – Heart Anatomy http://www.texasheartinstitute.org/HIC/Anatomy/anatomy2.cfm John Wiley and Sons, Inc. Blood Flow Through the Heart animation

http://www.sumanasinc.com/webcontent/animations/content/human_heart.html Yale University; Cardiothoracic Imaging: Gross Anatomy of the Heart at: http://www.yale.edu/imaging/anatomy/ant_heart_2/

10. Obtain a piece of plain white paper. Complete the drawing/labeling in pencil and then highlight with color at the end. (Note: You may want to do everything in pencil and then outline in color afterwards when you are confident in your diagram.)

11. Use a ruler to create a large table in the center of the paper as shown below.

12. Remember that there are four chambers in the human heart. Think about each square in the box as a chamber of the heart. Label the right and left atria as “RA” and “LA.” Label the right and left ventricle as “RV” and “LV.” Remember that you are looking at an illustration of someone else’s heart. Make sure you are clear as to which side is labeled as the right and which side is labeled as the left.

13. Review circulation in the body. Pulmonary circulation moves blood to the lungs to pick up oxygen and back to the heart so that oxygenated blood can be delivered. Systemic circulation pumps oxygen rich blood to the body and returns deoxygenated blood back to the heart to be sent out for refueling.

14. Use a ruler to create a smaller box on each side of the main box.

15. Determine which side of the heart is responsible for pulmonary circulation and which side is dedicated to systemic circulation. Label the appropriate side box “lungs” and the other box “body.” Add drawings to represent the lungs and the body.

16. Note that a series of tubes, or vessels, serve as the highways for the transportation of blood. Arteries are responsible for carrying blood away from the heart and veins are responsible for returning blood back to the heart.

17. Add the major blood vessels to your diagram. Refer to the resources in Step 9 for guidance if necessary. Draw tubes running from one box to another (outside the boxes) to show the path of the vessels listed below. Think about where each vessel starts and ends. For example, the pulmonary arteries move blood from the heart (the right ventricle) to the lungs to pick up oxygen. In this case you would draw a tube from the box representing your right ventricle to the box representing the lungs.

Pulmonary Artery Pulmonary Vein Aorta Superior and Inferior Vena Cava

18. Label each major blood vessel. Make sure the path you show on your diagram is accurate. Note that blood that is moving out of the ventricles actually moves up through the top of the heart. Major vessels do not leave the bottom of the heart as shown in their heart box. The diagram will simply help you remember the order of flow.

19. Add color to your diagram. Red is traditionally used to show oxygenated blood, and blue is used to show blood that is oxygen deficient, or deoxygenated. Color chambers and vessels according to the type of blood they carry. But remember, this coloring scheme is used to help you visualize differences. Your blood is never blue! Deoxygenated blood is dark red, which appears blue when viewed through the skin.

20. Note that throughout the heart there is a system of valves. Review the structure and function of heart valves using the websites listed in Step 9 or other reliable sources.

21. Add the following valves to the appropriate places on your diagram. Use small lines to show flaps or cusps of the valve. Label each valve.

o Tricuspid Valveo Mitral (Bicuspid) Valveo Pulmonary Valveo Aortic Valve

22. Imagine you are a red blood cell sitting in the right atria of the heart. In the space below, write an essay that describes what happens to this red blood cell as it moves through the body. Be as specific and grammatically correct as possible. What structures will it pass through? How will it interact with oxygen? Think back to the last unit, Unit 3: Sickle Cell Anemia, and make sure to include the word hemoglobin in your response.

The red blood cell is in the right atria, meaning it is currently deoxygenated and in the pulmonary circulation circuit. At this time the hemoglobin is not binding O2, but the red blood cell is carrying CO2 waste, in the form of bicarbonate (HCO3

-), to the lungs to be exhaled. The red blood cell moves from the right atrium to the right ventricle via the tricuspid valve. From there it passes through the pulmonary valve into the pulmonary artery. The next stop is the lungs where the respiratory system meets the circulatory system. The CO2 passes from the capillaries in the circulatory system into the alveoli of the respiratory system so that it can be exhaled. At the same time inhaled O2 passes from the alveoli into the capillaries to enter the circulatory system. The O2 binds to the iron on the hemoglobin in the red blood cells. The blood is now “oxygenated.” The red blood cell now enters the left side of the heart and systemic circulation as it enters the pulmonary vein. From there it travels to the left atrium and then on to the left ventricle via the mitral (also known as the bicuspid) valve. From there it passes through the aortic valve and into the aorta. From here the red blood cell travels via the circulatory system to all parts of the body where the O2 is unloaded by diffusing through the capillary membranes as well as the cell membranes to enter the body cell. CO2 waste is picked up from the body cell and loaded into the red blood cell in the form of bicarbonate. The blood at this time is said to be “deoxygenated” and must travel back to the lungs so that the CO2 may be exhaled. It travels back to the lungs via the right side of the heart and pulmonary circulation. It flows through the superior and inferior vena cavas into the right atrium, which is where the story began so the red blood cell has come full circle!

*Note: Carbon Dioxide (CO2) is a toxic gas at a high concentration, so must be carried in the form of bicarbonate (HCO3

-) to safely travel through the blood stream.

Circulatory System meeting the Respiratory System: (Both capillaries and alveoli have membranes that are only one cell thick, making gas exchange quick, easy and efficient!)

23. Label the structures and vessels listed on your heart box on the heart diagram below. You will use this diagram as a reference throughout this unit so please keep this activity handout in a convenient location.

Conclusion Questions 1. Which chamber of the heart do you think is the most muscular? Explain your reasoning.

The left ventricle because it must contract with the most force to pump blood throughout the whole body.

2. A growing fetus has a vessel, the ductus arteriosus, in the heart that connects the pulmonary artery with the aorta and conducts blood directly from the right ventricle to the aorta. Why do you think this vessel closes soon after birth?

The ductus arteriosus closes off after birth so that blood can flow properly through the heart. While in utero, a baby’s ductus arteriosus connects the pulmonary artery to the aorta so that blood is shunted from the developing lungs of the fetus. This way the baby can get oxygen form its mother through the placenta. After birth the baby breathes in his/her own oxygen.

3. In most of the body, the arteries carry oxygenated blood and the veins carry deoxygenated blood. The exception to this pattern is the heart. Explain how and why specific arteries and veins of the heart are different from the pattern seen in the rest of the body.

Pulmonary Circulation: Blood flowing through the pulmonary artery is deoxygenated. Blood flowing through the pulmonary vein is oxygenated.

4. Describe the mechanisms in place to prevent the blood from flowing in the wrong direction through the heart.

Valves prevent blood from flowing in the wrong direction (or backwards) in the heart. The valves are held in the proper place because of the chordae tendinae.

5. Explain what happens to tissues, such as the heart, or the brain, if oxygenated blood is not delivered in a timely manner.

Cells within those structures will be starved of oxygen and will not be able to perform cellular respiration, which means they will not be able to make ATP. ATP is the only energy the cell can use so they will not be able to function.