Experiment 1 heart valves and pumps

Experiment 1Heart Valves and Pumps Experiment Inventory

Materials (2) Balloons (Only 1 balloon is required; an extra is provided in case the first balloon is compromised during the

procedure)

(1) Canning Jar

(2) Straws

(1) Skewer

(1) Ruler

(1) Waste Beaker (any volume)

*Tape

*Scissors

*Water Note: You must provide the materials listed in *red.

EXPERIMENT 1: HEART VALVES AND PUMPS The heart beats an average of 100,000 times and pumps approximately 7,571 liters of blood through its chambers daily. This is made possible by the intricate network of vascular pathways, arterial canals, and heart valves. This architecture is coupled to the heart’s electrochemical pumping system and a nest of cardiac muscle that contracts to pump blood toward the lungs and other organs.

Heart valves are flexible membranes that influence the directionality of blood through the heart. They expand when fluid is present and collapse when fluid departs. This dynamism prevents blood from retracing its route. In this experiment, you will explore the function of the heart valves and their role in pumping blood.

PROCEDURE 1. Use scissors to cut off the neck of the balloon but do not remove the main, circular section of the balloon. Set the balloon

and neck aside.

2. Fill the canning jar with water until it is approximately halfway full.

3. Fasten the circular section of the balloon around the top of the jar. The goal is to create a tight seal.

4. Use the skewer to poke two small holes in the balloon on the jar. These holes should be approximately 2 cm apart from each other.

5. Position one straw in each hole. This should create a tight fit and should not compromise the sealed environment.

Note: It is important that the holes for the straws are not so large that air can pass through. If the holes are too large, repeat Steps 1 – 5 with the second balloon.

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6. Rotate the end of one of the exposed straws by pulling on the accordion folds at the top of the straw and pressing down.

7. Retrieve the balloon neck (cut off in Step 1). Position the neck over the down-pointing straw.

8. Tape the neck to the straw to seal the connection. The neck should hang limp, forming a flap on the top of the straw. This constitutes your “valve.”

9. Position the waste beaker (any volume) beneath the valve.

10. Use your index finger to press on the balloon stretched over the jar. Continue to press and release the balloon until water moves through the straws. Record what happens in Table 2. If possible, record the amount of water that is displaced into the waste beaker.

11. Remove the tape and neck from the straw, and pour out the water from the waste beaker.

12. Repeat Step 10 without the neck. Record what happens in Table 2.

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Data Sheet Experiment 1 Data Sheet Table 2: Experimental Observations

Observations (with valve) and mL H2O Displaced

Observations (without valve) and mL H2O Displaced

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