CLASSROOM ACTIVITIES
Resting Heart Rate
Purpose: To learn how to measure your pulse or heart rate.
Materials: A stopwatch, a lab sheet, and a pencil.
Procedure:
1. Divide students into pairs. As one student takes their pulse one student will
time.
2. Students must then choose a pulse point on their body, which they will use to
detect their heart rate.
Finding Pulse Points and Your Heart Rate:
1. Feel with the fingertips of your index and middle finger for your pulse point until
you detect pulsations.
2. Keep yourself as still as possible while you are taking your heart rate.
3. Count the number of heartbeats you feel in one minute. Record the results.
4. Now repeat steps 1-3 measuring your heart rate at a different pulse point.
5. Repeat the procedure for your partner.
6. Graph and compare results.
Pressure
Purpose: To learn how to measure your blood pressure.
Materials: A sphygmomanometer (blood pressure cuff), a stethoscope, a lab sheet, and a pen or pencil.
Procedure:
1. Divide students into pairs.
2. One student will be the patient having his/her blood pressure measured. The other student will be the student doctor who measures the blood pressure.
3. Switch jobs.
How to measure blood pressure:
1. Student patient should extend arm on table with palm up.
2. Place blood pressure cuff above the bend in the arm. The cuff should be snug yet have enough room to insert two fingers.
3. Check to see if valve is open or closed.
4. Place stethoscope ear tips into ear.
5. Position stethoscope on arm to hear pulse.
6. Pump pressure up to 180 mm.
7. Release valve slowly.
8. The first pulse sound you hear as you release the valve is the systolic pressure. Have the student patient place their finger on the number of the first sound to mark the spot.
9. Continue to release the valve. Approximately 40 mm down from the first sound you will hear is called the diastolic pressure.
10. Record the systolic and the diastolic pressure on the chart.
11. Jog in place for two minutes.
12. Repeat steps 1-10.
13. Record results.
14. Make a bar graph of results.
15. Present, analyze, and compare results in class.
Factors Affecting Blood Pressure and Heart Rate
Purpose: To analyze the factors that may affect heart rate.
Materials (per group): A sphygmomanometer, a stethoscope, a clock or stopwatch, a student handout, a graph paper, and a pen or pencil.
Procedure:
1. Assign students to lab groups of four.
2. In your group choose two students to measure the heart rate and two students to
measure the blood pressure.
3. Heart rate pair: Take resting heart rate and record. Blood pressure pair: Take
resting blood pressure and record.
4. The group will then choose two factors that they believe will cause a change in
heart rate and blood pressure.
5. Test these factors and collect the data using time as an independent variable.
6. Graph and analyze results.
7. Present and compare results with class.
Flow Rate of Blood
Purpose: A lab activity for students to gain an understanding of the flow rate of blood
Procedure: When teaching the vascular system one can easily demonstrate the constriction of blood vessels by using different sizes (diameter) of PVC pipes and skittles or another candy the students may wish to eat. Using three different sizes of pipe 1", ½", and ¼" students will be given a bag of skittles and will have to determine how fast they can get all of the skittles through each size pipe as well as determining how many they could then get through in a full minute of time.
Students will discover that the larger diameter pipe allows fast movement of the particles (skittles) through the pipe while the smaller diameter pipe takes more time in order for the same amount of material to flow. Using this information, students can create a table that shows how many more of the smaller diameter pipes they would need in order to get the same amount of flow of particles in a 1 minute time period. This will help demonstrate and create the ideas behind the need for bifurcation of the vascular system.
Jell-O blood vessels
Purpose: An activity where students can study the flow rate of diffusion across different diameter semi-permeable membranes.
Materials: A tincture of iodine, cornstarch/water solution, plastic sandwich bags (cheap is good), and beakers or plastic cups.
Procedure (can be done by teacher or student): Fill beaker about halfway and put about ten drops of iodine. Put about a teaspoon of starch and about 50 ml of water in baggie and tie. (Actual measurements can vary) Put the baggie in the beaker and wait. In about 15 minutes the solution in the baggie will turn purple as a result of the iodine diffusing through the bag. You may want to discuss with students beforehand that iodine is an indicator for starch.
Possible discussion questions: The plastic bag is permeable to which substance? Why did the iodine enter the bag? Why didn't the starch enter the beaker? How is the plastic bag like the cell membrane?
Going Further
Using PVC pipes from blood velocity experiment use clear wrap inside of each pipe and fill completely with Jell-O. Before placing in refrigerator to gel fill a straw for each pipe with water and red food coloring capping both ends with clay and carefully place in center of each pipe (meaning pipes must stand up in refrigerator in order to gel).
For experimentation students remove Jell-O cast of pip and place in a tray. Student removes straw and caps hole where straw came out with clay leaving behind the dyed water. Students can then observe diffusion through the different thickness materials seeing that it will not completely diffuse through the largest diameter pipe, but will completely go through the smallest diameter pipe. This helps demonstrate the diffusion of oxygen through the blood vessels and shows that the arteries do need diffusion of oxygen in them in order for survival of smooth muscle cells, and also shows that the small capillaries will allow complete diffusion of oxygen across the capillary walls.
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