Materials:- A clock with a second hand, or a digital watch or timer.
Procedure:1. Help the students locate their pulse points either on their wrists or necks. Select 4 students to be the patients and 4 students to be the nurses. Ask the nurses to place their right index and middle finger on the palm side of their patient’s left wrist. On the neck, the pulse point is located beneath the ear and jawbone (the carotid artery.)
2. Have the nurses check the pulse of the patients. They should turn the patient’s left hand palm-side up, and then place the first two fingers of your right hand along the outer edge of your left wrist just below where your wrist and thumb meet. Have 2 nurses check the carotid pulse and 2 nurses check the pulse at the wrist.
3. Slide their fingers toward the center of the patient’s wrist. They should feel the pulse between the wrist bone and the tendon.
4. Press down with our fingers until you feel your pulse. Do not press too hard, or you will not be able to feel the pulsation. Feel free to move your fingers until the pulse is easiest to feel.
5. Ask the nurses to count the number of beats in 15 seconds. Multiply this by four (15x4=60, there are 60 seconds in one minute). This is how many times the heart beats in one minute. (Student pulse rates at rest will vary between 50 - 110 beats per minute. Adult rates are lower.)
6. Do some exercise such as running in place, jumping jacks, or other exercise for one minute. Stop and calculate pulse again over 15 seconds. Calculate the heart rate for each activity.
7. Why might the heart rate be higher after exercise? How might a person get their resting heart rate to be lower? What other changes did you notice after exercising? Why might this be occurring?
Explanation:During each heartbeat, the muscles of the heart contract causing a wave of pressure which forces blood through the arteries. This wave of pressure is known as a pulse. There is one pulsation for each heartbeat. The pulse can be felt at various points on the body where the arteries are just under the skin, such as the temples, neck, elbow, wrist, groin, back of the knee, and the inside back of the ankle. The normal pulse rate varies with age.
With exercise or physical activity, the heart rate increases to supply the muscles with more oxygen to produce extra energy. The heart can beat up to 200 times per minute with extreme exercise. The brain sends nerve signals to the heart to control the rate. The body also produces chemical hormones, such as adrenaline, which can change the heart rate. When we are excited, scared, or anxious our heart gets a signal to beat faster. A trained athlete's heart can pump more blood with each beat so his or her heart rate is slower. Likewise, an athlete's recovery time is shorter. There are two ways the heart can meet the body's need for oxygen during exercise. It can beat faster or it can beat harder, moving more blood per pump. But it can only beat harder if it has been strengthened through regular exercise.
Why is this a worthwhile Hook Activity?This activity is directly linked to the curriculum expectation and leads into later lessons (circulatory system). This is an event that will get the students up and out of their seats to learn and can be conducted without materials. Students are engaged due to the fact that students are typically intrinsically motivated to learn about themselves. A self discovery event provides them with a quantitative measurement related to their own body.
Worthwhile Hook Questions: 1. Why does exercise increase heart rate?
2. What other body measurements increase during exercise?
3. If exercise increases your heart rate, would you expect an athlete to have an increased or decreased heart rate?
4. Who might need to know how to check heart rate?
Course: SBI3U
Expectation: E2 Developing skills of investigation and communication
E2.3 Use medical equipment to monitor the functional responses of the respiratory and circulatory systems to external stimuli.
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