What happens to our bodies when we exercise? In this chapter we will use BOSON modules to make a heart rate detector to monitor our heartbeat, by which to explore the internal balance during the process of exercise.
NGSS - NEXT GENERATION SCIENCE STANDARDS
HS-LS1-3 From Molecules to Organisms: Structures and Processes
Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis.
The human body is a complex system that is kept healthy and survives through a mechanism called homeostasis. Homeostasis is the body making adjustments to keep us safe and comfortable. For example, your body likes to be in a “Goldie Locks” temperature range that is not too hot and not too cold. To stay in this comfortable temperature range, your body will shiver when it is cold and sweat when it is hot. This is just one example of a negative feedback loop the body uses to maintain homeostasis. Negative feedback loops work to minimize the effect of a change to the system. For your body, they are safety mechanisms that are used to keep your body in ideal conditions. Temperature is one factor the body must keep constant but there are others as well.
What will happen to your body if you do some exercise?
When you exercise, you are increasing the demand for oxygen and decreasing the oxygen concentration in your blood. The body responds by breathing faster and deeper, thereby taking in more oxygen and countering the decrease in oxygen. The blood also starts to circulate faster in order to get rid of the extra carbon dioxide produced by cellular respiration. This means the heart will start beating faster.
What will happen to your heart rate if you do some exercise?
1. Find your heartbeat with your fingers. You can place them on your carotid artery in your neck, or the artery in your wrist.
2. Find a stopwatch and time the number of beats in 10 seconds.
3. Multiply the number of beats by 6 to find your beats per minute.
4. Now, jump up and down for 1 minute.
5. Repeat steps 1-3.
6. Compare the 2 values: Which one is higher?
Building a heart rate monitor with the Boson Kit will give you a much clearer picture of your heart rate by automatically counting your heart beats for you.
1.Connect the Battery Holder and two Module Cables to the Mainboard.
2. Connect the Heart Rate Sensor to the input side of the Mainboard with a Module Cable.
3. Connect the OLED Module to the output side of the Mainboard with a Module Cable.
4. Press the button on the OLED Module until the screen turns on.
1.Press a finger on the heart rate sensor, measure data three times and take the average value.
Tip: please apply moderate pressure on the sensor. Take the average value from multiple measurements can ensure the accuracy of the recorded data.
2.Do an exercise, and measure the heart rate in 3, 6 and 9 minutes.
3.Repeat steps 1-2, and select different sports every time.
Copy the Data Table below into your notebook.
In your groups discuss the following questions:
1. What was the effect of increased exercise on heart rate? Was there a positive/negative correlation?
2. Justify your results with the information from the activity and from what you know about exercise and your heart.
3. Compare your results with the rest of your class. Did they match up?
4. What would you say is your greatest source of error and how would you improve next time?
●Cellular Nutrition and Waste
Increased Heart Rate During Exercise & Maintaining Homeostasis
During exercise, your heart rate increases to maintain a state of balance, known as homeostasis."Homeostasis" means balance or equilibrium. How your body works to maintain equilibrium is reflected in how your vital signs vary with activity. Heart rate, blood pressure and respiration are lowest during periods of rest and sleep. During exercise, blood pressure, pulse and respiration increase to meet the increased demand for oxygen and nutrients by your musculoskeletal system. The adjustment of vital signs to match your body's level of physical activity is an example of homeostasis in action.
Metabolism is the rate at which cells of your body consume oxygen and nutrition. The increased demand of muscle cells for oxygen and nutrients during exercise is a state of increased metabolism. Homeostasis is maintained when your heart can provide the rate of blood flow necessary to meet your body's increased metabolic demand for oxygen and nutrients.
Homeostasis, Cellular Nutrition and Waste
Exercise increases the production of cellular wastes such as carbon dioxide and lactic acid. Your cardiovascular system maintains homeostasis between the delivery of oxygen and nutrients and the removal of cellular wastes by increasing your heart rate. Your increased heart rate speeds up delivery of oxygen and nutrient rich blood to your musculoskeletal system while increasing the rate at which blood is taken away from tissues and delivered to the lungs to receive oxygen.
Homeostasis and Blood Flow
The total amount of blood in a human body remains the same during exercise. To maintain homeostasis, your body redistributes blood flow. During exercise, blood flow to the nervous system, gastrointestinal tract, kidneys, brain and spleen decreases, while blood flow to the musculoskeletal system increases.
Metabolic processes generate heat. The cardiovascular system helps to maintain homeostasis with respect to body temperature. An increased heart rate increases the delivery of blood to your skin. Increased blood flow to your skin and sweating causes dissipation of heat, and body temperature remains within normal limits.
Consider the following questions:
1. According to your experimental data, which exercise can maximize your metabolism?
2. Can you explain why different hearts and body systems respond to the same stimulus differently?