Keeps on Pumpin'

 Objective Students will measure and calculate heart rates per minute and for other units of time. They will determine the amount of blood pumped by their heart during various intervals of time.

Key Questions

• How many times will your heart beat in 80 years?
• how much blood is pumped with each beat?

Materials

For every student

• plastic cup
• copy of "Keeps on Pumpin" worksheet

For every two students

• calculator
• plastic cup filled with water
• measuring tape or meter stick

For the class

• clock or watch with a second hand or a digital reading
• water pitchers
• kilogram scale
• nomogram (included in kit)

Procedure

Determine your "at rest" heart rate, then extrapolate to beats per hour and beyond.

 Enter your age: Enter the number of beats in 15 seconds: Press CALCULATE to see your beats per minute: (per minute): (per hour): (per day): (per year): (in your lifetime):

How much blood does your heart pump in one minute? This is called cardiac output.

To calculate cardiac output you need to know your body surface area in square meters and your cardiac index (how much blood is pumped per minute for every square meter of body surface area).

To find your body's surface area, first use the scale and measuring tape to determine your weight in kilograms and your height in centimeters.

Weight =____ (kilos) Height = ____(cm)

On a nomogram, find your weight in the right column and your height in the left column. Place a straightedge on the nomogram so the weight and height are connected. The point where the straightedge crosses the center column denotes your body's surface area in square meters.

How much blood the heart pumps for every square meter of surface area (cardiac index) varies with the age of the individual. For children ages 10­13, the average cardiac index is 2.75 liters/m2/minute at a resting state.

Multiply your body surface area by the cardiac index (2.75 l/m2/minute) to determine the liters of blood pumped by your heart in one minute (cardiac output).

2/minute= ____liters per minute.

How does your volume per minute compare to a 2 liter beverage bottle?

.How much blood is pumped in an hour and in a day?

How much blood does your heart pump in one beat? This volume is called stroke volume.How would you calculate stroke volume? (Answer: liters pumped per minute divided by beats per minute).

Convert the stroke volume to milliliters.

____liters per minute x 1000 = ____ml per beat

Use a graduated cylinder to carefully measure this amount of water. Pour it into a cup. This is the volume of blood pumped by your heart in one beat. Compare this to the volumes of other classmates.

Extensions

A mouse's heart beats about 700 times per minute and an elephant's about 30. A mouse lives less than three years, an elephant more than 60. What's the connection?

Compare the heart rates of various animals. Is there a relationship between size of animal and heart rate?

Research the longevity of various animals and compare this to their heart rate. Is there a relationship between the average lifetime of an animal and its heart rate?

Notes to the teacher:

Over 1,500 Gallons of Blood Pumped Daily
The heart is a powerful muscle that beats without stopping throughout a lifetime. It pumps about 55-80 ml (1/3 cup) of blood with each beat for adults and around 25-85 ml per beat for children. An adult heart pumps about 6,000-7,500 liters (1,500-2,000 gallons) of blood daily. The average adult body contains about five quarts of blood which continually circulates throughout the body. The shortest trip to the heart muscles takes only a few seconds. The trip to the toes takes over a minute.

How Your Heart Works: Interesting Heart Facts

http://www.howstuffworks.com/heart6.htm Dr. Carl Bianco, M.D., is at it again, as he informs his fantastic fans about the heart's fabulous, fun facts.

The Implantation of a Heartmate

http://www.smm.org/studio3d/julie/heartmate.htm
A live video of the implantation of a heartmate!

Heart Transplant

http://www.smm.org/studio3d/julie/mov/julie/htransplant.htm
A live video of a heart transplant!

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