Cellular Basis for Cardiac Function and the
Relationship to Metabolic Rate
A lesson plan developed by the UW Science Posse
Grade Level
 9th-12th
Estimated Time
 5 class periods
Topics Covered
 Cardiac muscle anatomy
 Electrical excitement of cardiac cells
 Electrocardiograms (ECGs)
 Metabolic Rate
Standards and Benchmarks
 11.A.S.1.1 Students identify activities taking place in an organism related to
metabolic activities in cells.
 11.A.S.1.2 Students demonstrate the connections between natural selection and
survival.
 8.A.S.1.1 Students relate different organ systems with their specialized function.
Objectives / Enduring Ideas
 Students will understand the basics of heart anatomy and blood flow
 Students will learn how to interpret an ECG and calculate heart rate based on an
ECG
 Students will make and test predictions about how activities such as exercise and
diving may affect heart rate and metabolic rate.
 Students will be able to apply their newfound understanding of ECG’s and
metabolic rates to novel situations.
Learning Module 1: Engage (55 minutes)
Objectives
The students will be introduced to the basics of heart anatomy and physiology.
Materials
 Clock with a second hand
 Power point projector and computer
 Note cards and poster paper for concept maps
 PowerPoint File Learning Module 1: Cardiac Physiology
Vocabulary
Action Potential: A brief electrical signal of about 100 mV across the cell membrane of
a neuron or other excitable cell.
Atria & Ventricles: Primary chambers of the heart. Ventricles are typically much larger
than atria.
Atrioventricular (A-V) Node: A group of electrically conducting cells linking the atria
to the ventricles.
Electrocardiogram: A recording made of the total electrical activity of the heart.
Sinoatrial (S-A) Node: The primary pacemaker of the heart, located in the right atrial
wall in birds and mammals.
Activity One (5 minutes)
Start the presentation by asking students what their current heart rate is. After
several answers, have the students calculate their own heart rates by taking their pulses (#
of beats in 15 seconds multiplied by 4).
Activity Two (25 minutes)
Students should now be introduced to basic heart anatomy and the electrical
properties of cardiac muscle via the PowerPoint presentation (Learning Module 1:
Cardiac Physiology). Of key importance will be the concept of pacemaker cells and gap
junctions allowing for the electrical transduction involved in making our hearts beat.
Activity Three-Assessment (25 minutes)
Have the students utilize the remainder of the time period constructing concept
maps (in groups of 4 or 5) of heart anatomy and function. Students will be expected to
incorporate basic terminology covered in activity two including: Atria, Ventricles, gap
junctions, action potentials, p-waves, QRS complex, t-wave, arteries, veins, systole,
diastole, pacemaker, SA-node, AV-node, Bundle of HIS, Purkinje fibers,
electrocardiogram.
Learning Module 2: Explore (60 minutes)
Objectives
The students will be able to interpret a real-life ECG and make predictions based
on their previous introduction to cardiac physiology on what effects exercise and diving
may have on their electrocardiogram.
Materials
 3-4 laptops with Labscribe software installed.
 3-4 iWorx data acquisition boxes with ECG leads and gel electrodes
 3-4 jump ropes so students can exercise
 3-4 plastic tubs big enough for students to immerse their faces
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Computer connected to projector
PowerPoint File Learning Module 2: Measuring ECG’s
Word File Learning Module 2: Worksheet
Activity One (15 minutes)
Use the PowerPoint to remind the students how to measure heart rates with ECG
data. Ask the students to make some predictions on what kinds of activities might
influence heart rate. Ask the students why such activities change heart rate. Have the
students attach ECG leads and measure their own electrocardiogram (Note: split the
students into four groups first). Have the students record their data in the worksheet. As
an alternative, students can be given handouts containing ECG’s recorded
previously from other students.
Activity Two (20 minutes)
Equipped with a basic understanding of heart physiology, have the students make
predictions about how exercise and then diving might affect heart rate. Exercise can
consist of students jumping rope or running in place for 5 minutes. The dive test can be
achieved by having the students immerse their faces in cold water for several seconds.
Make sure the students write down their predictions and record the data in the worksheet.
As an alternative, data sheets containing real life ECG’s can also be handed out.
Students can still participate in the exercise and diving protocols by calculating
heart rates via pulse.
Activity Three-Assessment (20 minutes)
Following the experiments, have the students graph their data by group
(Depending on time, the students can either do this in the worksheet, or Excel). The data
can be split into 3 sections: resting heart rate, exercise heart rate, and diving heart rate.
Ask the students whether or not they should reject their null hypotheses based on the
data. Typically students should see a fairly clear increase in heart rate for the exercise
and a clear decrease for the diving bradycardia. This may be a good time to remind the
students about controls and experimental variables. You can also bring in the concept of
replication and variation in data sets. Finish by having the students write down why they
think heart rates changed the way they did.
Learning Module 3: Explain (55 minutes)
Objective
Students will gain an appreciation for how heart rates and ECG’s correspond to
the body’s demand for oxygen.
Materials
 4 1 gallon jugs, empty
 4 500 ml beakers or graduated cylinders
 Plastic tubing, approximately three feet in length
 4 permanent markers
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Anti-bacterial soap for cleaning tubing
4 plastic tubs capable of holding 3-4 gallons of water
Clock with a second hand
PowerPoint File Learning Module 3: Measuring Metabolic Rate
Word File Learning Module 3: Worksheet
Vocabulary
Metabolic Rate: the sum total of all chemical reactions taking place in our bodies at any
given time.
VO2: volume of oxygen consumed per unit time. Typically expressed in units of L O2 /
hour.
Tidal Volume: volume of air inhaled with each breath.
Respiratory Rate: number of breaths taken / minute.
Vital Capacity: maximal volume of air an individual can breathe in one breath.
Dead Space: the volume taken up by the trachea and non gas-exchanging portions of the
lung.
Total Lung Capacity: the sum of vital capacity and dead space.
Activity One (10 minutes)
Using the PowerPoint file, introduce the students to the concept of metabolic rate,
and various ways of measuring metabolic rate.
Activity Two (45 minutes)
Have the students construct their own “lungometers” out of empty one-gallon
jugs. Briefly this entails filling up the jugs in 500ml increments until full. Each 500ml
addition should be clearly marked with permanent markers. When the jug is full, the
students should turn it upside down and place in the plastic tub filled with approximately
1 gallon of water. Once in the water, the cap should be carefully removed and the plastic
tube inserted into the jug. If students place the tube in their mouth and breathe in through
their noses and out through their mouths, they will be able to measure how much air they
consume per unit time. Following a baseline measurement, have the students make a
prediction on how they think exercise will influence tidal volume, respiratory frequency,
and ultimately oxygen consumption. Finally, have the students exercise for 5 minutes
and make another measurement. Once again the students can plot their data as a class,
and compare this data set to their ECG data. 45 minutes.
Learning Module 4: Explore (55 minutes)
Objective: The objective of this learning module is to have the students apply what they
have learned about ECG’s to novel, real world examples.
Materials
 Word File Learning Module 4 Exploring ECGs in Nature
Activity One (30 minutes)
Students will be given several different real world scenarios that might be
expected to produce unique ECG’s including: a man with atrioventricular block, a person
suffering from Wolf-Parkinson-White, and a resting trout, trout out of water, and a
swimming trout. The worksheet is intended to reinforce ideas about the electrical
conductance of the heart in addition to showcasing how ECGs and cardiac physiology
differ in other vertebrates.
Activity Two (25 minutes)
As a group the students can discuss the various data sets and any problems they
had with the interpreting the scenarios. The students will also have the opportunity to
discuss other potentially interesting ECG scenarios. If available, have the students cruise
the internet for 10 minutes looking for any unusual ECGs (other animals, odd
circumstances, etc). Save enough time for the students to present their interesting ECGs
to the rest of the class.
Learning Module 5: Evaluate (35 minutes)
Objective: The objective of this learning module is to assess the students general
knowledge of heart function including: basic anatomy, electrical properties, ECG’s, the
relationship between heart rate and oxygen demands.
Materials
 Note cards and poster paper
 Learning Module 5: Evaluation
Activity One
Students will be divided into groups and be asked to write down what they think
are the most important points covered in the learning modules. Each group will be given
a broad topic area including: heart anatomy, electrical properties of heart, ECG’s, and the
relationship between heart rate and oxygen demand. The students can assemble a brief
hierarchy of concepts for each topic and then present them as groups to the rest of the
class. 20 minutes.
Activity Two
Students will be given a brief quiz that will encompass all of the concepts covered
in learning modules 1-4. Importance will be placed on students being able to apply their
newfound knowledge to novel settings. 15 minutes