dccc the heart & ekg #4 cardiovascular i the heart &...

Bio 151 – Laboratory Manual Human Anatomy & Physiology II DCCC The Heart & EKG

Last updated 08/2019

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#4 Cardiovascular I – The Heart & EKG

Objectives:

Identify a list of human heart structures using a

virtual human dissection

Dissect a sheep heart to identify external and

internal structures

Identify a list of human heart structures on a model

Perform an EKG under different conditions

(lying down, sitting up, deep breathing)

Understand the parts of the EKG

Analyze the duration of the EKG waves

Equipment: Remember to bring gloves, goggles,

dissecting kit, appropriate shoes, photographic atlas.

Prelab Activity: This may be checked by your instructor at the beginning of lab! Create hypotheses for the EKG experiments by filling in the following sentences (use: go up, go

down, or stay the same).

A. The heart rate (BPM) sitting up will _________________________ compared to lying down.

B. As heart rate (BMP) goes up, deltaT (pg 9, Fig 8) will _________________________.

C. The time for the p-wave while lying down will ___________________compared to sitting up.

D. The heart rate (BPM) during inhaling will ______________________ compared to exhaling.

I. Introduction

The heart has four chambers – two upper atria (singular, atrium) and two lower ventricles. Blood

enters the atria from the large veins and passes into the ventricles before being ejected from the

heart within the large arteries to either the lungs or the rest of the body (Fig. 1).

II. Virtual Human Heart Examination

Preparation

1. Start the Anatomy & Physiology Revealed®

software by double clicking the icon.

2. On the home screen, from Module (top center) select

Cardiovascular from the drop down Menu.

3. From the icon list at the top center, click the left most icon

(the dissection icon).

Figure 1. Structures of the human heart



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4. Under the Structure List column (top left) use the

Topic drop down menu to choose Thorax.

5. From the View drop down menu choose Arteries-

anterior. Do not select a Structure Type at this point.

6. At the bottom of the left column are the layer tools.

Move the red arrows down to gradually remove each layer

of the body. The layers must be removed in order. Remove

Layers 1 and 2 to visualize the pericardium in Layer 3.

7. To identify visible structures within a layer,

click on the radio button at the top of the layer

that is on display. Pins will appear marking

labeled structures.

8. Hover over a pin and the name of the structure

will appear. Or click on a pin and the structure will

be highlighted in the main view and further

information on the structure will appear in the

various boxes in the left column. Another

identification method is to click on the name of the

structure in the information section.

9. Practice using the layer tools and highlighting structures by clicking on the pin or name.

III. Virtual Human Heart Examination

Cardiovascular system, thorax, arteries-anterior, dissection layer 3

Structures AP Revealed®

1. pericardium (also

known as pericardial sac)

1. The introductory instructions

on page 2 will bring you to

this view (APR Fig. 1).

2. Note the position of the heart

within the thoracic cavity.

3. The heart is enclosed in the

double-layered pericardium

(APR Fig. 1).

APR Fig.1

1



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2. heart

3. aorta

a. aortic arch

b. brachiocephalic

artery

c. left common carotid

artery

d. left subclavian

artery

4. pulmonary trunk

5. vena cava

a. superior

b. inferior (not shown)

1. Use the layer tool to move one

layer deeper (Layer 4). The

pericardium is removed in

this layer revealing the major

vessels associated with the

heart (APR Fig. 2).

2. Use the labeling pins to locate

the aorta (3), superior vena

cava (5a), and pulmonary

trunk (4).

3. Note: the vessels branching

from the aorta are labeled in

APR Fig 3.

APR Fig. 2



3. aorta

a. aortic arch

b. brachiocephalic

artery

c. left common carotid

artery

d. left subclavian

artery

1. Use the layer tool to move to

Layer 5 (APR Fig. 3).

2. The anterior veins have been

removed to reveal the arteries

branching from the aortic

arch.

3. Locate the aorta arch (3a),

brachiocephalic (3b), left

common carotid (3c), and left

subclavian (3d) a.

APR Fig. 3

Cardiovascular system, heart, vasculature-anterior, dissection layer 2


6. coronary arteries

a. right

b. left

7. pulmonary arteries (not shown in this

view)

8. right and left

pulmonary veins (right

shown in this view)

1. To see the heart details, choose

Heart from the Topic drop down

menu in the left column. Choose

Vasculature-anterior under the

View menu. Move to Layer 2

(APR Fig. 4).

2. Use the labeling pins for all

three layers to locate the

structures on the left.

Also shown in this view are the cut

end of the superior and inferior vena

cavae (5a,b).

APR Fig. 4

2

3

5

a

2

4

3c 3b 3d

3

a

5b

6a

5a

6b 8



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Cardiovascular system, heart, internal features-anterior, dissection layer 1


9. auricle

a. right

b. left

10. ventricle

a. right

b. left

11. apex

1. Choose Heart from the Topic

menu and Internal features-

anterior from the View menu

(APR Fig. 5).

2. Use the labeling pins to locate

the structures on the left

APR Fig.5

Cardiovascular system, heart, internal features-anterior, dissection layer 5


12. atrium (atria, pl.)

a. right

b. left

13. interventricular

septum

14. atrioventricular

valve

a. right (tricuspid)

b. left (bicuspid)

15. papillary muscle

16. chordae tendineae

17. semilunar valve

a. pulmonary (not

visible in this figure)

b. aortic

1. Move to Layer 5 (APR Fig. 6).

2. In this view, move up and

down through Layers 2-6 to find

the appropriate labeling pins for

the structures on the left.

APR Fig. 6

III. Sheep Heart Dissection

A. Preparation

1. Wear goggles, gloves, and an apron for the entire time that you are working with

preserved specimens.

2. Obtain a dissecting tray and a sheep heart.

B. Exterior Observations

auricles (right and left)

ventricles (right and left)

apex

pulmonary trunk

aorta

9a

9b

10a

10b

11

12a

16

13

12b

14a

17b

14b

15



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Use your atlas to orient the heart. The prominent features on the anterior surface are the left

auricle and the pulmonary trunk. Most of the vessels will emerge on the posterior surface,

however, they might have been cut close to the heart and only the openings will be visible. The

apex is composed of the left ventricle.

*Check with your instructor that you have the heart correctly oriented before you cut the heart.

C. Interior Observations

atria (right and left)

ventricles (right and left)

interventricular septum

atrioventricular valves

tricuspid (right)

bicuspid/mitral (left)

semilunar valves

aortic

pulmonary

chordae tendineae

papillary muscle

FRONTAL SECTION:

1. *Make sure to be very careful with your scalpel. Never cut towards your body or hands /

fingers. Be very careful also when cleaning the scalpel. Never touch the blade or move it near

you or others.

2. To start, place the heart flat on the dissection pan

with

the apex towards you and the base away from you.

Do NOT hold the heart in your hand.

3. Keep the heart steady by placing the flat of your

palm (the hand without the scalpel) on the anterior

surface of the heart with your finger-tips raised off of the heart’s surface. Your scalpel should

never be near your hand or fingers. You are cutting on the plane between the bench and your

hand.

4. Cut the heart first from base to apex. Make a frontal section with your scalpel by cutting

through the center of the auricle toward the apex. Turn the heart so that the apex is at the top

and continue the cut through the apex and down through the opposite auricle. If needed, finish

the cut through the interventricular septum and base to cut the heart completely into two halves.

Note that the heart is asymmetrical. The left ventricle makes up apex, is the largest chamber of

the heart with the thickest wall. The interventricular septum separates the two ventricles. The

right ventricle is slightly posterior to the left ventricle and much smaller. Locate the

atrioventricular valves between the atria and ventricles. The chordae tendineae are attached to the

inferior aspect of the valves. Papillary muscles bind the chordae tendineae to the ventricle walls.

The aortic and pulmonary semilunar valves are at the junction of the ventricles with the aorta and



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pulmonary trunk, respectively. Confirm the location of each vessel by inserting a blunt probe

through the atria. Find all the structures on your Interior Observation list. In order to see the

pulmonary semilunar valve you may have to cut through the pulmonary trunk on the anterior

surface.

D. Directions for Cleaning Up

1. All specimen tissue should be thrown away as directed by your instructor. Please do NOT

allow tissue to end up in the sink. It will clog the drain and cause extra work for lab assistants.

2. Thoroughly wash your dissecting tray with soap and water, dry, and return it to the lab bench

where you found it.

3. Carefully clean your dissecting tools keeping the scalpel blade –away- from your skin.

4. Use the spray disinfectant cleaner provided to thoroughly wipe down your lab bench area so

that it will be ready for the next group of students.

5. Dispose of your gloves, paper towels and old plastic bags in the regular trash containers,

NOT the red biohazard containers.

6. Make sure that you take your dissecting kit and goggles with you when you leave the lab.

IV. Human Heart Model Observation

Locate the following structures on the human heart model:

aorta

─ brachiocephalic artery

─ left common carotid artery

─ left subclavian artery

pulmonary trunk

vena cava

─ superior

─ inferior

auricle

─ right

─ left

ventricle

─ right

─ left

apex

pulmonary arteries

pulmonary veins

atria

─ right

─ left

interventricular septum

atrioventricular valve

─ right (tricuspid)

─ left (bicuspid or mitral)

papillary muscle

chordae tendineae

semilunar valve

─ pulmonary

─ aortic

V. EKG using BIOPAC®

The electrocardiograph (ECG or more commonly known

as EKG) measures the electrical activity of the heart.

The waveforms represent the electrical activity of the

heart which occurs just prior to the contraction /

relaxation of the cardiac muscle. The P-wave represents

the depolarization of the atria just prior to atrial systole

(contraction), QRS complex – the depolarization of the

Figure 2. The EKG waveform.



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ventricles, and the T-wave – repolarization of the ventricles (Figure 2). The repolarization of the

atria is obscured by the electrical activity of the ventricles.

Electrodes or leads are placed on the skin in a pattern. Several lead patterns can be used

including a 12, 5, and 3 lead placement. Figure 3 indicates the

placement of the electrodes for a three (3) lead EKG. We will

measure our EKG while lying down, sitting quietly, and after

exercise. FOLLOW the directions below carefully.

BIOPAC® Equipment Setup:

1. The BIOPAC® MP45 unit will already be plugged into the

computer and attached to the electrodes (Channel 1).

2. Log on to the computer using your DCCC login so that you

may print your results at the end.

3. Start the BIOPAC® Student Lab program by finding the icon on the desktop and double-

clicking it.

4. Select the lesson: L05 - (ECG) I (click OK).

5. Type in a name for the file you will recognize (ie. the subject’s name) (click OK).

Subject Preparation:

1. Place the leads on the subject as shown in Figure 3. Make sure that the flat side with the metal

is against the skin and that the cords are not twisted. The leg leads should be placed on the

medial surface of the leg just above the ankle. The arm lead should be placed on the forearm just

above the wrist. Remove jewelry as it may cause recording errors.

2. The subject should lie quietly on the mat and avoid moving or talking during calibration and

data collection.

*Note: You will perform ALL the recordings first and then proceed to analyze the data.

Calibration:

1. When the equipment is

ready and subject is still,

click Calibrate (upper left).

It will stop automatically at 8

seconds.

2. Observe the calibration

data recorded on the screen. Figure 4. Calibration screen.

Figure 3. Electrode (lead)

placement for the EKG.



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It should look similar to Figure 4, and if so, Continue to the next section. If the data do not

appear similar, click Redo Calibration.

Lying Down (Supine)

1. When the subject is still, click Record and collect data for 20 more seconds. The time in

seconds passes on the bottom.

2. Click Suspend when the time reaches 28 seconds.

3. The data should appear similar to the calibration. If so, click Continue to go to “Sitting up”.

If the data appear abnormal, click Redo when the subject is ready and repeat steps 2 & 3.

Sitting up with normal breathing

1. Next have the subject sit on a chair. The subject must remain still (movements of the arms and

legs may cause unwanted changes in the recording).

2. When the subject is sitting in the chair and still, click Record and collect data for 20 more

seconds. The time in seconds passes on the bottom.

3. Click Suspend when the time reaches 48 seconds.

4. The data should still appear regular and similar to the calibration recording. If so, click

Continue to go to “Deep Breathing”. If the data appear abnormal, click Redo when the subject is

ready and repeat steps 2-4.

Deep Breathing

1.Be ready to take 5 slow deep breaths. You will note the inhale start by clicking F4 and the

exhale start by clicking F5.

2. Click Continue to start collecting data for 5 slow deep breaths.

F4 – inhale start F5 – exhale start

3. Click Suspend when all five breaths are completed.

4. The data should still appear regular and similar to the calibration recording, If so, click Done

and remove the electrodes.

If the data appear abnormal, click Redo (upper left) when the subject is ready and repeat steps

1-4.

After you click, Done, a window will pop-up. Click, yes to save the data.

To continue to data analysis, click, Analyze current data file.

Data Analysis Figure 5. Data analysis tools.



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Preparing the Data

1. In the far right side of the recording window,

are the tools you will use to help analyze your data (Figure 5).

2. The time in seconds is shown on the scroll bar at the bottom of the recording window. Go to

the 8-28 second recording segment where the subject was “lying down” (Figure 6).

Figure 6. Diagram of recording segments.

3. Using the magnifying tool , click on the first waves that were produced until you can see

only about 5-8 wave patterns. The data will at this point appear strange - follow step 4.

4. At the top of the screen, select the Display menu and then click on Autoscale Waveforms (top

left). Repeat magnify and

Autoscale waveforms until

the data appears similar to

Figure 7.

If you need to go back, click,

Display, and then zoom

previous to undo your

previous zoom or Display,

autoscale horizontal to see

the whole data set again to

start the procedure over

again.

Figure 7. Data analysis screen.



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Analysis: Lying down (Supine)

Heart Rate

1. Using the I-beam tool ,

select one waveform to

measure. Click and drag from

one peak (R) to the next peak

(R) to select this interval (see

Figure 8). This is called the R-

R value and represents the time

between heart beats (deltaT)

and the computer will calculate

the heart rate (BPM).

2. In Table 1, record the measurements for deltaT and BPM from the corresponding boxes at the

top of the screen. This is sample 1. Repeat this process for one more waveform, recording the

value in Table 1. Round each number off to the nearest 0.01 place.

Analysis: Components of the EKG

1. Using the I-beam tool, select each

component of the EKG waveform: P-

wave (Figure 9), QRS complex (Figure

10), and T-wave (Figure 11) individually

in sequence, and record their durations

(deltaT) as waveform 1 in Table 1.

Repeat for one more waveform. The

waveforms chosen may be the same as in

the R-R measurements. Again, round off

to the nearest 0.01.

Figure 8. R-R measurement.

Figure 9. P-wave selection.



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Analysis: Sitting up

Use the scroll bar at the bottom of the recording window (see Figure 12), to go to the recording

segment when the subject was Sitting Up (28-48 seconds). A black vertical bar denotes where a

new recording starts (Figure 12). Repeat the procedures to measure heart rate, duration, and EKG

components as for Lying down. Record your measurements in Table 2.

Analysis: Deep Breathing

Use the scroll bar at the bottom of the recording window, to go to the recording segment Deep

Breathing (48-about 108 seconds, Figure 12). A black vertical bar denotes where a new

recording starts (Figure 12).

Repeat the above procedures to measure heart rate (BPM) and duration (deltaT) only following

the directions below:

*Make only one EKG measurement for each inhale and exhale segment – giving a total of 4

EKG measurements inhaling and 4 for exhaling. You will not need to use one of the segments

if you recorded 5 breaths.

The beginning / end of each segment is marked by small triangles at the top (Figure 12 –

arrows at top). Scroll to find the next triangle showing the start of the next segment.

Record your measurements (to the nearest 0.01) in Table 3.

Figure 11. T-wave selection.

Figure 10. QRS complex selection.



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Print a copy of your last recording screen (Deep Breathing) for each member of your group.

Click: Print, Preferences, Landscape (leave the setting on Visible Only).

Label one heart beat on your EKG as shown in Figure 2 and attach to your lab report.

When Finished, click File and then Quit to exit the program.

The first Inhale segment

Figure 12. Deep Breathing segment

Scroll bar

New recording

segment

beginning

Bio 151 – Laboratory Manual Human Anatomy & Physiology II DCCC Cardiovascular I – The Heart Name:_________________________


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Laboratory #4 Report

For each label in the human heart figure, write the name of the structure on the correct line

below. Use the labels from the lists in the laboratory activity. Indicate Left and Right as needed.

A. _____________________________

B. _____________________________

C. _____________________________

D. _____________________________

E. _____________________________

F. _____________________________

G. _____________________________

H. _____________________________

I. _____________________________

J. _____________________________

K. _____________________________

L. _____________________________

M. _____________________________

N. _____________________________

O. _____________________________

P. _____________________________



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Part V. EKG using BIOPAC©

Table 1. Lying Down / Supine

Table 2. Sitting Up

Heart rate and duration.

Measurement waveform 1 waveform 2 Average

Duration (R-R)

deltaT(seconds)

Heart rate

(BPM)

Components of the EKG


P-wave

deltaT(seconds)

QRS complex

deltaT(seconds)

T-wave

deltaT(seconds)



Duration (R-R)

deltaT(seconds)

Heart rate

(BPM)

Components of the EKG


P-wave

deltaT(seconds)

QRS complex

deltaT(seconds)

T-wave

deltaT(seconds)



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Table 3. Deep Breathing

A. EKG Questions

1. Under which condition (1 or 2) was the pulse rate slowest? _______________

2. Is this what you hypothesized? _________________________________________

3. Was your hypothesis about deep breathing correct? _______________

4. What does the p-wave represent? _________________________________________

5. Does the duration (deltaT) of the p-wave change much? _______________________

B. Look up the following:

6. What is an arrhythmia?______________________________________________________

7. Atrial flutter:______________________________________________________________

8. Ventricular fibrillation:______________________________________________________

9. Long QT syndrome (LQTS):_________________________________________________

10. Which of the above arrhythmias is depicted in B?______________________________


Measurement Inhale 1 Inhale 2 Inhale 3 Inhale 4 Average

Duration (R-R)

deltaT(seconds)

Heart rate

(BPM)

Exhale 1 Exhale 2 Exhale 3 Exhale 4 Average

Duration (R-R)

deltaT(seconds)

Heart rate

(BPM)

dccc the heart & ekg #4 cardiovascular i the heart &...

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