Transcript Bio102_Lab6

Bio102
Laboratory 6
Blood Pressure
ECG (EKG)
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Objectives for Today’s Lab
• Blood Pressure
– Become familiar with determining pulse rate
– Become familiar with taking a blood pressure reading and with using a
sphygmomanometer (<- can you spell this? )
– Correlate the effects of various experimental conditions on pulse and
blood pressure
• ECG
– Acquire a better understanding of the theory behind the ECG
– Record and analyze an ECG
– Computers set up in lab
– You will conduct a one-lead ECG on a lab partner
– Identify the components (waves, intevals) of a normal ECG
– Describe the phases of the cardiac cycle represented by each wave form on
the ECG
– Calculate heart rate from an ECG
– Identify the beginning and end of the PR, QRS, and QT intervals
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Location of
Pressure Points
Temporal artery
Facial artery
External Carotid
artery
Brachial artery
Radial artery
Femoral artery
Pulse =
# beats/30 sec X 2
Dorsalis pedis
artery
Popliteal artery
Posterior tibial artery
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Pulse in Lab Today
• Use the radial artery of your partner, and use
your index finger
• Note the characteristics of the pulse
– Regular, irregular
– Strong, weak
• Count number of pulses in 30 sec. and multiply
by 2 to get the pulse rate
• Do this sitting down, standing up, and after
exercise
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Heart Sounds
Lubb (S1)
• first heart sound
• occurs during
ventricular
contraction
• A-V valves closing
Dupp (S2)
• second heart sound
• occurs during
ventricular relaxation
• semilunar valves
closing
♥
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Heart Sounds
Listening to the heart
(auscultation) is done using a
stethoscope (can you spell
this?)
Because sounds must pass
through several layers of
tissue, sounds are not heard
directly above their point of
origin
S1 = “Lubb” (1 looks like L)
S2 = “Dupp” (2 curved like D)
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Heart Sounds
Auscultate over the
left sternal border
about the level of the
3rd or 4th rib
Find the point where
you can hear the
sounds the best, and
use that
Remember: lubb-dupp <pause> lubb-dupp <pause> …
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Auscultatory Method of Determining Blood Pressure
Use an average bp from two
different readings from both
arms.
Do this standing up, sitting
down, and after exercise
Korotkoff sounds…
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For the BP portion of today’s today…
• If you need a bit of background and haven’t read it
already, take a look at the first few pages of today’s
handout
• Also see Marieb’s Lab Manual, pp. 501-508
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Great Book on Cardiovascular Physiology
Excellent reference for
cardiovascular physiology
Author: R. E. Klabunde
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A GREAT Book on ECGs
This is you after reading
the book…confident and
no longer intimidated by
ECGs!!
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Millivolts
Electrocardiogram
Time
PR Interval: 0.12 – 0.20 sec
QT Interval: 0.20 – 0.40 sec
QRS Interval: < 0.10 sec
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
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The Bipolar Limb Leads
We will be using only Lead II today, so the right
arm will be negative, and the foot will be
considered positive
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The Electrocardiogram
A wave of the ECG will be positive
(up) when the positive wave is
moving toward the positive electrode
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Electrocardiogram and Heart Events
Right
Arm
(-)
Left
Foot (+)
Recall that the left foot electrode is POSITIVE, so
when the wave of depolarization is moving toward the
left foot, we get a positive (up) deflection on the ECG
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Electrocardiogram and Heart Events
Right
Arm
(-)
Remember that the T-wave
represents repolarization of
the ventricles.
Left Foot
(+)
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ECG Animation…
NYU ECG tutorial site…
This is available on Links to Explore for Lab 6
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The Paper Chart ECG
Small boxes are
usually 1 mm on
each side
Ten mm high
represents 1 mV
0.2 sec
0.04 sec
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The Paper ECG Chart
How long is the PR interval on this strip? The QT interval?
(See Marieb’s Lab Manual pg. 461-462 for further explanation of
these)
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Calculating the Heart Rate
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Calculation of Heart Rate
As shown in the sample ECG below, you will calculate your heart rate by
measuring the time between 5-8 beats of your heart (4 beats shown below).
Then, to determine your heart rate from that, use the following proportion:
Beats measured (beats) * 60 seconds / Total time measured (sec) = Heart rate
(bpm)
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For the ECG portion of today’s lab…
• If you haven’t read it already and need a bit of background, see
Marieb’s Laboratory Manual pp. 461-464
• Run the ECGs for each member of your group by following the
Procedure in your handout
– Follow the instructions for the PowerLab ECG module in your handout
• Be sure electrode placement is correct
• Input the correct bioamp settings to reduce interference
• Be sure to record values you measure on the EGG on the computer
while you have them on the screen, and then transfer them to the
ECG strip after you print it
• Print each person’s ECG and directly on the printed ECG
– Show calculations for the heart rate
– Mark the PR, QRS, and QT intervals on hard copy with their
times (that you recorded when they were on the screen)
– Indicate the P, QRS, and T waves and what they mean
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What you should do in lab today…
• After EACH member of your group has an
ECG recorded, be sure to SAVE the ECG
into a file until the lab is over (just in case)
– Select File | Save As (to prevent overwriting
someone else’s file with your data)
– Enter a file name using your first and last name
with no spaces as the file name, e.g., SueCidal).
– File is saved to the Desktop, so when you retrieve
it later to analyze the data , LOOK ON THE
DESKTOP!
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Next Lab…
• Lab 7 - Microcirculation
– We will be examining the circulation in arterioles,
capillaries, and venules
• In a goldfish tail (a real one; not the cracker)
• Examining the effect of various substances/factors on
circulation
– See the handout online
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