Human Nerve Chapter. Experiment HH-1: The Electrocardiogram and Peripheral Circulation. Answer Sheet for Experiment HM-1

Transcription

1 Contents Human Heart Chapter Experiment HH-1: The Electrocardiogram and Peripheral Circulation Answer Sheet for Experiment HH-1 Experiment HH-2: The Electrocardiogram and Heart Sounds Answer Sheet for Experiment HH-2 Experiment HH-3: Exercise, the Electrocardiogram, and Peripheral Circulation Answer Sheet for Experiment HH-3 Experiment HH-4: The Six-Lead Electrocardiogram Answer Sheet for Experiment HH-4 Experiment HH-5: The Diving Reflex Answer Sheet for Experiment HH-5 Experiment HH-6: Heart Rate Variability (HRV) Answer Sheet for Experiment HH-6 Human Circulation Chapter Experiment HC-1: Blood Pressure, Peripheral Circulation, and Body Position Answer Sheet for Experiment HC-1 Experiment HC-2: Blood Pressure, Peripheral Circulation, and Imposed Conditions Answer Sheet for Experiment HC-2 Experiment HC-3: Pulse Wave Velocity Answer Sheet for Experiment HC-3 Experiment HC-4: Pulse Contour Analysis Answer Sheet for Experiment HC-4 Human Exercise Chapter Experiment HE-1: Metabolic and Thermal Response to Exercise Answer Sheet for Experiment HE-1 Experiment HE-2: Recovery from Exercise Answer Sheet for Experiment HE-2 Human Kidney Chapter Experiment HK-1: Human Kidney Answer Sheet for Experiment HK-1 Human Nerve Chapter Experiment HN-1: Auditory and Visual Reflexes Answer Sheet for Experiment HN-1 Experiment HN-2: Stretch Receptors and Reflexes Answer Sheet for Experiment HN-2 Human Muscle Chapter Experiment HM-1: Grip Strength and Electromyogram (EMG) Activity Answer Sheet for Experiment HM-1 Page IG-HH-1 IG-HH-1 IG-HH-3 IG-HH-6 IG-HH-8 IG-HH-10 IG-HH-12 IG-HH-14 IG-HH-16 IG-HH-18 IG-HH-19 IG-HH-20 IG-HH-22 IG-HC-1 IG-HC-1 IG-HC-3 IG-HC-5 IG-HC-7 IG-HC-12 IG-HC-13 IG-HC-14 IG-HC-15 IG-HE-1 IG-HE-1 IG-HE-3 IG-HE-4 IG-HE-5 IG-HK-1 IG-HK-1 IG-HK-2 IG-HN-1 IG-HN-1 IG-HN-2 IG-HN-4 IG-HN-5 IG-HM-1 IG-HM-3 Table of Contents i

2 Experiment HM-2: Electromyogram (EMG) Activity in Antagonistic Muscles IG-HM-6 Answer Sheet for Experiment HM-2 IG-HM-7 Experiment HM-3: Oculomotor Muscle Activity IG-HM-9 Answer Sheet for Experiment HM-3 IG-HM-11 Experiment HM-4: Stimulus Response, Work, Summation, and Tetanus in Human Muscle IG-HM-13 Answer Sheet for Experiment HM-4 IG-HM-15 Human Spirometry Chapter Experiment HS-1: Breathing Parameters at Rest and After Exercise Answer Sheet for Experiment HS-1 Experiment HS-2: Breathing and Gravity Answer Sheet for Experiment HS-2 Experiment HS-3: Factors that Affect Breathing Patterns Answer Sheet for Experiment HS-3 Experiment HS-4: Lung Volumes and Heart Rate Answer Sheet for Experiment HS-4 IG-HS-1 IG-HS-1 IG-HS-3 IG-HS-5 IG-HS-6 IG-HS-8 IG-HS-10 IG-HS-13 IG-HS-15 Human Psychophysiology Chapter IG-HP-1 Experiment HP-1: The Electroencephalogram (EEG) IG-HP-1 Answer Sheet for Experiment HP-1 IG-HP-3 Experiment HP-2: The Galvanic Skin Response (GSR) and Emotion IG-HP-8 Answer Sheet for Experiment HP-2 IG-HP-9 Experiment HP-3: The Galvanic Skin Response, Deception, Cognitive Complexity, and Vigilance IG-HP-11 Answer Sheet for Experiment HP-3 IG-HP-12 Experiment HP-4: Skin Temperature, Stress, Calming, and Embarrassment IG-HP-15 Answer Sheet for Experiment HP-4 IG-HP-17 Experiment HP-5: Heart Rate, Blood Pressure, and Vagal Tone IG-HP-20 Answer Sheet for Experiment HP-5 IG-HP-22 Experiment HP-6: Cynicism/ Hostility and the Hot Reactor IG-HP-24 Answer Sheet for Experiment HP-6 IG-HP-26 Cellular Metabolism Chapter Experiment CM-1: Oxygen Consumption and Size Answer Sheet for Experiment CM-1 Experiment CM-2: Mitochondrial Metabolism Answer Sheet for Experiment CM-2: Mitochondrial Metabolism Animal Nerve Chapter Experiment AN-1: Membrane Potentials Answer Sheet for Experiment AN-1 Experiment AN-2: Compound Action Potentials Answer Sheet for Experiment AN-2 Experiment AN-3: Neuromuscular Studies Answer Sheet for Experiment AN-3 Animal Muscle Chapter Experiment AM-1: Skeletal Muscle, Weight and Work Answer Sheet for Experiment AM-1 Table of Contents IG-CM-1 IG-CM-1 IG-CM-2 IG-CM-3 IG-CM-4 IG-AN-1 IG-AN-1 IG-AN-2 IG-AN-4 IG-AN-6 IG-AN-9 IG-AN-11 IG-AM-1 IG-AM-1 IG-AM-2 ii

3 Experiment AM-2: Skeletal Muscle, Summation and Tetanus Answer Sheet for Experiment AM-2 Experiment AM-3: Heart Muscle Answer Sheet for Experiment AM-3 Experiment AM-4: Uterine Motility Answer Sheet for Experiment AM-4 Experiment AM-5: Intestinal Motility Answer Sheet for Experiment AM-5 Animal Fluid Balance Chapter Experiment FB-1: Osmoregulation Answer Sheet for Experiment FB-1 IG-AM-4 IG-AM-5 IG-AM-7 IG-AM-9 IG-AM-13 IG-AM-15 IG-AM-18 IG-AM-21 IG-FB-1 IG-FB-1 IG-FB-2 Table of Contents iii

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5 Human Heart Chapter Experiment HH-1: The Electrocardiogram and Peripheral Circulation Background 1 The average heart rate, in beats per minute (BPM), is: Males, resting: approximately BPM. Females,. resting: approximately BPM. Fetal: approximately BPM. 2 The heart rate, which is expressed in beats per minute (BPM), and calculated from the average beat period by using the following equation: Heart Rate (BPM) = 60 seconds/minute For example: 60 seconds/minute = 67.4 beats/minute # seconds/beat 0.89 seconds/beat 3 The average R-Pulse interval is about 230 msec. Exercise 1: The ECG and the Pulse in a Resting Subject 1 What electrical and mechanical events take place during the R wave? The R wave corresponds to ventricular depolarization. In order for depolarization of the SA (sinoatrial) node to occur, Ca 2+ channel need to open, K + channels close, and slow Na + channels also open. After the chemical channels have caused depolarization, the wave spreads to the AV (atrioventricular) node and the depolarization wave continues to the Bundle of His and Purkinje fibers. This causes the contraction and emptying of the ventricles while the atria are refilling. 2 What events take place in the cardiovascular system during the R and pulse waves? The QRS complex results from the depolarization of the ventricles which precedes ventricular contraction. On the pulse wave, the peak of the curve will occur immediately after the R wave of the QRS complex. The contraction of the ventricles happens immediately after the closing of the AV valves and the rise o ventricular pressure. This causes the semilunar valves to open and the blood is pushed out of the ventricles into the waiting arteries. 3 The signal recorded on the Pulse channel is rate of change of the blood pressure entering the subject s fingertip. When this signal is integrated, the waveform displayed on Pulse Integral channel is similar to an arterial pressure curve. Is there a short plateau or dip during each cycle displayed on the Pulse Integral channel? This plateau or dip is called the dicrotic notch. If you optimized the tension on the plethysmograph strap to record a large, clean pulse wave from your subject, you should see a dicrotic notch on the Pulse Integral channel. The dicrotic notch is seen as a small dip and then rise in the curve on the Pulse Integral Channel. 4 What event recorded on the ECG channel corresponds to the dicrotic notch? What causes a dicrotic notch? The event on the ECG Channel that corresponds to the dicrotic notch is the downward slope of the T-wave, which represents early diastole and the repolarization of the ventricles. The cause of the dicrotic notch is the brief rise of aortic pressure as blood pushes against the closed semilunar valves at the end of the T wave, causing the bump that you see in the Pulse Integral channel. Exercise 2: The ECG and the Pulse in Other Subjects 1 Is the time interval between the R wave and the peak of the pulse wave the same for each subject? Does this time interval differ with heart rate? The time interval will vary between subjects based on health, fitness levels, and gender. This time interval may differ with changes in heart rate, but should be fairly consistent with each level of activity. 2 Do you see any differences in the size or shape of dicrotic notches from different subjects? Remember: the tension on the plethysmograph strap affects the shape of the pulse recording. There will be differences in the shape and size of the dicrotic notch between individuals, again based on health, fitness levels, and gender. However, the general shape should be a slight dip in the curve and then a slight bump upwards on the Pulse Integral Channel. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-1

6 3 Is the time interval between the peak of the pulse wave and the bottom of the dicrotic notch the same for each subject? As with all individuals, you will see variety in the time interval between the peak of the pulse wave and the bottom of the dicrotic notch. However, each person s time interval should be consistent with each level of activity. 4 What factors would affect the shape or position of the dicrotic notch? Some factors that could affect the shape of the dicrotic notch would be: a diseased or damaged heart, high or low blood pressure, irregular heart rhythms, and heart murmurs or incompetent valves. Exercise 3: The Effect of Cold on the Pulse 1 What effect does cooling have on the amplitude of the pulse wave? Cooling tends to decrease the amplitude of the pulse wave over the long term. There will be a consistent decrease in pulse wave amplitude the longer the body is exposed to cold temperatures. 2 Does cooling of the forearm affect the heart rate, or the time interval between the R wave and the peak of the pulse wave? Heart rate may increase at first, but over time there will be a continual decrease. The time interval between R waves will increase, showing a longer time between ventricular contractions, and thus a longer time interval between the pulse waves. 3 Through what mechanism does cooling affect the peripheral circulation? Cooling will decrease the diameter of the blood vessels causing less blood to be moved around the body. This decrease in blood circulation causes the heart to slow down and therefore not pump as much blood through the smaller blood vessels. 4 What other factors may affect peripheral circulation? Peripheral circulation may be affected by: blood pressure, diet, atherosclerosis (arteriosclerosis), exercise fitness and general overall health factors. Exercise 4: The Effect of Heat on the Pulse 1 What effect does warming have on the amplitude of the pulse wave? Warming tends to increase the amplitude of the pulse wave over the long term. There will be a consistent increase in pulse wave amplitude the longer the body is exposed to warm temperatures. 2 Does warming of the forearm affect the heart rate, or the time interval between the R wave and the peak of the pulse wave? Heart rate will increase at first, but over time there will may be a leveling off of the rate unless the body goes into heat exhaustion and heat shock due to overly hot temperatures. The time interval between R waves will decrease, showing a shorter time between ventricular contractions, and thus a shorter time interval between the pulse waves. 3 Through what mechanism does warming affect the peripheral circulation? Warming will increase the diameter of the blood vessels causing more blood to be moved around the body. This increase in blood circulation causes the heart to beat faster and increase peripheral circulation to keep up with the need to move a greater amount of blood around the body. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-2

7 Name Lab Section Answer Sheet for Experiment HH-1: The Electrocardiogram and Peripheral Circulation Exercise 1: The ECG and the Pulse in a Resting Subject 1 What electrical and mechanical events take place during the R wave? 2 What events take place in the cardiovascular system during the R and pulse waves? 3 The signal recorded on the Pulse channel is rate of change of the blood pressure entering the subject s fingertip. When this signal is integrated, the waveform displayed on Pulse Integral channel is similar to an arterial pressure curve. Is there a short plateau or dip during each cycle displayed on the Pulse Integral channel? 4 What event recorded on the ECG channel corresponds to the dicrotic notch? What causes a dicrotic notch? Exercise 2: The ECG and the Pulse in Other Subjects 1 Is the time interval between the R wave and the peak of the pulse wave the same for each subject? Does this time interval differ with heart rate? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-3

8 2 Do you see any differences in the size or shape of dicrotic notches from different subjects? Remember: the tension on the plethysmograph strap affects the shape of the pulse recording. 3 Is the time interval between the peak of the pulse wave and the bottom of the dicrotic notch the same for each subject? 4 What factors would affect the shape or position of the dicrotic notch? Exercise 3: The Effect of Cold on the Pulse 1 What effect does cooling have on the amplitude of the pulse wave? 2 Does cooling of the forearm affect the heart rate, or the time interval between the R wave and the peak of the pulse wave? 3 Through what mechanism does cooling affect the peripheral circulation? 4 What other factors may affect peripheral circulation? Exercise 4: The Effect of Heat on the Pulse 1 What effect does warming have on the amplitude of the pulse wave? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-4

9 2 Does warming of the forearm affect the heart rate, or the time interval between the R wave and the peak of the pulse wave? 3 Through what mechanism does warming affect the peripheral circulation? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-5

10 Experiment HH-2: The Electrocardiogram and Heart Sounds Background 1 The average amplitudes of the waves in a normal ECG are: P wave: 0.25mV R wave: 1.0mV T wave: mV 2 The average heart rate, in beats per minute (BPM), is: Males, resting: approximately BPM. Females,. resting: approximately BPM. Fetal: approximately BPM. 3 The heart rate, which is expressed in beats per minute (BPM), and calculated from the average beat period by using the following equation: Heart Rate (BPM) = 60 seconds/minute For example: 60 seconds/minute = 67.4 beats/minute # seconds/beat 0.89 seconds/beat Exercise 1: The ECG in a Resting Subject 1 Is the amplitude of each wave (P, QRS, T) always the same in different cardiac cycles? Each individual s cardiac cycles will show a small variation between wave amplitudes. However, this difference should be minor and you should not see huge swings between cardiac cycles. P wave: The depolarization of the SA node through the atria. Amplitude = 0.25 mv. Lasts approximately seconds. Atria contract at about 0.1 seconds after the start of the P wave. QRS Complex: This is the result of the depolarization of the ventricles. Lasts approximately seconds. Q wave: Atrial repolarization (tends to be very small). R wave: Ventricular depolarization (the largest wave), Amplitude = 1.0mV. S wave: Complete ventricular depolarization leading to ventricular contraction T wave: The repolarization of the ventricles and heart recovery. Amplitude = mV. Lasts from seconds. 2 Which wave has the largest amplitude? Usually, the R wave has the highest amplitude and the T wave has the second highest. The P wave has the lowest amplitude of the 3 main waves. 3 What is the average resting heart rate of the subject? Males: bpm Females: bpm Exercise 2: ECG Recordings from Other Subjects 1 Do the P waves of different subjects have the same amplitude? The QRS complexes? The T waves? Why? Different subjects will have different amplitude values of their ECG waves. This is due to level of fitness, age, weight, smoking and a variety of other factors. All wave amplitudes of healthy individuals should fall into a small range that helps determine their level of cardiac fitness. 2 For each subject, determine the wave with the largest amplitude. Is this result the same for all individuals? The R wave will have the highest amplitude. This should be the highest wave in all individuals. 3 Is the heart rate the same for each individual? Heart rate will vary between individuals based on fitness levels, age, weight, etc. 4 What is the range of resting heart rates within the class? Resting heart rates can range from as low as 40 bpm, in incredibly fit individuals and trained athletes, to as high as 90 bpm. Tachycardia is a resting heart rate that is higher than 100 bpm. Bradycardia is a resting heart rate that is lower than 60 bpm. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-6

11 5 Are there any obvious correlations between resting heart rate and gender, apparent fitness, or diet of your subjects? To determine apparent fitness, the class may want to compose a list of questions that will allow you to assign a relative fitness factor to each subject. You should see a difference in average resting heart rate between males and females, smokers and nonsmokers, and those who are physically active or not. Males, nonsmokers, and physically active individuals tend to have lower resting heart rates. Exercise 3: The ECG and Heart Sounds The average R-Lub interval (S1), the lub sound, lasts about 0.15 seconds. The average T-Dub interval (S2), the dub sound, lasts about 0.12 seconds. 1 Why does the lub sound occur around the peak of the R wave? The lub sound represents the closing of the atrioventricular (AV) valves, and is when ventricular pressure becomes greater than atrial pressure. This corresponds to ventricular contraction or systole. 2 Is the time delay between the R wave and the lub sound always the same? Why is this so? The time delay should be consistent between the R wave and lub sound because it corresponds to what is happening in the ECG cycle. 3 Why does the dub sound occur around the peak of the T wave? The dub sound is the second sound made by the heart and is when the semilunar valves snap closed at the beginning of ventricular relaxation or diastole. 4 Is the time delay between the T wave and the dub sound always the same? Why is this so? The time delay should be consistent between the R wave and lub sound because it corresponds to what is happening in the ECG cycle. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-7

12 Name Lab Section Exercise 1: The ECG in a Resting Subject Answer Sheet for Experiment HH-2: The Electrocardiogram and Heart Sounds 1 Is the amplitude of each wave (P, QRS, T) always the same in different cardiac cycles? 2 Which wave has the largest amplitude? 3 What is the average resting heart rate of the subject? Exercise 2: ECG Recordings from Other Subjects 1 Do the P waves of different subjects have the same amplitude? The QRS complexes? The T waves? Why? 2 For each subject, determine the wave with the largest amplitude. Is this result the same for all individuals? 3 Is the heart rate the same for each individual? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-8

13 4 What is the range of resting heart rates within the class? 5 Are there any obvious correlations between resting heart rate and gender, apparent fitness, or diet of your subjects? To determine apparent fitness, the class may want to compose a list of questions that will allow you to assign a relative fitness factor to each subject. Exercise 3: The ECG and Heart Sounds 1 Why does the lub sound occur around the peak of the R wave? 2 Is the time delay between the R wave and the lub sound always the same? Why is this so? 3 Why does the dub sound occur around the peak of the T wave? 4 Is the time delay between the T wave and the dub sound always the same? Why is this so? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-9

14 Experiment HH-3: Exercise, the Electrocardiogram, and Peripheral Circulation Exercise 1: The ECG and the Pulse in a Resting Subject There are no questions associated with this section. Exercise 2: The ECG and Pulse After Leg Exercises 1 How does the heart rate from the subject at rest and at 0, 30, 60, 90, and 120seconds after exercise (recovery) compare? If there is any variation between the rates for each time period, is there a trend and what is it? The heart rate in a subject at rest will be about the same as the heart rate at 120 seconds after exercise. Immediately after exercise, the heart rate should be considerably faster than at rest, slowing down to resting heart rate over a period of approximately 2 minutes. If the subject is physically fit, the heart rate will return to normal faster than in an unfit subject. 2 How does the average P-R interval from rest and each time period in recovery compare? Any variation or trend? The same holds true for each interval in the ECG. The time period between P-R will be shorter (making for a faster overall heart rate). This period will lengthen as recovery time progresses. 3 How does the average Q-T interval from rest and each time period in recovery compare? Any variation or trend? The Q-T interval will be shorter immediately after exercise, and lengthen as recovery time progresses. 4 How does the average T-P interval from rest and each time period in recovery compare? Any variation or trend? The T-P interval is when the heart is recovering to move on to the next beat cycle. This interval is shorter after exercise, and as the heart recovers and begins to beat at a slower rate, the T-P interval becomes longer. 5 How does the average R-Pulse interval from rest and each time period in recovery compare? Any variation or trend? The trend in the R-Pulse interval is the same trend as seen in the ECG intervals. Immediately after exercise the interval will be shorter (making for a faster heart rate) and over time, the interval lengthens, increasing heart rate back to that of the normal resting rate. 6 How does the average R-wave ECG amplitude from rest and each time period in recovery compare? Any variation or trend? The amplitude of the R wave may or may not increase in height. This will depend on the fitness of the individual, the age, gender and overall health of the heart. In some individuals, you may see an increase in amplitude, which will correspond to the heart working harder to pump blood to the exercising muscles. 7 How does the average pulse wave amplitude from rest and each time period in recovery compare? Any variation or trend? The pulse wave amplitude will also increase as the blood pressure increases to keep up with the demand of the exercising body. As the body returns to its resting state, the pulse amplitude will also return to normal. 8 Is there any affect on the blood flow through subject s finger as the subject is performing leg exercises? Yes, there will be a slight increase in the pulse amplitude, showing an increase in blood pressure as the muscles in the leg demand an increase in heart function. Exercise 3: The ECG and Pulse After Hand Exercises 1 How do the amplitudes of the pulse waves from the rest and each time period of recovery from hand exercise compare? Again, the amplitudes will be higher immediately after exercise and should decrease as the body comes back to rest. The waves may look more uneven (less of a smooth curve) due to more blood flowing through the hand during exercise. 2 How do the heart rates for rest and each time period of recovery from hand exercise compare? The heart rates should not be that much higher than normal while just exercising the hand muscles. When the entire body is recovering from exercise you will see a more dramatic change in the heart rate an ECG waves. 3 How do the amplitudes of the pulse waves from the leg and hand exercises compare? Does one type of exercise cause more blood flow in the hand than the other? The appearance of the pulse waves will not vary too much between the hand and leg exercises. The hand exercises increase the blood flow to the hand more quickly and recovery from this exercise is a bit faster, due to the fact that just the muscles of hand are Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-10

15 involved in increasing blood flow to that area. The leg exercises actually exercise the entire body (jogging in place or walking stairs will use the arms and the legs) and more pulse amplitude is needed for the blood to get to the leg muscles. Recovery from this exercise is slower than that of just the hand. 4 How do the heart rates from the leg and the hand exercise compare? Does one type of exercise cause a higher heart rate than the other? The leg exercises will cause a greater increase in heart rate and a slower recovery time compared to that of just exercising the hand muscles. 5 Do the R-pulse intervals and the R-wave amplitudes from the hand exercise differ from the same values from the leg exercise? Yes, these intervals and amplitudes will differ as stated previously. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-11

16 Name Lab Section Answer Sheet for Experiment HH-3: Exercise, the Electrocardiogram, and Peripheral Circulation Exercise 2: The ECG and Pulse After Leg Exercises 1 How does the heart rate from the subject at rest and at 0, 30, 60, 90, and 120seconds after exercise (recovery) compare? If there is any variation between the rates for each time period, is there a trend and what is it? 2 How does the average P-R interval from rest and each time period in recovery compare? Any variation or trend? 3 How does the average Q-T interval from rest and each time period in recovery compare? Any variation or trend? 4 How does the average T-P interval from rest and each time period in recovery compare? Any variation or trend? 5 How does the average R-Pulse interval from rest and each time period in recovery compare? Any variation or trend? 6 How does the average R-wave ECG amplitude from rest and each time period in recovery compare? Any variation or trend? 7 How does the average pulse wave amplitude from rest and each time period in recovery compare? Any variation or trend? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-12

17 8 Is there any affect on the blood flow through subject s finger as the subject is performing leg exercises? Exercise 3: The ECG and Pulse After Hand Exercises 1 How do the amplitudes of the pulse waves from the rest and each time period of recovery from hand exercise compare? 2 How do the heart rates for rest and each time period of recovery from hand exercise compare? 3 How do the amplitudes of the pulse waves from the leg and hand exercises compare? Does one type of exercise cause more blood flow in the hand than the other? 4 How do the heart rates from the leg and the hand exercise compare? Does one type of exercise cause a higher heart rate than the other? 5 Do the R-pulse intervals and the R-wave amplitudes from the hand exercise differ from the same values from the leg exercise? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-13

18 Experiment HH-4: The Six-Lead Electrocardiogram Background Information The heart axis can be calculated using just Lead I and avf. - If both Lead I and avf are positive = normal heart axis - If both Lead I and avf are negative = axis in Northwest Territory. Causes: lead transposition, emphysema, hyperkalemia - If Lead I is negative and avf is positive = right axis deviation Causes: normal in children and tall thin adults, right ventricular hypertrophy, atrial or ventricular septal defects - If Lead I is positive and avf is negative look at Lead II If Lead II is positive = normal heart axis If Lead II is negative = left axis deviation Causes: Q waves of inferior myocardial infarction, left anterior hemi-block, artificial cardiac pacing Exercise 1: A Six Lead ECG from a Resting Subject 1 From which leads were upright R waves recorded? From which electrode (left arm, right arm, left leg, or right leg) and along which axis (-150, -30, 0, 60, 90, 120 degrees) were these leads looking at the depolarization of the ventricle? In most ECG s (or EKG s), the positive, or upright, R waves are associated with Lead I (left arm) and the AVF Lead (left leg). These leads are positive as the signal travels from the sinoatrial (SA) node to the tip of the ventricles. The electrical signal in the heart travels from the top right to the bottom left 30 degrees above the X axis and 30 degrees to the left of the Y axis. 2 From which leads were inverted R waves recorded? From which electrode (left arm, right arm, left leg, or right leg) and along which axis (-150, -30, 0, 60, 90, 120 degrees) were these leads looking at the depolarization of the ventricle? Lead avr is usually the inverted lead. This lead is associated with the right arm at an axis of 150 degrees. 3 Which lead is the isoelectric lead? The isoelectric lead is the lead that is traveling at a 90 degree angle to any particular lead in the ECG trace. This lead, when added to its opposing lead, will create no deflection and is considered the isoelectric lead. Usually Lead II is the isoelectric lead. 4 What is the QRS axis of the subject s heart? Is the QRS axis of your subject within the normal range of the QRS axis? The QRS axis is related directly to the ECG of a particular subject and all individuals should have an axis that faces downward and to the left. Think of the shape and positioning of the heart in the thoracic cavity. The axis should face slightly towards the left arm. Lead II (the isoelectric lead) should be the direction of the QRS axis. 5 Which ECG lead provided the largest R wave for the subject? Lead II usually has the largest R waves. 6 Which lead is closest to the QRS axis of the heart? Lead II (the isoelectric lead) is the lead closest to the QRS axis of the heart. See above for background information. Exercise 2: Six Lead ECG from Other Subjects 1 Do the R waves from the same lead go in the same direction for all subjects? The P waves? The T waves? In healthy individuals and those with a QRS axis in the same quadrant should show waves consistent with one another. Most subjects should have P, R and T waves in the same direction on the same leads. 2 What would cause an ECG wave from the same lead to go in the opposite directions in a different subjects? Something as simple as having the limb leads positioned incorrectly could cause the wave to go in the opposite directions. Heart injury, disease or certain malformations of the heart could also cause this. 3 Do all subjects have the same QRS axis? What is the range of QRS axes from all the subjects in the class? Does the any subject have a QRS axis that is outside the normal range? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-14

19 As stated previously, most subjects will have the QRS axis facing the same general direction within the same quadrant of a standard XY axis. There will be slight variations and occasionally you will find someone with a heart angle outside the norm. 4 Does any subject have an inverted P or T wave on any lead when compared to the same lead from a normal ECG? It may be that you have a subject who has an inverted P or T wave. This can be caused by something as simple as drinking ice water. Age, race and anxiety levels can also cause these waves to be inverted. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-15

20 Name Lab Section Answer Sheet for Experiment HH-4: The Six-Lead Electrocardiogram Exercise 1: A Six Lead ECG from a Resting Subject Table IG-HH-4-1: The Mean Amplitudes (in millivolts) for Each ECG Wave Recorded from Each Lead. Lead I Lead II Lead III avr avl avf Mean Amplitudes (mv) P Wave R Wave T Wave 1 From which leads were upright R waves recorded? From which electrode (left arm, right arm, left leg, or right leg) and along which axis (-150, -30, 0, 60, 90, 120 degrees) were these leads looking at the depolarization of the ventricle? 2 From which leads were inverted R waves recorded? From which electrode (left arm, right arm, left leg, or right leg) and along which axis (-150, -30, 0, 60, 90, 120 degrees) were these leads looking at the depolarization of the ventricle? 3 Which lead is the isoelectric lead? 4 What is the QRS axis of the subject s heart? Is the QRS axis of your subject within the normal range of the QRS axis? 5 Which ECG lead provided the largest R wave for the subject? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-16

21 6 Which lead is closest to the QRS axis of the heart? Exercise 2: Six Lead ECG from Other Subjects 1 Do the R waves from the same lead go in the same direction for all subjects? The P waves? The T waves? 2 What would cause an ECG wave from the same lead to go in the opposite directions in a different subjects? 3 Do all subjects have the same QRS axis? What is the range of QRS axes from all the subjects in the class? Does the any subject have a QRS axis that is outside the normal range? 4 Does any subject have an inverted P or T wave on any lead when compared to the same lead from a normal ECG? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-17

22 Experiment HH-5: The Diving Reflex Exercise 1: Heart Rate at Rest There are no questions associated with this section. Exercise 2: Heart Rate and Apnea 1 How does the subject s average heart rate while resting compare to the heart rate while holding breath? You should see a decrease in overall heart rate while the subject is holding his/her breath. There may be an initial increase, but overall, the rate will decrease. 2 How do the subject s maximum and minimum heart rates while resting compare to the same heart rates while holding breath? The maximum heart rate at rest will be lower than the maximum while holding one s breath. The minimum heart rate at rest will be greater than that of the subject in apnea. Exercise 3: Heart Rate While Testing the Diving Reflex 1 What happens to the subject s heart rate as their face is submerged in the room temperature water? The subject s heart rate may drop, though not significantly. 2 What happens to the subject s heart rate as their face is submerged in the colder water? You should see a more dramatic drop in heart rate than that seen with room temperature water. 3 What causes the subject s heart rate to change when their face is submerged in cold water? How does the mammalian diving reflex help a person who falls into cold water? Think in terms of the organs that need oxygen. The cause of the drop in heart rate is due to vasoconstriction of the blood vessels as they are exposed to cold temperature. This increased pressure on the blood vessels actually raises blood pressure. In order for the individual to maintain normal blood pressure, the heart rate will slow down (bradycardia) to maintain the proper homeostatic balance. The mammalian diving reflex could help a person who has fallen into cold water by actually keeping blood flowing only to the parts of the body that really need it, i.e.: the brain. Vasoconstriction occurs in the peripheral blood vessels, shunting blood flow to the inner body core and vital organs. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-18

23 Name Lab Section Answer Sheet for Experiment HH-5: The Diving Reflex Exercise 2: Heart Rate and Apnea Table IG-HH-5-1: Heart Rate at Rest, during Apnea and Facial Exposure to Different Temperatures. Average Heart Rate (BPM) Treatment Max Min Mean Resting Holding Breath Face in 25 o C Water Face in 15 o C Water Face in 5 o C Water First 5 Last 5 First 5 Last 5 First 5 Last 5 1 How does the subject s average heart rate while resting compare to the heart rate while holding breath? 2 How do the subject s maximum and minimum heart rates while resting compare to the same heart rates while holding breath? Exercise 3: Heart Rate While Testing the Diving Reflex 1 What happens to the subject s heart rate as their face is submerged in the room temperature water? 2 What happens to the subject s heart rate as their face is submerged in the colder water? 3 What causes the subject s heart rate to change when their face is submerged in cold water? How does the mammalian diving reflex help a person who falls into cold water? Think in terms of the organs that need oxygen. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-19

24 Experiment HH-6: Heart Rate Variability (HRV) The more flexibility your heart rate exhibits between beats, known as heart rate variability (HRV), the healthier you are. HRV is the measure of change in the heart's beat-to-beat rate. The more monotonous, or constant the heart rate, the lower the HRV ratio. The well-known 1994 Framingham Heart Study, has previously identified HRV as the only common factor associated with all healthy individuals. Maintaining a certain degree of HRV is vital to overall health. Exercise 1: HRV in Resting Subject 1 Did the LP values of the subject at rest go down as his or her HP values went up? Yes, to keep the HRV ratio constant, you should see a decrease in LP as HP increases and visa versa. 2 How do the HRV ratios from the first through the fifth minute of the rest period compare? Is your subject more or less stressed as the rest period passes? It may be that you see a change in LP and HP values. If there is an increase in LP values and a decrease in HP values, to put the HRV ratio above 1.5, there is a good chance that your subject is stressed. 3 How do the resting HRV ratios of the subjects in your study group compare? To make a comparison use the HRV ratio from each subject s fifth minute in the rest period. See above answer. 4 How does the mean resting HRV ratio of the study group compare to the mean resting HRV ratios from other study groups? Again, use the ratio from the fifth minute in each rest period. If all the subjects are reacting the same way to being at rest, then the HRV ratios should be similar. Age, gender and physical fitness will play in role in HRV values. If the groups are homogeneous for certain characteristics (smokers vs. nonsmokers, males vs. females), you will see distinct differences in HRV ratios. 5 Which study group had the lowest resting HRV ratio? Low HRV values may be seen in subjects who are calm. Older individuals will have lower HRV ratios also. Vagal control shows low HRV values. 6 Which study group had the highest resting HRV ratio? High HRV values will be seen younger subjects, stressed individuals and smokers. 7 What can the study group with the highest resting HRV ratio do to reduce their HRV ratio? Subjects can use many different techniques to reduce their HRV ratio. Changing their daily activities to include no smoking, a healthy diet and exercise is important. Meditation to reduce stress and anxiety has been shown to lower HRV. Exercise 2: HRV After Exercise 1 How do the HRV ratios in the first through fifth minutes of recovery from exercise compare? Is your subject less stressed at the end of the recovery period? Immediate HRV ratios increase after exercise, and over time the ratio should decrease, resulting in a less stressed subject as different nerve centers are activated. 2 How does the HRV ratio from the fifth minute of the resting period compare to the HRV ratios from the first through the fifth minute of the recovery from exercise period? There will be variability between subjects, however the fifth minute resting period HRV ratio may be higher than that after the fifth minute of recovery. 3 How do the recovery HRV ratios of the subjects in your study group compare? To make a comparison use the HRV ratio from each subject s fifth minute in the recovery period. This will depend on your subjects. 4 How does the mean recovery HRV ratio of the study group compare to the mean recovery HRV ratios from other study groups? Again, use the ratio from the fifth minute in each recovery period. This will depend on your subjects. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-20

25 5 Which study group had the lowest recovery HRV ratio? This will depend on your subjects. 6 Which study group had the highest recovery HRV ratio? This will depend on your subjects. 7 What can the study group with the highest recovery HRV ratio do to reduce their HRV ratio? This will depend on your subjects. Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-21

26 Name Lab Section Answer Sheet for Experiment HH-6: Heart Rate Variability (HRV) Exercise 1: HRV in Resting Subject Table IG-HH-6-1: Heart Rate and HRV Values for Each Five Minute Task. Heart Rate (BPM) HRV LP HRV HP HRV Ratio Min Rest Post Exer Pre Test Test Post Test Rest Post Exer Pre Test Test Post Test Rest Post Exer Pre Test Test Post Test Rest Post Exer Pre Test Test Post Test 1st 2nd 3rd 4th 5th 1 Did the LP values of the subject at rest go down as his or her HP values went up? 2 How do the HRV ratios from the first through the fifth minute of the rest period compare? Is your subject more or less stressed as the rest period passes? 3 How do the resting HRV ratios of the subjects in your study group compare? To make a comparison use the HRV ratio from each subject s fifth minute in the rest period. 4 How does the mean resting HRV ratio of the study group compare to the mean resting HRV ratios from other study groups? Again, use the ratio from the fifth minute in each rest period. 5 Which study group had the lowest resting HRV ratio? 6 Which study group had the highest resting HRV ratio? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-22

27 7 What can the study group with the highest resting HRV ratio do to reduce their HRV ratio? Exercise 2: HRV After Exercise 1 How do the HRV ratios in the first through fifth minutes of recovery from exercise compare? Is your subject less stressed at the end of the recovery period? 2 How does the HRV ratio from the fifth minute of the resting period compare to the HRV ratios from the first through the fifth minute of the recovery from exercise period? 3 How do the recovery HRV ratios of the subjects in your study group compare? To make a comparison use the HRV ratio from each subject s fifth minute in the recovery period. 4 How does the mean recovery HRV ratio of the study group compare to the mean recovery HRV ratios from other study groups? Again, use the ratio from the fifth minute in each recovery period. 5 Which study group had the lowest recovery HRV ratio? 6 Which study group had the highest recovery HRV ratio? 7 What can the study group with the highest recovery HRV ratio do to reduce their HRV ratio? Instructor s Guide for Standard IPLMv4: Human Heart Chapter IG-HH-23

28 Human Circulation Chapter The ventricles contract to push blood into the arterial system and then relax to fill with blood before pumping once more. This intermittent ejection of blood into the arteries is balanced by a constant loss of blood from the arterial system through the capillaries. When the heart pushes blood into the arteries there is a sudden increase in pressure, which slowly declines until the heart contracts again. Thus, the pressure in the arteries varies during the cardiac cycle, being at its highest level immediately after the ventricle contracts (systolic pressure) and at its lowest level immediately prior to the pumping of blood into the arteries (diastolic pressure). These blood pressures are traditionally measured by a trained practitioner using a stethoscope and a sphygmomanometer (blood pressure cuff). The cuff is usually placed on the upper left arm and inflated to stop the flow of blood in the brachial artery into the lower arm when the cuff is high enough to cause the artery to collapse. When the pressure in the cuff is released and the systolic pressure in the artery is greater than the pressure in the cuff, blood flows through the partially collapsed artery with a thumping sound, known as a Korotkoff s sound. When cuff pressure decreases to the level equal to the diastolic pressure, the sound heard through the stethoscope becomes muffled and disappears. Normal adult blood pressure are around 120/80 mmhg (systolic/diastolic). Experiment HC-1: Blood Pressure, Peripheral Circulation, and Body Position Exercise 1: Blood Pressures from the Left Arm There are no questions associated with this section. Exercise 2: Repeatability of Blood Pressure Measurements 1 Are the systolic and diastolic blood pressures from Exercises 1 and 2 identical? What are the possible sources of variation? For the most part, the blood pressures should remain fairly constant after repeat trials. However, nervousness, excitability, stress, and other factors can cause changes in blood pressure. 2 Since the pressures are determined using changes in the pulse amplitude, would slowing the rate at which pressure is released from the cuff make your readings more accurate? It will make readings more accurate as you release the pressure in cuff more slowly. Too slow, however, will result in inaccurate readings as the blood will not flow with as much force to give you enough pressure to trigger the plethysmograph to read accurately. Too fast will also give inaccurate results. Exercise 3: Blood Pressures from the Right Arm Question Are the values the same as those obtained for the left arm? Explain any differences. The values from the right arm may be a little lower than those from the left arm due to distance from the heart. The farther away from the left ventricle the blood pressure is taken the lower it will be. It is important to note on medical charts where blood pressure was taken to take into account this fact. Exercise 4: Blood Pressures from the Forearm Question Are the values from the forearm the same as those obtained with the cuff on the upper arm? Explain any variations that you see. Values in the upper arm will tend to be higher than those in the forearm two main reasons. The first being the distance from the major artery (the brachial, in this case) and the second being the size of the blood vessels. Blood vessel size decreases from upper to forearm. Exercise 5: Blood Pressures with Different Arm Positions Question What is the effect of raising each hand on the blood pressure in the left arm? Explain your results. Raising the arm results in lower blood pressure. Gravity works against blood pressure. Think about holding your hand in the air for a while, the fingers begin to tingle as the blood flow to the area is decreased. Instructor s Guide for Standard IPLMv4: Human Circulation Chapter IG-HC-1

29 Exercise 6: Blood Pressures from the Leg 1 Are the blood pressure values from the leg the same as those obtained from the arms? Explain any differences. Blood pressure in the legs will be lower than that of the arm. Farther away from the left ventricle tends to give lower blood pressures. 2 What happens to the blood pressures in the subject s left leg when the subject reclines? When the subject lifts his or her left leg perpendicular to the bench? When the subject stands? After the subject has been standing for three minutes? Reclining closest to normal upper arm blood pressure Lifting Leg lower blood pressure, working against gravity Standing higher blood pressure than the reclining leg Three Minute Standing higher blood pressure than standing Instructor s Guide for Standard IPLMv4: Human Circulation Chapter IG-HC-2

30 Name Lab Section Answer Sheet for Experiment HC-1: Blood Pressure, Peripheral Circulation, and Body Position Exercise 1: Blood Pressures from the Left Arm Table IG-HC-1-1: Blood Pressures from Different Arms in Different Positions Subject Cuff Location/Hand Position Systolic Pressure (mmhg) Diastolic Pressure (mmhg) Pulse Pressure (mmhg) BP Class Upper Left Arm/Hand Low, Ex.1 Upper Left Arm/Hand Low, Ex.2 Upper Right Arm/Hand Low Lower Right Arm/Hand Low Left Arm/Left Hand Low Left Arm/Right Hand High Left Arm/Left Hand High Exercise 2: Repeatability of Blood Pressure Measurements 1 Are the systolic and diastolic blood pressures from Exercises 1 and 2 identical? What are the possible sources of variation? 2 Since the pressures are determined using changes in the pulse amplitude, would slowing the rate at which pressure is released from the cuff make your readings more accurate? Exercise 3: Blood Pressures from the Right Arm Question Are the values the same as those obtained for the left arm? Explain any differences. Instructor s Guide for Standard IPLMv4: Human Circulation Chapter IG-HC-3

31 Exercise 4: Blood Pressures from the Forearm Question Are the values from the forearm the same as those obtained with the cuff on the upper arm? Explain any variations that you see. Exercise 5: Blood Pressures with Different Arm Positions Question What is the effect of raising each hand on the blood pressure in the left arm? Explain your results. Exercise 6: Blood Pressures from the Leg Table IG-HC-1-2: Blood Pressures from the Left Leg in Different Positions Subject Leg Position Systolic Pressure (mmhg) Diastolic Pressure (mmhg) Pulse Pressure (mmhg) BP Class Sitting Reclining Leg Vertical Standing Standing 3 Mins 1 Are the blood pressure values from the leg the same as those obtained from the arms? Explain any differences. 2 What happens to the blood pressures in the subject s left leg when the subject reclines? When the subject lifts his or her left leg perpendicular to the bench? When the subject stands? After the subject has been standing for three minutes? Instructor s Guide for Standard IPLMv4: Human Circulation Chapter IG-HC-4

32 Experiment HC-2: Blood Pressure, Peripheral Circulation, and Imposed Conditions Exercise 1: Measuring Blood Pressures There are no questions associated with this section. Exercise 2: Effects of Food Additives The effect of food additives will be examined as a class project. Choices include: Caffeinated, regular soda Caffeinated, sugar-free soda Decaffeinated, regular soda Decaffeinated, sugar-free soda Water (control) Other possible studies could include the effects of eating foods with monosodium glutamate or drinking sports drinks with different levels of sugars and salts. 1 Are there any differences among your subject s blood pressures and heart rates at different time intervals? Yes, you will see differences over a longer period with regard to changes in blood pressure. You may see an increase in blood pressure in students consuming caffeine and sugar compared to no caffeine and no sugar. MSG and sports drinks will increase blood pressure as well. 2 Check the data from other subjects. Which treatment caused the greatest percentage change in the subject s blood pressure? Drinks with both caffeine and sugar should have increased blood pressure the most, caffeine alone will increase blood pressure more than a drink with no caffeine but with high sugar content. Decaffeinate, sugar sweetened drinks will increase blood pressure more than a sugar-free decaffeinated beverage. 3 Which treatment caused the greatest percentage change in the subject s heart rate? Corresponding increases in heart rate should also be shown (see Question # 2). Exercise 3: Effects of Exercise 1 Compare the blood pressures before and after exercise. Does exercise change blood pressure? Exercise shows an increase in blood pressure and heart rate. 2 Compare the heart rates before and after exercise. How long does it take your subject s heart rate to return to the resting level? How does your subject s recovery time compare to those of other subjects. Heart rate will be elevated immediately after exercise. Recovery time depends on many factors including overall physical fitness, health, gender, age, smoking, etc. Subjects with the same attributes should show similar recovery times. Exercise 4: Effects of Apnea 1 What effect does apnea have on the subject s blood pressure? Holding one s breath will show an initial increase in blood pressure and than an overall decrease in blood pressure as the amount of oxygen in the body decreases. 2 How does the subject s blood pressure change when the subject resumes breathing after apnea? Blood pressure elevates back to normal after the apnea episode is complete. Exercise 5: Effects of Cooling the Forearm 1 By examining the pulse data during the cooling period, determine if cooling has any effect on pulse amplitude? Explain your conclusion. Instructor s Guide for Standard IPLMv4: Human Circulation Chapter IG-HC-5