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Flashcards in Cardiovascular Physiology Lab Deck (46):

Auscultation of the hearts means

to listen to and study the various sounds arising from the heart during its pumping activity


The vibrations producing the sounds can be visually displayed through the use of a heart sound microphone and physiological recorder to produce a



1st Heart Sound

Produced at the beginning of systole when the atrioventricular (AV) valves close and the semilunar (SL) valves open. This has a lower pitched tone commonly termed the "lub" sound of the heartbeat


2nd Heart Sound

Occurs during the end of systole and is produced by the closure of the SL valves, the opening of the AV valves, and the resulting vibrations in the arteries and ventricles. Due to the higher blood pressures in the arteries the sound produced is higher pitched. It is commonly referred to as the "dub" sound


3rd Heart Sound

Occurs during the rapid filling of the ventricles after the AV valves open and is probably produced by vibrations of the ventricular walls


4th Heart Sound

Occurs at the time of atrial contraction and is probably due to the accelerated rush of blood into the ventricles


The 4 Major Auscultatory Areas

Aortic Area (aortic SL valve)
Tricuspid Area (right AV valve)
Pulmonary Area (pulmonary SL valve)
Mitral Area (left AV valve)


Blood Pressure

the pressure exerted by the blood against the vessel walls


Where do we most commonly measure blood pressure?

arterial blood pressure


Systolic Blood Pressure

the highest pressure in the artery--produced during the heart's contraction (systolic) phase


Normal systolic blood pressure for a 20-year old male is

120mm Hg


Diastolic Blood Pressure

the lowest pressure in the artery--produced during the heart's relaxation (diastolic) phase


Normal diastolic blood pressure for a 20-year old male is

80mm Hg


Pulse Pressure

the difference between the systolic and diastolic pressures


Normal value for pulse pressure is

40mm Hg


Mean Blood Pressure

Diastolic Pressure + 1/3 of the pulse pressure. This is the average effective pressure forcing blood through the circulatory system


Normal value for mean blood pressure is

96-100mm Hg


Formula for Mean BP (mm Hg)

Cardiac Output (ml/min) X Total Peripheral Resistance (TPR units)


Formula for Cardiac Output

Cardiac Output (ml/min) = Heart Rate (beats/min) X Stroke Volume (ml/beat)


Peripheral Resistance depends on

the diameter of the blood vessels and the viscosity of the blood


In general we say that the systolic BP indicates ______ and the diastolic BP reflects _______

systolic = the force of contraction of the heart

diastolic = the condition of the systemic blood vessels
ex: an increase in the diastolic pressure indicates a decrease in vessel elasticity


Direct Method of measuring blood pressure

a cannula is inserted into the artery and the direct, head-on pressure of the blood is measured with a transducer or mercury manometer


Indirect Method of measuring blood pressure

pressure is applied externally to the artery and the pressure is determined by listening to arterial sounds (using a stethoscope) below the point where the pressure is applied
This is called the auscultatory method since the detection of the sounds is termed "auscultation"


Palpatory Method

Older and less accurate method. One simply palpates or feels the pulse as pressure is applied to the artery. You inflate the cuff, note when the pulse is first lost, go a little bit higher and then let air out as you wait for the first pulse which is the systolic blood pressure. The systolic blood pressure recorded with the palpatory method is usually around 5mm Hg lower than that obtained using the auscultatory method. Major disadvantage of this method is that it cannot be used to measure the diastolic pressure


In both indirect methods for blood pressure the instrument we use is

pressure is applied to the artery using an instrument called the sphygmomanometer; consists of an inflatable rubber bag (cuff), a rubber bulb, and a mercury or anaeroid manometer for measuring the pressure


Where is human blood pressure most commonly measured?

in the brachial artery of the upper arm; has the advantage of being approximately the same level as the heart so that the pressures obtained closely approximate the pressure in the aorta leaving the heart. Allowing us to correlate BP with heart activity


Auscultatory Method

pressure cuff is used and stethoscope is used to listen to the changes in sounds from the brachial artery. With no air in the cuff no sounds can be heard. Inflate the cuff beyond systolic pressure so that the artery is completely collapsed and no sounds are heard. Now open the valve and begin to slowly lower the pressure in the cuff


The Korotkow Sounds

Phase 1: Appearance of a fairly sharp thudding sound which increases in intensity during the next 10 mm Hg of pressure drop. The pressure when the sound first appears is the systolic pressure
Phase 2: The sounds become a softer murmur during the next 10-15 mm Hg drop in pressure
Phase 3: The sounds become louder again and have a sharper thudding quality during the next 10-15 mm Hg of pressure drop
Phase 4: The sounds suddenly become muffled and reduced in intensity. The pressure at this point is termed the diastolic pressure. Thus muffled sound continues for another 5 mm Hg pressure drop, after which all sound disappears. The point where the sound ceases completely is called the end diastolic pressure. It is sometimes recorded along with the systolic and diastolic pressures in this manner: 120/80/75


The auscultatory method is usually how far off from the direct method in the pressures recorded?

about 3-4 mm lower than that obtained with the direct method


Difference in BP between Men and Women

Below the age of 35, women generally have a BP 10 mm Hg lower than that for men. However, after 40-45 years of age, a woman's BP increases faster than does a man's


Rule of thumb for what your systolic pressure should be

100 plus your age; rule is valid until after the age of 50


Why does BP increase with age

The increase in BP with age is caused largely by the overall loss of vessel elasticity with age, part of which is due to the increased deposit of cholesterol and other lipid materials in the blood vessel walls


When you go from lying down to standing BP should

You may have an initial drop in blood pressure as blood pools but it should increase after your baroreceptors sense it and increase your heart rate


What generally happens to BP during exercise?

During aerobic exercise you should see an increase in BP as your heart rate is increased thereby raising the systolic pressure while keeping diastolic relatively the same
during vigorous exercise you can see a slight drop in BP, then it'll return to normal after rest


A crude estimate of peripheral resistance equation

TPR = mean arterial pressure / cardiac output

where cardiac output = stroke volume X heart rate

TPRest = [(systolic + 2 diastolic)/3] / [pulse pressure X heart rate]


A normal reflex response in BP to a cold stimulus is

an increase in blood pressure (both systolic and diastolic); In a normal individual the systolic pressure will rise no more than 10 mm Hg, but the rise in a hypertensive individual may be 30 to 40 mm Hg


Explain the test we did when the subject raised their hand and we measured the hand's height from the heart

lower the arm and observe the filling of the veins on the back of the hand, raise the hand and watch to the point where the veins are just barely collapsed; measure the distance in mm; this will give the atrial pressure in mm of blood. The specific gravity of blood is 1.056 while that of mercury is 13.6. Convert to mm of mercury by dividing by 13.6 and compare with arterial pressure at the level of the heart


What happens when we dunk our faces in icy cold water?

Mammallian dive reflex happens in 3 stages:
1. Bradycardia-is the first response to submersion. Immediately upon facial contact with cold water, the human heart rate slows down 10-25% percent. Slowing the heart rate lessens the need for bloodstream oxygen, leaving more to be used by other organs.
2. Peripheral vasoconstriction
3. Blood Shift
In humans, the mammalian diving reflex is not induced when limbs are introduced to cold water. Mild bradycardia is caused by subjects holding their breath without submerging the face within water.[4] When breathing with face submerged this causes a diving reflex which increases proportionally to decreasing water temperature


Why are children more likely to survive drowning in icy cold waters than adults?

Children have a survival advantage over adults in cold water. Their bodies have a higher surface area-to-volume ratio than adult bodies, so they cool more quickly—the same way that a cupcake just out of the oven cools faster than a sheet cake. They also have the innate ability to absorb more oxygen into their bloodstream than adults do, so, when they go underwater, there is already more oxygen available.


This test consists of measuring the endurance in stepping up and down a bench 20 inches high (16 for women) and the pulse reaction to this exercise. Measures general endurance.

Harvard Step Test


Harvard Step Test

This test consists of measuring the endurance in stepping up and down a bench 20 inches high (16 for women) and the pulse reaction to this exercise. Measures general endurance.


Harvard Step Test Index Formula

Index = Duration of exercise in seconds X 100 / 2 X (sum of the 3 pulse counts in recovery)

Below 55 = poor
55-64 = low avg
65-79 = high avg
80-90 = good
above 90 = excellent


Tuttle Pulse-Ratio Test

This test is based on the observation that for the same number of steps, a less fit person will have a relatively higher pulse rate during the 2-minute period of recovery immediately after exercise. Tuttle's pulse ratio is defined as the total number of pulse beats counted for one minute. The cardiovascular efficiency of a person is determined by the amount of exercise require to obtain a 2.5 pulse ratio. This test appears to be fairly accurate for measuring physical condition in the middle range and has also been found to be useful in the detection of pathological hearts and heart abnormalities


Steps to the Tuttle Pulse-Ratio Test

Subject sits at a chair until pulse is stabilized. Pulse is recorded over 1 minute
Subject makes 20 complete steps (up and down) in 1 minute on a bench 13 inches high (15 steps for females). Record the number of steps completed
Immediately after exercise, the subject sits, and the pulse is counted for 2 minutes
The total pulse for 2 minutes is divided by the resting rate. This is called the first "pulse ratio"
Subject rests until the pulse returns to normal
Subject steps up and down again for 1 minute, making 40 complete steps (35 for women). Record the number of steps
Immediately after exercise, subject sits, pulse is counted again for 2 minutes
The pulse obtained in 2 minutes is divided by the resting pulse. This is called the second "pulse ratio"
Then calculate the number of steps required to obtain a 2.5 pulse-ratio


Formula to record a 2.5 pulse-ratio

S0 = S1 + (S2-S1)(2.5-r1)/(r2-r1)

S1 = the number of steps used in the first test
S2 = the number of steps used in the 2nd test
S0 = the number of steps required to obtain a 2.5 ratio
r1 = the pulse ratio for S1
r2 = the pulse ratio for S2


The established norms for the Tuttle pulse-ratio test are:

boys, ages 10 to 12 years - 33 steps
boys, ages 13 to 18 years - 30 steps
adult man - 29 steps
adult women - 25 steps