cardiovascular physiology

Question 1

cardiac output equation

Answer 1

cardiac output = stroke volume x heart rate volume/min = (volume/beat) x (beats/min)

Question 2

how does positive chronotropic stimulus affect cardiac output

Answer 2

increase heart rate (sympathetic) which increases cardiac output

Question 3

how does postive inotropic stimulus affect cardiac output

Answer 3

increases stroke volume/contractility (sympathetic) which increases cardiac output

Question 4

how does arterial pressure affect cardiac output

Answer 4

when arterial pressure is high it increases the afterload which decreases the stroke volume thus decreasing cardiac output

Question 5

how does filling pressure affect cardiac output

Answer 5

when filling pressure is high (high preload) stroke volume increases (according to starlings law) and therefore cardiac output increases

Question 6

chronological list events contractions and valve events

Answer 6

atrial contraction –> mitral close –> tricuspid close –> ventricle contraction begins–> pulmonic valve open –> aortic valve open –> aortic valve close –> pulmonic valve close –> tricuspid open –> mitral valve open

Question 7

S1

Answer 7

atrioventricular valves closing “lub” sound immediately after QRS louder when: short PR, mild MVS, tachy softer when: AV block, mitral regurge, stiff LV

Question 8

S2

Answer 8

semilunar valves closing “dub” sound after T wave, start of relaxation intesity varies based on: pressure gradient, muscle stiffness, valve radius, and blood viscosity

Question 9

S3

Answer 9

result of ventricular overfilling: ventricular dilation and CHF SLOSH-ing-in (S1, S2, S3)

Question 10

S4

Answer 10

result of low compliance of ventricle: hypertension, ischemia, outlet obstruction a-STIFF-wall (S4, S1, S2)

Question 11

In a pressure volume loop like the one shown what does point 3 respresent

Answer 11

end diastolic pressure-volume relationship: indicates compliance

Question 12

on a pressure-volume loop like the one pictured what does number 7 represent

Answer 12

end systolic pressure-volume relationship: indicated contractility

Question 13

which number indicates the stroke volume

Answer 13

9 = stroke volume

Question 14

what is occuring during 8 on the pressure-volume loop

Answer 14

isovolumetric relaxation

valves closed

Question 15

what is happening during 4 on the loop

Answer 15

isovolumetric contraction

valves closed

Question 16

what numbers represent the aortic valve opening and closing

Answer 16

5: AV valve opens
7: AV valve closes

Question 17

what numbers on the loop indicate the mitral valve opening and closing

Answer 17

open: 1
close: 3

Question 18

what occurs during 2 on the loop

Answer 18

ventricular filling, diastole

Question 19

what occurs during 6 on the loop

Answer 19

ventricular emptying, systole

Question 20

What do numbers 1-4 represent on the cardiac cycle graph

Answer 20

1: stroke volume
2: systolic pressure
3: diastolic pressure
4: aortic pressure

Question 21

Status of the valves at each number 1-4

Answer 21

1: mitral valve close
2: Aortic valve opens
3. Aortic valve closes
4. Mitral valve opens

Question 22

Label each of the heart sounds and describe the sounds

Answer 22

1: S4: caused by stiffening ventricle, decreased compliance

Question 23

Atrial septal defect

symtpoms, physical exam findings, xray findings, echo findings

Answer 23

symptoms: slight murur, dyspnea on exertion, fatigue, frequent respiratory tract infections, tachycardia

physical exam findings: prominent systolic impulse palpatation, S2 widened with fixed split, systolic murmur upper-left sternal border: pulmonary valve, mid systolic murmur lower-left sternal border: tricuspid valve

xray: pruning of pulmonary vessels
echo: hypertrophy (the right ventricle chamber will be similar in size to left ventricle when it should be sibstantially larger)due to pulmonary hypertension

Question 24

list pressures within each chamber of the heart

Answer 24

right atria: 2-8

right ventricle: 15-30/2-8

pulmonary artery: 15-30/4-12

left atria and pulmonary capilary wedge: 2-10

left ventricle: 100-140/3-12

aorta: 100-140/60-90

Question 25

Frank-Starling law of the Heart

Answer 25

increases in fiber length will increase force of contraction/cardiac output as endiastolic fiber length, volume, and pressure increase so do cardiac output, stroke volume, and stroke work due to optimal sarcomere overlap and increased calcium sensitivity

Question 26

what is the red portion of the loop indicative of, explain changes in stroke volume and end diastolic pressure

Answer 26

decreased compliance (ventricular hypertrophy) stroke volume decreases end diastolic pressure increases

Question 27

what condition could the red pressure volume loop indicate how are stroke volume, end systolic volume, and end diastolic volume effected

Answer 27

mitral stenosis decreased stroke volume decreased end systolic volume (low afterload) decreased end diastolic volume (decresed LV filling)

Question 28

what does the shaded loop indicated how are stroke volume, end systolic volume, end diastolic volume effected

Answer 28

mitral stroke volume increased (increased compliance) \*however, ejection into the aorta is actually decreased, the ventricular stroke volume is including the blood exiting the ventricle to both the aorta and atria end systolic volume: decreases because takes both the blood entering the aorta and the atria into account end diastolic volume: increases because the increased volume in the atria due to regurge is then sent into the ventricles

Question 29

what could this pressure volume curve indicate explain changes in stroke volume end systolic volume and end diastolic volume and ventricular peak pressure

Answer 29

aortic regurgitation stroke volume increases end diastolic volume increases since blood backflows into ventricle end systolic volume increases since not all blood is able to escape the ventricle ventricular peak pressure increases because frank starling law, increased volume and stretching causes stronger contraction

Question 30

Explain what could cause this tall T wave

Answer 30

in mitral regurgitation, backflow into the atria occurs during ventricular contraction causing an increase in pressure

Question 31

what does PR interval indicate

Answer 31

time for action potential to conduct through AV node

Question 32

what does P wave indicate

Answer 32

duration of atrial depolarization

Question 33

what does the T wave indicate

Answer 33

ventricular depolarization

Question 34

what does QT interval indicate

Answer 34

how long ventricles remain depolarized

Question 35

what does QRS indicate

Answer 35

time for ventricular depolarization

Question 36

TP interval

Answer 36

heart at rest and ventricles are filling