Cardio & Respiratory Wk 12 - Lesson 92

What is isovolumetric contraction?

period during ventricular systole when the ventricles contract with no volume change because all heart valves are closed

What is isovolumetric relaxation?

period during ventricular diastole when the ventricles relax with no volume change because all heart valves are closed

What is the end-diastole volume?

filled volume of the ventricle before contraction

What is end-systolic volume?

residual volume of blood remaining in the ventricle after ejection

What is preload?

degree of stretch of the cardiac muscle fibers at the end of diastole

What is afterload?

resistance the ventricles must overcome to eject blood during systole

What is phonocardiography?

recording of heart sounds and murmurs using a sensitive microphone and recording device

What guarantees blood flow through the heart?

pressure gradient

What kind of process is diastole?

passive process but still needs ATP

What phase has semilunar valves closed?

diastole

What phase has AV valves closed?

systole

What are the phases of the cardiac cycle during diastole?

5-2

What are the phases of the cardiac cycle during systole?

3-4

What is phase 5 of the cardiac cycle?

isovolumetric ventricular relaxation

What is phase 1 of the cardiac cycle?

ventricular filling

What is phase 2 of the cardiac cycle?

atrial contraction or atrial systole

What is phase 3 of the cardiac cycle?

isovolumetric ventricular contraction

What is phase 4 of the cardiac cyle?

ventricular ejection or systole

What phase is S2 associated with?

phase 5; associated with closure of the semilunar valves

What phase is S3 associated with?

ventricular filling

What phase is S4 associated with?

atrial contraction

What animal is it normal to hear the S3 and S4?

horses

What phase is associated with S1?

phase 3; associated with the AV valves closing

When does the pulse occur?

just after S1

What is the pressure-volume loop?

graph of left ventricular pressure against left ventricular volume to explore the intricacies of the heart's function

What is another term for left ventricular end-diastolic pressure (LVEDP)?

preload

What is another term for systemic vascular resistance (SVR)?

afterload

When is preload increased?

during hypervolemia and regurgitation of cardiac values

When is afterload increased?

during hypertension and vasoconstriction

What is the Frank-Starling Mechanism?

preload leads to stronger contraction and greater stroke volumes; ventricular filling is increased which stretches the fibers and troponin C becomes more sensitive to Ca leading to more force

What happens to cardiac output with increased preload?

increases cardiac output

3 multiple choice options

What happens to cardiac output with increased contractility?

increases cardiac output

3 multiple choice options

What causes decreased cardiac ouput?

increased afterload

3 multiple choice options

What generates heart sounds?

generated by the oscillation of blood and vibrations of muscles and valves

What are heart murmurs?

abnormal heart noises; generally S1 or S2

What causes heart murmurs?

altered valves, abnormal openings, anemia

Where do you listen for the mitral valve?

left side 5th intercostal space; S1 louder

Where do you listen for the aortic valve?

left 4th intercostal space dorsal to MV; S2 heard better

What valve can be heard from the left 3rd intercostal space at the sternal border?

pulmonic valve

What valve can be heart from the right 3rd and 4th intercostal space?

tricuspid valve

What are heart murmurs graded out of?

6

How are heart murmurs graded?

by their intensity

What is a 1/6 heart murmur?

nearly imperceptible; need careful auscultation with quiet environment; always focal

What is a 2/6 heart murmur?

heard readily but soft; always focal

What is a 3/6 heart murmur?

heard readily, moderate intensity; usually regional

What is a 4/6 heart murmur?

heard readily, loud, and usually radiates widely but without a palpable thrill

What is a 5/6 heart murmur?

heard readily, loud, and associated with a precordial thrill, but the murmur is not heard with the stethoscope lifted off the surface of the thorax

What is a 6/6 heart murmur?

heard readily, loud, associated with a precordial thrill, murmur remains audible with the stethoscope lifted 1 cm off the surface of the thorax

What is stenosis?

acquired or congenitally undersized valve or blood vessel; hear the murmur when the valve opens

What is insufficiency?

leakage of a valve during its closure; hear the murmur when the valves close

What valves will produce a stenosis murmur during systole?

semilunar valves

What valves will produce an insufficiency murmur during systole?

atrioventricular valves

What kind of murmur is it when it is heard while the atrioventricular valves are opening?

diastole stenosis

What kind of murmur is it when it is heard while the semilunar valves are closing?

diastole insufficiency

What part of the ECG occurs during a mitral valve insufficiency murmur?

begins during the QRS complex and ends during the T wave

What are the shunts in circulation during fetal development?

ductus arteriosus and foramen ovale

What causes blood to flow through the ductus arteriosus?

high pressure in collapsed lungs and low pressure in placenta causes a gradient for the blood to flow from pulmonary trunk to aorta

What is one of the most common congenital heart defects identified in dogs?

patent ductus arteriosus

How does the ductus arteriosus normally close?

at birth lung expansion occurs and there is higher oxygen tension which it is sensitive to; it contracts and the smooth muscle undergoes degeneration

What kind of murmur does the patent ductus arteriosus cause?

machinery/continuous murmurs during systolic and diastolic; has a combination of stenosis and insufficiency