Cardiac cycle

Question 1

Illustrate the sequence of changes in pressure and volume in the chambers of the heart throughout the cardiac cycle.

Answer 1

1. late diastole- both sets of chambers are relaxed and ventricles fill passively.
2. atrial systole- atrial contraction forces a small amount of additional blood into ventricles
3. isovolumetric ventricular contraction- ventricle contraction pushes AV valves closed but doesnt creat enough pressure to open semilunar valves
4. ventricular ejection- as ventricular pressure rises and exceeds pressure in arteries the semilunar valves open and blood is ejected.
5. isovolumetric ventricular relaxation- ventricles relax, pressure falls. blood falls back into cusps of semilunar valves and snaps them closed and cycle repeats

Question 2

Interpret a pressure-volume loop.

Question 3

Explain the generation of the heart sounds (phonocardiogram).

Question 4

what is the diastole phase

Answer 4

filling of atrium or ventricles

Question 5

what is the systole phase

Answer 5

ejection phase of atrium or ventricles

Question 6

what is the a wave

Answer 6

atrial contraction

Question 7

what is the c wave

Answer 7

when mistrial valve closes and because its quite flappy it will budge into the left atrium increasing pressure

Question 8

what is the V wave

Answer 8

blood returning from lungs into the left atrium which has a low volume so when blood flows in pressure gradually increases and increases

Question 9

what is pulse pressure

Answer 9

difference between diastolic and systolic of the aorta

Question 10

what is mean arterial pressure

Answer 10

is a third of the way between diastolic and systolic

Question 11

what is the dicrotic notch

Answer 11

It is universally used to demarcate the end of systole and the beginning of diastole in these arteries. Due to the elastic properties of the aorta it decreases slowly

Question 12

what is it called between the distance of end systolic volume to end of diastolic volume

Answer 12

stroke volume however mainly is affected by size of the person

Question 13

what is the ejection fraction

Answer 13

stroke volume divided by the end diastolic volume which is a percentage of the blood in the ventricle pumped out with each contraction. in an unhealthy person this would be below 60%

Question 14

describe isometric contraction phase

Answer 14

mitral and aortic values are closed

Question 15

describe rapid ejection phase

Answer 15

pressure in left ventricle exceeds pressure on the aorta and pushes aortic value open and blood is pumped out of left ventricle quickly so volume is decreased rapidly

Question 16

isometric relaxation phase

Answer 16

mistrial and aortic values closed again

Question 17

rapid filling phase

Answer 17

pressure in left atrium exceeds left ventricle causing mitral value to open and blood is pushed from left atrium to left ventricle quickly.

Question 18

what side of the heart has a higher pressure

Answer 18

right side is only 1/5 of the left as only pumping into pulmonary circulation

Question 19

describe the phonocardiogram

Answer 19

1. closure of the AV valves
2. closure of the semi-lunar valves
3. rapid passive filling phase
4. active filling phase

heart sounds are caused by turbulence of blood flow. All heart valves are passive and open and close due to changes of pressure in the heart

Question 20

describe a systolic murmur

Answer 20

stenosis or narrowing of the aortic or pulmonary valves causing turbulence or regurgitation of blood through mitral or tricuspid valves (LUB SHHH DUB)

Question 21

describe a diastolic murmur

Answer 21

stenos of mitral and tricuspid valves or regurgitation from the aortic or pulmonary valves (LUB DUB SHH)

Question 22

normla phonocardiogram

Answer 22

lub systole dub diastole

Question 23

continuous murmur

Answer 23

Begins in the systole and is continuous. Could be patent ductus arteriosus.