cardiac cycle

Question 1

what is the blood pressure in vessels with no flow

Answer 1

7 mmHg

Question 2

how is the heart orientated

Answer 2

right side is mostly anterior

Question 3

what are the 5 stages of the cardiac cycle

Answer 3

1. atrial systole
2. isovolumetric contraction
3. ventricular ejection
4. isovolumetric relaxation
5. ventricular filling

Question 4

what does the;
P
QRS
T
waves stand for in ECG

Answer 4

• p is atrial depolarisation followed by contraction
• QRS is ventricle depolarisation followed by contraction
  -T is ventricle repolarisation- isovolumetric relaxation of cardiac cycle

Question 5

wiggers diagram what side of the heart does it measure

Answer 5

left

Question 6

during what stages of the cardiac cycle are all valves closed

Answer 6

• isovolumetric contraction
• isovolumetric relaxation

Question 7

during what stage of the cardiac cycle is ventricular volume the highest

Answer 7

• very end of atrial systole/ isovolumetric contraction

Question 8

during what stage of the cardiac cycle is the ventricular volume the lowest

Answer 8

• very end of ventricular ejection
• isovolumetric relaxation

Question 9

during what stage is ventricle pressure the highest

Answer 9

• middle of ventricular ejection

Question 10

when does av valves open

Answer 10

when atrial pressure is greater than ventricular pressure

Question 11

when does semi lunar valves open

Answer 11

• when ventricular pressure is greater than aortic pressure

Question 12

when do av valves close

Answer 12

when ventricular pressure greater than atrial pressure

Question 13

when do semi lunar vlaves close

Answer 13

when aortic pressure> ventricular pressure

Question 14

what is the diastollic pressure

Answer 14

• lowest pressure - when heart relaxes

Question 15

what is sytollic pressure

Answer 15

• pressure generated by left ventricle, so when its contracting

Question 16

what is mean arteriole pressure

Answer 16

MAP= 1/3(SP-DP)+DP

Question 17

what is stroke volume

Answer 17

change in volume of the ventricle when its contracting and ejecting blood out int the aorta during ventricular ejection in one cardiac cycle

Question 18

stroke volume equation

Answer 18

end diastolic volume- end systolic volume

Question 19

what increases cardiac output

Answer 19

increased heart rate

Question 20

what is pre load

Answer 20

the amount of blood than enters the left ventricle

Question 21

what affects stroke volume

Answer 21

• increased pre load= increase stroke volume
• increased contractility= increased stroke volume
• increased after load decreases stroke volume

Question 22

why does an increased pre load increases stroke volume

Answer 22

• increased pre load means the ventricles are more stretched
• this causes the cardiac muscle fibres to lengthen and this consequently increases stroke volume and the amount of blood that is ejected

Question 23

why does an increased after load decreases stroke volume

Answer 23

• increased after load means the heart has to build up more pressure to eject blood out and therefore work harder resulting in a lower stroke volume

Question 24

what is the starling law

Answer 24

• increased pre load results in ventricle stretch which leads to cardiac muscle fibres to lengthen and therefore this increases stroke volume
• graph is stroke volume against pre load and has a plaeteau shape graph where at high preloads stroke volume does not increase

Question 25

what is the lub dub sound that we can heart when listening to the heart

Answer 25

• first sound is lub and is the closing of the av
• second sound is dub and is the closing of the semi lunar valves

Question 26

what are the two valvular pathology

Answer 26

• stenosis
• regurgitation

Question 27

what is stenosis and what impact does it have on the wiggers diagram

Answer 27

• stenosis= valves cannot open
• aortic stenosis, semi lunar valve does not open and therefroe on the wiggle diagram theres a massive increase in ventricular pressure (greater pressure gradient between left ventricle and aortic pressure), also murmers in systole
• mitral stenosis- increased atrial pressure, ,murmers in diastole

Question 28

what is regurgitation and what impact does it have on wiggers diagram

Answer 28

• regurgitation valves do not close properly
• aortic regurgitation results in decreased diastolic aortic pressure as blood flows back into the lf- murmers in diastole
• mitral regurgiation- increase in left atrial pressure as blood flows back into left atrial from ventricle during systole- so murmer during systole