Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cardiovascular > Mechanical events of the cardiac cycle > Flashcards

Mechanical events of the cardiac cycle Flashcards

1
Q

cardiac cycle

A

recurring atrial and ventricular contractions and relaxations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

systole

A

ventricular contraction and blood ejection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

diastole

A

alternating period of ventricular relaxation and blood filling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how long does the cardiac cycle last?

A

for typical rate of 72 beats/min

0.8 sec - 0.3 in systole and 0.5 in diastole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

2 parts of systole

A

isovolumetric ventricular contraction

ventricular ejection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

isovolumetric ventricular contraction

A

ventricles are contracting but all valves in the heart are closed, so no blood is ejected. atria are relaxed

ventricular walls are developing tension and squeezing on blood, increasing ventricular blood pressure

ventricular muscle fibres can’t shorten because volume of blood is constant and blood is incompressible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

ventricular ejection

A

increasing pressure in the ventricles exceeds pressure in the aorta and pulmonary trunk - aortic and pulmonary valves open. blood is forced into the aorta and pulmonary trunk.
ventricular muscle fibres shorten
atria are relaxed and AV valves are closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the stroke volume?

A

volume of blood ejected from each ventricle during systole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

parts of diastole

A

isovolumetric ventricular relaxation

ventricular filling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

isovolumetric ventricular relaxation

A

ventricles begin to relax and aortic and pulmonary valves close
AV valves are closed, no blood is entering or leaving the ventricles
atria are relaxed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

ventricular filling

A

AV valves open, blood flows in from the atria
after most of ventricular filling, the atria contract
approx. 80% of ventricular filling occurs before atrial contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

mid-diastole to late diastole: 1

A

left atrium and ventricle are both relaxed

atrial pressure slightly higher than ventricular pressure because it’s filled with blood entering from the veins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

mid-diastole to late diastole: 2

A

AV valve held open by the pressure difference, and blood entering the atrium from the pulmonary veins continues into the ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

mid-diastole to late diastole: 3

A

aortic valve is closed because aortic pressure is higher than the ventricular pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

mid-diastole to late diastole: 4

A

throughout diastole, pressure in the aorta is slowly decreasing because blood is moving out of the arteries and through the vascular system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

mid-diastole to late diastole: 5

A

ventricular pressure is increasing slightly due to blood entering relaxed ventricle from the atrium and expanding ventricular volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

mid-diastole to late diastole: 6

A

near the end of diastole, the SA node discharges and the atria depolarise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

mid-diastole to late diastole: 7

A

contraction of the atrium increases atrial pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

mid-diastole to late diastole: 8

A

elevated atrial pressure forces a small additional volume of blood into the ventricle (atrial kick)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

mid-diastole to late diastole: 9

A

end of ventricular diastole

amount of blood in ventricle is the end-diastolic volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

systole: 10

A

from the AV node, the wave of depolarisation passes into and throughout ventricular tissue, triggering contraction (QRS complex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

systole: 11

A

as ventricle contracts, the ventricular pressure increases immediately, exceeding the atrial pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

systole: 12

A

change in pressure gradient forces AV valve to close, preventing blood from flowing back into the atria

24
Q

systole: 13

A

aortic pressure still exceeds ventricular pressure, so the aortic valve is closed.
isovolumetric ventricular contraction
backward bulging of the AV valves causes a small upward deflection in the atrial pressure wave

25
Q

systole: 14

A

rapidly increasing ventricular pressure exceeds aortic pressure

26
Q

systole: 15

A

pressure gradient forces aortic valve to open, and ventricular ejection begins

27
Q

systole: 16

A

ejection is rapid at first, then slows down

28
Q

systole: 17

A

amount of blood remaining in ventricle after ejection is the end systolic volume

29
Q

stroke volume and typical values

A

edv - esv
sv = 70 mL
edv = 135 mL
esv = 65 mL

30
Q

systole: 18

A

aortic pressure increases with the ventricular pressure as blood flows into the aorta
very small pressure changes exist between the ventricles and aorta due to the aortic valve having little resistance to flow

31
Q

systole: 19

A

peak ventricular and aortic pressures are reached before the end of ventricular ejection
start to decrease in last part despite continued contraction

32
Q

systole: 20

A

force reduction evidenced by reduced rate of blood ejection in last part of systole

33
Q

systole: 21

A

volume and pressure in the aorta decreases as the rate of blood ejection from the ventricles becomes slower than the rate at which blood drains from arteries into tissues

34
Q

early diastole: 23

A

ventricles relax. ventricular pressure decreases below aortic pressure (elevated due to blood having entered). change in pressure gradient forces aortic valve to close.
AV valves also closed due to ventricles having higher pressure than atria

35
Q

what is the dichrotic notch

A

combination of elastic recoil of the aorta and blood rebounding against the valve causes a rebound of aortic pressure

36
Q

early diastole: 24

A

isovolumetric ventricular relaxation. ends when rapidly decreasing ventricular pressure decreases below atrial pressure

37
Q

early diastole: 25

A

change in pressure gradient causes AV valve to open

38
Q

early diastole: 26

A

venous blood that accumulated in the atria since the AV valve closed flows into the ventricles

39
Q

how is the rate of blood flow enhanced in early filling?

A

rapid decrease in ventricular pressure

40
Q

what is the rapid decrease in ventricular pressure caused by?

A

previous contraction compressed elastic elements of the chamber so ventricle tends to recoil outward after systole
may create subatmospheric pressure
some energy is stored within the myocardium during contraction, and its release in relaxation aids filling

41
Q

importance of filling occurring in early diastole

A

ensures filling is not impaired when heart beats very rapidly - total filling time reduced

42
Q

early filling and conduction defects

A

conduction defects eliminating atria as effective pumps don’t seriously impair ventricular filling

43
Q

atrial fibrillation

A

cells of atria contract in uncoordinated manner, so atria don’t work as effective pumps

44
Q

pressure changes in pulmonary circulation

A

qualitatively similar

quantitative differences

45
Q

systemic arterial pressures vs pulmonary arterial pressures

A

systemic arterial systolic (120mmHg) and diastolic (80mmHg)

pulmonary arterial systolic (25mmHg) and diastolic (10mmHg)

46
Q

how are heart sounds heard?

A

stethoscope placed on chest wall

47
Q

first and second sounds and their associations

A

1st: soft, low-pitched lub - closure of AV valves
2nd: louder dup - closure of pulmonary and aortic valves

lub is onset of systole
dup is onset of diastole

48
Q

what do heart sounds result from?

A

vibrations caused by the closing valves

49
Q

heart murmurs

A

sounds other than 2 normal heart sounds

50
Q

what can heart murmurs be caused by?

A

heart defects causing blood flow to be turbulent

51
Q

laminar flow

A

blood flows in smooth concentric layers

52
Q

turbulent flow causes

A

stenosis
insufficiency
septal defect

53
Q

what is stenosis?

A

blood flowing in usual direction through an abnormally narrowed valve

54
Q

what is insufficiency?

A

blood flowing backwards through a damaged, leaky valve

55
Q

what is a septal defect?

A

blood flowing between 2 atria or 2 ventricles through a small hole in the wall separating them

56
Q

murmur heard throughout systole

A

suggests stenotic pulmonary or aortic valve, insufficient AV valve or hole in interventricular septum

57
Q

murmur heard throughout diastole

A

stenotic AV valve or insufficient pulmonary or aortic valve

Cardiovascular (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions