Brainscape's Knowledge GenomeTM

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


See full index

Histology > Unit 4 - The heart as a pump > Flashcards

Unit 4 - The heart as a pump Flashcards

1
Q

What is this diagram representative of?

A

The cardiac cycle

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

What interval is the atrial kick phase?

A

P-Q

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

What happens during the atrial kick phase?

A

S4 ‘atrial gallop’ sound, increase in left ventricular volume, increase in left atrial and left ventricular pressure, AP slowly decreasing

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

What is happing to the atrium during the atrial kick phase?

A

It is depolarizing and then begins contraction

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

Why is the atrial kick phase important?

A

because it gives the ventricle the final volume it needs before it contracts

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

Is the atrial kick phase during diastole or systole?

A

It is the end of diastole and the beginning of systole

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

What is occuring during the R peak of the QRS complex?

A

it is the beginning of the S1 sound, left ventricular volume is at peak, left arterial pressure is at peak, it is the moment right before the pressure in the left ventricle increases, and action potential is decreasing

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

What is the R-S interval also known as?

A

isovolumic contraction

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

What is happening across the heart during isovolumic contraction?

A

S1 sound, left ventroicular volume is steady, left atrial pressure decreases, left ventricular pressure increases dramatically, action potential is at the lowest

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

Why does left ventricular volume remain steady during isovolumic contraction?

A

Because the aortic valve is closed

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

What events are occuring to the left ventricle during isovolumic contraction?

A

the ventricle is depolarizing and then begins to contract

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

Is isovolumic contraction considered a systolic phase or diastolic?

A

systolic

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

What is the S-T interval also known as?

A

the ejection phase

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

What is happening during the ejection phase?

A

Left ventricular volume decreases, Left arterial pressure increases slightly, left ventricular pressure reaches its peak and slowly declines, action potential hits peak and then begins to decline

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

Physiologically, what is the ejection phase also known as?

A

physiological diastole

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

Why does left ventricular volume decrease during the ejection phase?

A

because the semilunar valves open and the stroke volume enters the arteries

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

What event happens at the end of the t-wave?

A

isovolumic relaxation

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

What happens during isovolumic relaxation?

A

S2 ‘dub’ sound, Left ventricular volume remains steady, Left atrial and left ventricular pressure increases to peak, action potential is back to repolarized state

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

What phase happens after the t-wave, but before the T-P interval?

A

rapid filling

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

What happens during the rapid filling phase?

A

S3 sound, left ventricular volume increases, left atrial and ventricular volume is low, action potential is decreasing

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

Why does left ventricular volume increase during the rapid filling phase?

A

The atrioventricular valves have opened allowing blood to rapidly fill into the ventricle

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

What phase happens during the T-P interval?

A

diastasis

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

What is happening during diastasis?

A

left ventricular volume is steady, left atrial pressure and left ventricular pressure remain steady and equal, action potential is decreasing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is cardiac output?

A

the volume of blood being pumped by the heart per unit time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How do you calculate cardiac output?

A

CO=SV x HR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How does increased heart rate affect cardiac output?

A

it increases it

27
Q

How does increased contractility affect cardiac output?

A

it increases stroke volume which increases cardiac output

28
Q

How does increased preload affect cardiac output?

A

it increases stroke volume, which increases ventricular filling which increases cardiac output

29
Q

How does increased afterload affect cardiac output?

A

it increases left ventricular pressure so the ventricle is not able to eject as much blood which decreases stroke volume therefore decreases cardiac output

30
Q

What are some methods for estimating contractility?

A

Ejection fraction, fractional shortening, dp/dt max

31
Q

What is the ejection fraction?

A

relates SV to SVE is an index of the extent of LV fiber shortening

32
Q

What is fractional shortening?

A

% change from diastolic to systolic left ventricle diameter

33
Q

How is fractional shortening obtained?

A

by echocardiography

34
Q

What is this?

A

A normal pressure volume loop for left ventricular pressure

35
Q

What is happening in phase 1 of this diagram?

A

the left ventricle is filling

36
Q

What is happening in phase 2 of this diagram?

A

the mitral valve closes, pressure rises in the left ventricle

37
Q

What is happening between phase 2 and phase 3?

A

isovolumic contraction

38
Q

What is happening in phase 3 of this diagram?

A

The aortic valve opens,

39
Q

What is happening in phase 4 of this diagram?

A

Peak pressure of the ventricle is reached

40
Q

What is happening between phase 4 and 5 of this diagram?

A

ejection from the ventricles

41
Q

What happens in phase 5 of this diagram?

A

the aortic valve closes, the end of the ejection phase, the beginning of ventricular relaxation

42
Q

What is happening between phase 5 and phase 6 of this diagram?

A

isovolumiv relaxation

43
Q

What happens at phase 6 of this diagram?

A

the mitral valve opens and the ventricle begins filling

44
Q

How does increased contractility affect the normal pressure loop?

A

the end systilic pressure shifts to a lower ventricular volume (to the left), peak pressure increases

45
Q

How does increased preload affect the normal pressure loop?

A

The ventricular phase is longer due to increased preload, contraction is the same, but peak pressure is higher

46
Q

How does increasing afterload affect the pressure volume loop?

A

ventricular pressure is higher, the period between phase 2 and 3 extends, the peak increases, the ejection phase is shorter because it will not get back to end systolic volume

47
Q

How is the law of LaPlace calculated?

A

Wall stress = (P x radius)/wall thickness

48
Q

The bigger the left ventricle, the ______ the all stress.

A

greater

49
Q

The greater the systolic pressure, the _______ the wall stress.

A

greater

50
Q

How does an increase in wall stress relate to O2 intake?

A

it increases

51
Q

What is eccentric hypertrophy?

A

chronic increase in volume load

52
Q

How does volume overload lead to eccentric hypertrophy?

A

volume overload leads to increased diastolic wall stress which leads to increased sarcomere in series

53
Q

What is concentric hypertrophy?

A

chronic increases in systolic pressure

54
Q

How does pressure overload lead to chronic hypertrophy?

A

pressure overload leads to increased systolic wall stress, which leads to increased sarcomeres in parallel which leads to CH

55
Q

What are the five determinants of ventricular filling?

A

Active relaxation of the myocardium, Ventricular compliance, Venous return, Duration of diastole, Atrial contraction

56
Q

How does active relaxation affect normal vetricular filling?

A

When the AV valves open, the ventricle is still actively relaxing causing it to aspirate some blood from the atrium

57
Q

How does reduced ventricular compliance affect diastolic function?

A

there is higher filling pressure which leads to smaller end diastolic volume

58
Q

What does ventricular compliance depend on?

A

Ventricular dimensions, Wall thickness, Muscle activity (active relaxation), Wall composition, External compression

59
Q

What is dp/dt max?

A

the slope of isovolumic contraction

60
Q

What does a steep slope of dp/dt max indicate?

A

higher contraction

61
Q

Where is the sympathetic innervation of the heart?

A

the entire heart

62
Q

What are the effects of sympathetic stimulation?

A

increase contractility, increases rate of relaxation by reducing rate of affinity for Ca for troponin and by accelerating uptake of Ca into SR by phosphorylating PL, increase heart rate, increase AV conduction

63
Q

Where does the parasympathetic system innervate?

A

SA and AV nodes

64
Q

What is the affect of parasympathetic innervation?

A

Heart rate decreases, AV conduction decreases, Contractility decreases

Histology (36 decks)

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