12 - Heart Flashcards Preview

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Flashcards in 12 - Heart Deck (83):
1

The heart is responsible for pumping blood through two different systems of circulation. Which?

1. Pulmonary circulation
2. Systemic circulation.

2

The heart is located in which major body cavity?

Thoracic cavity.

3

The heart is located within which pleural cavity?

Neither. It's between the two.

4

The heart actually lies in its own minor cavity. Which?

Pericardial cavity.

5

The pericardial cavity is formed by ...

the pericardium.

6

What is the pericardium?

The pericardium is the tissues that surround the heart and anchor it within the mediastinum.

7

The heart is a muscular pump consisting of four chamber. Which?

The right and left atria. The right and left ventricles.

8

Which chamber(s) receive blood from veins?

The atria, both right and left.

9

The right atrium receives blood from..

from three major openings:
1. The superior vena cava
2. The inferior vena cava
3. The coronary sinus

10

The superior vena cava brings blood from ... to....

The superior vena cava drain blood from most of the body and empties out in the right atrium.

11

The inferior vena cava brings blood from .... to...

The inferior vena cava drain blood from most of the body and empties out in the right atrium.

12

The coronary sinus drains blood from .... to...

The coronary sinus drains blood from most of the heart muscle, and empties out in the right atrium.

13

Which veins empty into the left atrium?

The left atrium receives blood through the four pulmonary veins, which drain blood from the lungs.

14

What separates the two atria?

The two atria are separated from each other by a partition called the interatrial septum.

15

The right ventricle pumps blood to ...

the pulmonary truck.

16

The left ventricle pumps blood to ...

the aorta.

17

What separates the ventricles?

The interventricular septum.

18

Which ventricle is able to create the highest pressure?

The left.

19

What are the valves between the atria and the ventricles called?

The atrioventricular (AV) valves are located between the right atrium and the right ventricle and between the left atrium and the left ventricle.

20

Are there differences between the left and right atrioventricular valves?

Yes. The AV valve between the left atrium and the left ventricle is called the bicuspid, or mitral, valve. The AV valve between the right atrium and the right ventricle is called the tricuspid valve.

21

What is the difference between the bicuspid and tricuspid valves?

The tricuspid has three cusps, and the bicuspid has two.

22

What is the function of the valves?

They can close, preventing blood flow. When open, they prevent blood in the ventricles from flowing back into the atria.

23

Are there more valves than the bicuspid and tricuspid valves?

Yes. The aorta and pulmonary trunk possess aortic and pulmonary semilunar valves, respectively.

24

Blood in the left atrium is oxygen-rich or oxygen-poor?

Rich!

25

Blood in the right atrium is oxygen-rich or oxygen-poor?

Poor!

26

Explain the opening and closing of valves in contact with the right ventricle.

Following right atrial contraction, the right ventricle begins to contract. This contraction pushes blood against the tricuspid valve, forcing it closed. After pressure within the right ventricle increases, the pulmonary semilunar valve is forced open, and blood flows into the pulmonary trunk. As the right ventricle relaxes, its pressure falls rapidly, and pressure int he pulmonary trunk becomes greater than in the right ventricle. The black flow of blood forces the pulmonary semilunar valves to close.

27

Blood flow: Blood flows into the right atrium from ...

Blood flows into the right atrium from the superior and inferior vena cava, and the coronary sinus.

28

Blood flows into the right atrium from the superior and inferior vena cava, and the coronary sinus. It then passes which valve?

Blood from the right atrium passes the tricuspid valve on its way to the right ventricle.

29

Blood from the right atrium passes the tricuspid valve on its way to the right ventricle. Which valve does it pass next?

Blood being pumped out of the right ventricle passes the pulmonary semilunar valve.

30

Blood being pumped out of the right ventricle passes the pulmonary semilunar valve. This valve is in the ...

Pulmonary trunk.

31

Blood in the pulmonary trunk flows to the ...

Pulmonary arteries.

32

Blood in the pulmonary arteries reaches the lungs and leaves the lungs in the ...

Pulmonary veins.

33

The pulmonary veins empty into ...

the left atrium

34

Blood in the left atrium passes which valve on its way to the left ventricle?

The bicuspid valve.

35

Blood in the left ventricle passes which valve on its way out of the body?

The aortic semilunar valve.

36

The cardiac muscle is supplied by how many coronary arteries?

Two.

37

The two coronary arteries originate from ..

the base of the aorta, just above the aortic semilunar valve.

38

How does the action potential in the cardiac muscle differ from other muscles?

It has a plateau phase. This is caused by Ca2+ channels closing quite late. The refractory period is also longer.

39

What is meant by the conduction system of the heart?

Contraction of the atria and ventricles is coordinated by specialised cardiac muscle cells in the heart wall that form the conduction system of the heart.

40

What constitutes the conduction system of the heart?

1. The sinoatrial node
2. The atrioventricular node
3. The right and left bundle branches
4. The Purkinje fibers

41

What is the sinoatrial node?

The sinoatrial (SA) node functions as the heart's pacemaker, is located in the superior wall of the right atrium and initiates the contraction of the heart.

42

What is the atrioventricular node?

The atrioventricular (AV) node is located in the lower portion of the right atrium. When action potentials reach the AV node, they spread slowly through it and then into a bundle of specialised cardiac muscle called the atrioventricular bundle. The slow rate of action potential conduction in the AV node allows the atria to complete their contraction before action potentials are delivered to the ventricles.

43

What are the Purkinje fibers?

The Purkinje fibers pass to the apex of the heart and then extend to the cardiac muscle of the ventricle walls. They're simply nerve bundles.

44

What happens if the sinoatrial SA node stops producing action potentials?

Another area, such as the AV node can start making action potentials. This causes a slower heart rate, but is compatible with life.

45

The normal ECG consist of a ....., a ..... and a .....

The normal ECG consists of a P wave, a QRS complex, and a T wave.

46

What causes the P wave?

The P wave results from depolarisation of the atrial myocardium, and the beginning of the P wave preceded the onset of atrial contraction.

47

The QRS complex is a complex. What does it consist of?

The QRS complex consists of three individual waves: the Q, R and S waves.

48

What causes the QRS complex?

The QRS complex results from depolarisation of the ventricles, and the beginning of the QRS complex precedes ventricular contraction.

49

What causes the T wave?

The T wave represents repolarisation of the ventricles, and the beginning of the T wave precedes ventricular relaxation.

50

How can you see the repolarisation of the atria on an ECG?

You can't because it occurs during the QRS complex.

51

Which intervals are interesting when looking at an ECG?

The PQ interval (often commonly called the PR interval, because the Q wave is so small), and the QT interval.

52

What happens during the PQ interval?

During the PQ interval, the atria contracts and begins to relax. At the end of the PQ interval, the ventricles begin to depolarise.

53

What happens during the QT interval?

The QT interval extends from the beginning of the QRS complex to the end of the T wave and represents the length of time required for ventricular depolarisation and repolarisation.

54

Cardiac Cycle:
1. The atria and ventricles are relaxed... and?

1. The atria and ventricles are relaxed. AV valves open and blood flows into the ventricles. The ventricles fill to approximately 70% of their volume.

55

Cardiac Cycle:
1. The atria and ventricles are relaxed. AV valves open and blood flows into the ventricles. The ventricles fill to approximately 70% of their volume.
What happens thus?

2. The atria contract and complete ventricular filling.

56

2. The atria contract and complete ventricular filling.
What happens thus?

3. Contraction of the ventricles causes pressure in the ventricles to increase. Almost immediately, the AV valves close. The pressure in the ventricles continues to increase.

57

Cardiac Cycle:
3. Contraction of the ventricles causes pressure in the ventricles to increase. Almost immediately, the AV valves close. The pressure in the ventricles continues to increase.
What happens thus?

4. Continued ventricular contraction causes the pressure in the ventricles to exceed the pressure in the pulmonary trunk and aorta. As a result, the semilunar valves are forced open, and blood is ejected into the pulmonary trunk and aorta.

58

Cardiac Cycle:
4. Continued ventricular contraction causes the pressure in the ventricles to exceed the pressure in the pulmonary trunk and aorta. As a result, the semilunar valves are forced open, and blood is ejected into the pulmonary trunk and aorta.
What happens thus?

5. At the beginning of ventricular diastole, the ventricles relax, and the semilunar valves close.

59

What is the first heart sound?

The AV valves closing.

60

What is the second heart sound?

The semilunar valves closing.

61

What is systole?

Contraction

62

What is diastole?

Dilation

63

During what ECG interval does the ventricles fill?

PQ

64

How is the pressure in the left ventricle during the PQ interval?

The pressure is largely unchanged. The ventricle is filling at this point, but the bicuspid valve is open.

65

How is the left ventricular volume changed during the PQ interval?

It increases from 70% full to 100% full.

66

What heart sounds can be heard during the PQ interval?

None.

67

How is the pressure in the left ventricle during the QRS complex?

It rises rapidly.

68

How is the left ventricular volume changed during the QRS interval?

It doesn't. This is the period of isovolumetric contraction.

69

What heart sounds can be heard during the QRS complex?

The first heart sound can be heard as the AV valves close.

70

What happens to the pressure in the left ventricle from the end of the S wave until the end of the T wave?

At first, it continues to rise, but later falls off. This is because the semilunar valves have been opened from the end of the S wave.

71

What happens to the left ventricular volume from the end of the S wave until the end of the T wave?

It decreases. This is the period of ejection.

72

What heart sounds can be heard during the end of the S wave until the end of the T wave?

The first heart sound is still audible for a while during this interval.

73

What are murmurs?

Abnormal heart sounds.

74

Diastole kommer mellom hvilke hjertelyder?

Mellom S2 og S1.

75

Systole kommer mellom hvilke hjertelyder?

Mellom S1 og S2.

76

What are the three most common measurements of heart function?

1. Cardiac output (CO)
2. Stroke volume (SV)
3. Heart rate (HR)

77

What is Sterling's law of the heart?

If venous return increases, this increases the preload (the degree to which the ventricular walls are stretched at the end of diastole), and also increases the cardiac output.

78

What is the relationship between hypertension and heart failure?

People suffering from hypertension have an increased after load because their aortic pressure is elevated during contraction of the ventricles. The heart must do more work to pump blood from the left ventricle into the aorta, which increases the workload on the heart and can eventually lead to heart failure.

79

What are baroreceptors?

Baroreceptors are stretch receptors that monitor blood pressure in the aorta and in the wall of the internal carotid arteries, which carry blood to the brain.

80

The baroreceptors communicate blood pressure to ....

the Cardioregulatory center in the medulla.

81

Which hormones has effect on cardiac output?

epinephrine and norepinephrine.

82

A decrease in pH in the blood is often caused by.

Increased CO2 levels.

83

Where is the decrease in blood pH sensed in the way that causes cardiac output to increase?

In the medullas chemoreceptors.