Lecture 7 - structure of the cardiovascular system Flashcards Preview

1060 Human form and function > Lecture 7 - structure of the cardiovascular system > Flashcards

Flashcards in Lecture 7 - structure of the cardiovascular system Deck (92):
1

What does the pulmonary circuit do?

The pulmonary circuit carries blood from the heart to the lungs and from there oxygenated blood is returned to the heart.

2

What is the pericardium?

 

A connective tissue sheath

The heart is enclosed in the pericardium which ensures that it is maintained in its position in the thorax and that its actions are friction free.

 

3

How many layers does the pericardium have?

 

3.

An outer fibrous layer which anchors the heart to the diaphragm, the great vessels and the anterior chest wall thus maintaining its position. The inner layers are the visceral and parietal pericardium. The visceral layer (epicardium) is adherent to the heart and the parietal pericardium lines the inner surface of the fibrous layer. A small fluid filled space separates the visceral and parietal pericardia lubricating and reducing friction between the surfaces as the heart beats.

 

4

What is cardiac tamponade?

compression of the heart by an accumulation of fluid in the pericardial sac.

5

Where does the right atrium receive blood from?

 

superior vena cavae, inferior vena cavae  and coronary sinus

 

6

Which ventricle is bigger, and why?

 

The Left ventricle is bigger 

The left ventricle, although containing the same volume of blood as the right is larger due to due to the thicker walls which enables sufficient pressure to be generated to push the blood through the systemic circuit

 

7

Where does the heart get its blood supply from?

The coronary arteries

8

What are the atrioventricular valves?

The AV valves prevent backflow from the ventricles to the atria when the ventricles are contracting.

There are three elements to the valves:
1. The papillary muscles

2. The chordae tendineae

3. The cusps of the valves 

 

When the ventricle is relaxed the chords are loose and the valve offers no resistance to the flow of blood from the atrium to the ventricle. Contraction of the papillary muscles (one of the first areas to of the ventricle to contract) tenses the cords which are attached to the cusps. Thus when the ventricle contract and pushes the blood towards the infundibulum the cusps swing together preventing the blood flowing back to the atrium and the tense chords prevent them everting. 

9

What are the 3 elements to the AV valves?

1. The papillary muscles 2. The chordae tendinea 3. The cusps of the valves

10

How many heart sounds are there?

 

4

The first 2 are the closing of the valves, first ‘lubb’ followed by ‘dubb’. The first (S1) is the closing of the AV valve as the ventricle contract and the second (S2) occurs when the semilunar valves close (ventricles relax and begin to fill). The third (S3) and for the(S4) are much fainter and difficult to hear in the normal heart. S3 is associated with the filling of the ventricles and S4 with atrial contraction. If the AV valves do not close properly then regurgitation can occur creating a gurgling sound known as a heart murmur.

 
 

Using a stethoscope clinicians listen to the heart sounds which are the closing of the valves. It is not possible to listen directly as the sound has to pass through the pericardium, surrounding tissue and the chest wall therefore the placement of the stethoscope differs to the exact position of the valve. 

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11

What is heart murmur?

If the AV valves do not close properly then regurgitation can occur creating a gurgling sound known as a heart murmur.

12

What are arteries and veins named after?

Region. E.g. abdominal aorta

13

 

 

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Cut edge of epicardium

 

14

 

 

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Apex of heart

 

15

 

 

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Fibrous attachment to diaphragm

 

16

 

 

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Pericardial cavity

 

17

 

 

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base of heart

 

18

 

 

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Cut edge of parietal pericardium

 

19

 

 

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Fibrous tissue of pericardial sac

 

20

 

 

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Areolar tissue

 

21

 

 

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Mesothelium

 

22

 

 

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Apex of the heart

 

23

 

 

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Base of heart

 

24

 

 

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Diaphragm

 

25

 

 

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First rib

 

26

 

 

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Left Lung

 

27

 

 

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Parietal Pericardium

 

28

 

 

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Right lung (middle lobe)

 

29

 

 

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Thyroid gland

 

30

 

 

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Trachea

 

31

 

 

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Arch of aorta

 

32

 

 

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Crista terminalis

 

33

 

 

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Fossa ovalis

 

34

 

 

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Inferior vena cava

 

35

 

 

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Limbus of fossa ovalis

 

36

 

 

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Musculi pectinati

 

37

 

 

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Opening of coronary sinus

 

38

 

 

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Right auricle

 

39

 

 

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Right ventricle

 

40

 

 

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Superior vena cava

 

41

 

 

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Tricuspid valve

 

42

 

 

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Valve of coronary sinus

 

43

 

 

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Valve of inferior vena cava

 

44

 

 

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Aortic sinus

 

45

 

 

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Left coronary artery

 

46

 

 

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Lunule

 

47

 

 

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Nodule

 

48

 

 

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Posterior semilunar cusp

 

49

 

 

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Right coronary artery

 

50

 

 

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Arch of Aorta

 

51

 

 

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Inferior vena cava

 

52

 

 

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Left atrium

 

53

 

 

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Left auricle

 

54

 

 

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Left ventricle

 

55

 

 

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Mitral valve

 

56

 

 

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Pulmonary arteries

 

57

 

 

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Pulmonary veins

 

58

 

 

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Anterior cardiac veins

 

59

 

 

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Anterior interventricular artery

 

60

 

 

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Aortic arch

 

61

 

 

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Ascending aorta

 

62

 

 

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Atrial arteries

 

63

 

 

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Great cardiac vein

 

64

 

 

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Left coronary artery

 

65

 

 

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Marginal artery.

 

66

 

 

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Pulmonary trunk

 

67

 

 

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Right coronary artery

 

68

 

 

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Small cardiac vein

 

69

 

 

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Anterior papillary muscle

 

70

 

 

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Arch of aorta

 

71

 

 

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Chordae tendineae

 

72

 

 

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Conus arteriosus

 

73

 

 

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Inferior vena cava

 

74

 

 

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Left auricle

 

75

 

 

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Ligamentum arteriosum

 

76

 

 

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Posterior papillary muscle.

 

77

 

 

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Pulmonary trunk

 

78

 

 
 

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Pulmonary valve:

Anterior semilunar cusp

Right semilunar cusp

Left semilunar cusp

 
 

79

 

 

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Right atrium

 

80

 

 

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Right auricle

 

81

 

 

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septal papillary

 

82

 

 

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Septomarginal trabecul

 

83

 

 

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Superior vena cava

 

84

 

 

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Trabeculae carneae

 

85

 

 

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Tricuspid valve:

Anterior cusp

Septal cusp

Posterior cusp

 

86

The Heart and Circulatory Systems ??

The pumping of the heart drives the blood through the pulmonary and systemic circuits. It is a closed system with each circuit starting and ending at the heart. The pulmonary circuit carries blood from the heart to the lungs and from there oxygenated blood is returned to the heart. The oxygenated blood is transported via the systemic system around the body and returns the blood to the heart. The systems contain about 5 litres of blood, the pressure and distribution of which is controlled by the blood vessels.

The heart is enclosed in a connective tissue sheath (the pericardium) which ensures that it is maintained in its position in the thorax and that its actions are friction free.
The pericardium consists of three layers:

An outer fibrous layer which anchors the heart to the diaphragm, the great vessels and the anterior chest wall thus maintaining its position.
The inner layers are the visceral and parietal pericardium. The visceral layer (epicardium) is adherent to the heart and the parietal pericardium lines the inner surface of the fibrous layer. A small fluid filled space separates the visceral and parietal pericardia lubricating and reducing friction between the surfaces as the heart beats. 

87

The Chambers of the Heart ??

The heart consists of 4 chambers, 2 atria and 2 ventricles. The atria are the receiving chambers; venous return from the body to the right atrium and arterial blood from the lungs to the left atrium. Blood is expelled from the heart via the ventricles with blood from the right ventricle directed towards the lungs and from the left to the aorta to be distributed throughout the body. 

 

The right atrium receives blood from the superior and inferior vena cavae and the coronary sinus. The posterior wall of the right atrium and the interatrial septum are smooth walled whilst the anterior wall contain prominent muscular ridges (musculi pectinati). There is a depression in the interatrial septum (fossa ovalis) which is a remnant of the foramen ovale through which oxygenated blood flowed during foetal development to bypass the lungs.

The left atrium forms the base (posterior) surface of the heart. The 4 pulmonary veins open into its posterior wall which is smooth. The anterior wall is continuous with the left auricle which contain musculi pectinati.

The right ventricle receives the blood from the right atrium through the atrioventricular valve. The internal surface of the ventricle contains a series of muscular ridges (trabeculae carneae). The papillary muscles are attached to the cusps of the AV valve by the chordae tendineae. The superior aspect tapers to a smooth walled area, the infundibulum, ending at the pulmonary valve.

The left ventricle lies anteriorly and on the left of the heart. The muscular ridges are more delicate than those in the right. There are papillary muscles attached to the cusps of the AV valve by chordae tendineae. 

88

89

Where does the right ventrical receive its blood from??

The right ventricle receives the blood from the right atrium through the atrioventricular valve. 

90

what are trabeculae carneae ??

The internal surface of the ventricle contains a series of muscular ridges (trabeculae carneae) 

91

Why does the heart need its own blood supply??

Cardiac muscle requires a reliable arterial supply as it is continually active. The blood passing through the chambers of the heart does not nourish the heart and therefore it requires its own blood supply. The coronary arteries (right & left) originate at the base of the aorta in a dilated area known as the aortic sinus.

The right coronary artery supplies the right atrium, parts of both ventricles and the sinu atrial and atrioventricular nodes of the conducting system.

The left coronary artery supplies blood to the left ventricle, left atrium and the interventricular septum.
In most tissues of the body the arteries anastomose with each other. These anastomoses (communications) between multiple branches of an artery provide potential detours for blood flow in case the usual pathway is obstructed. There is very little anastomoses of the coronary vessels and they are termed end arteries. If an arteries is blocked there is no blood supply to the tissue and it will die as is the case in a myocardial infarction.

Venous drainage is by the cardiac veins with several draining into the great cardiac vein which empties into the coronary sinus which enters the right atrium. 

92

what do the The Semilunar Valves do?

The pulmonary and aortic semi lunar valves prevent back flow in the right and left ventricles respectively. As they are in the walls of the blood vessels the position of the valves is relatively stable. They consists of a thin layer of connective tissue covered by endothelium. The connective tissue is thickened along its free margin where it forms a nodule.

The semilunar valves are forced apart by the ejection of blood from the contracting ventricle. As this ends the elastic recoil of the vessels forces blood back to the ventricles, resulting in the ballooning out of each valvule so that the free margins are forced together to form a ‘Y'.

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