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Flashcards in Cardiology Deck (79):
1

What is the pericardium?

Membrane that surrounds and protects the heart

2

What are the two parts (layers) of the pericardium?

Fibrous pericardium
Serous pericardium

3

What is the inner visceral layer of the serous pericardium also called?

Epicardium

4

Normally how much pericardial fluid is in the pericardial cavity?

15-50ml

5

What is the function of the pericardial fluid?

Reduces friction between the two layers of serous pericardium as the heart moves

6

What are the three layers of the heart wall?

Epicardium
Myocardium
Endocardium

7

What is the myocardium?

A thick, helical middle layer of the heart wall composed of cardiac muscle

8

What is the endocardium?

The thin internal layer of the heart wall made of endothelium and sub endothelial connective tissue, or a lining membrane that covers the valves

9

What is the auricle of the heart?

A wrinkled pouch like structure on the anterior surface of the atria

10

What is the purpose of the auricles of the heart?

Each one slightly increases the capacity of its atrium so it can hold a larger volume of blood

11

What are sulci and what do they contain?

They are grooves on the surface of the heart that contain coronary blood vessels and a variable amount of fat

12

What does each sulcus mark?

The external boundary between two chambers of the heart

13

What does the deep coronary sulcus mark?

It encircles the heart and marks the external boundary between the superior atria and inferior ventricles

14

What marks the external boundary of the ventricles on the heart?

Anteriorly - the anterior interventricular sulcus
Posteriorly - the posterior interventricular sulcus

15

From what 3 blood vessels does the right atrium receive blood?

Superior vena cava
Inferior vena cava
Coronary sinus

16

What is a prominent feature in the interatrial septum, and what is it a remnant of?

Fossa ovalis - remnant of foramen oval

17

Where is the sinoatrial node located?

Right atrium, where the SVC joins the atrial tissue mass

18

What causes activation of the pacemaker of the heart without external activation?

The SA node has an unstable resting potential and is repeatedly depolarising to the threshold spontaneously

19

What structures conduct the impulse generated by the SA node across the left and right atrium?

Internodal tracts and Bachmanns bundle

20

What are the three internal tracts that transmit impulses across the atria?

Anterior
Wenkebach
Thorel's

21

The heart is supplied by autonomic fibres from where?

The cardiac plexus

22

Where is the deep cardiac plexus located?

On the anterior surface of the bifurcation of the trachea

23

Where does the superficial cardiac plexus lie?

On the arch of the aorta

24

Is the cardiac plexus sympathetic or para-sympathetic?

Both

25

What fibres make up the parasympathetic nervous supply of the heart?

Presynaptic fibres of the vagus nerve

26

Name three effects of sympathetic stimulation to the heart.

Increased heart rate
Increased impulse conduction
Increased force of contraction

27

Name three effects of parasympathetic stimulation to the heart.

Slowed heart rate
Reduced force of contraction
Constrict coronary arteries

28

What do postsynaptic parasympathetic fibres release and what does it bind to?

Acetylcholine - muscarinic receptors

29

When fluid is pumped through a closed system, what two factors determine its flow?

Pressure and resistance

30

According to Darcy's Law, what is mean arterial blood pressure equal to?

Cardiac output multiplied by total peripheral resistance
MABP = CO x TPR

31

What is laminar flow?

Also known as streamline flow, occurs when a fluid flows in parallel layers, with no disruption between layers

32

What are the primary areas in the cardiovascular system responsible for resistance to blood flow?

Mainly arterioles
To a lesser extent, capillaries and venules too

33

Where is the steepest fall in blood pressure?

Arterioles

34

What is elastance?

Quality of recoiling or returning to an original form after removal of pressure.
Way to describe the elastic properties of a blood vessel

35

What is compliance? (in relation to vessels)

Ability of a vessel to distend and increase volume with increasing transmural pressure

36

Which part of the cardiovascular system has the highest compliance?

veins and venules

37

What percentage of total blood volume is normally in the veins and venules?

70%

38

What is the difference in compliance between arteries and veins?

Veins are about 20 times more compliant than arteries

39

In blood vessels, what is the transmural pressure equal to?

Pressure inside the vessel minus the interstitial pressure

40

What does the Law of Laplace state about vessels?

The total circumferential wall tension at equilibrium is counterbalanced by the total pressure in the lumen.
i.e. the tension in the wall of a blood vessel depends on the radius, thickness of the wall and the transmural pressure

41

What does the elastic recoil of the aorta do to the blood flow?

It converts what would be intermittent flow into a continuous, albeit pulsatile, flow through the arterial system

42

What are Windkessel vessels?

Aorta and large elastic vessels

43

What is pulse pressure?

The difference between systolic and diastolic pressure

44

What is the mean arterial blood pressure?

Pressure averaged over the whole cardiac cycle

45

In terms of percentage, how much time does the heart spend in diastole?

60%

46

What is the mean arterial blood pressure roughly equal to?

Diastolic pressure, plus one third of the pulse pressure

47

What are Korotkoff sounds?

Varying sounds heard with a stethoscope she measuring blood pressure

48

What measures mean arterial blood pressure and where are they located?

Arterial baroreceptors
Located in the wall of the aortic arch and in the carotid sinus

49

What is the carotid sinus?

An enlarged part of the internal carotid artery just after it rises from the common carotid artery

50

What do atrial stretch receptors measure?

Atrial blood volume

51

A rise in levels of which ion causes contraction of the heart muscle?

Calcium

52

What category of factors alter the contractility of cardiac muscle?
And name one.

Inotropic factors
Noradrenaline

53

What type of agents affect atrioventricular conduction?

Dromotropic agents

54

How do chronotropic agents affect heart rate?

By affecting nerves controlling the heart or changing the rhythm produced by the SA node

55

In a heart beat, what is the absolute refractory period?

A period immediately following the firing of a nerve fibre when it cannot be stimulated no matter how great a stimulus applied

56

What is the relative refractory period?

The period shortly after the firing of a nerve fibre when partial depolarisation has occurred and a greater than normal stimulus can stimulate a second response

57

What is first-degree (incomplete) heart block?

Abnormally slow conduction in the AV node, where delay is greater than normal

58

How does first-degree heart block appear on an ECG?

An extended PR interval

59

What happens to the impulses in second-degree heart block?

A fraction of the impulses from the atria are conducted to the ventricles

60

How is second-degree heart block Mobitz type II seen on an ECG?

Ventricular contraction is only initiated every second (2:1) or third (3:1) atrial contraction

61

What is seen on an ECG in Wenkebach block (second-degree heart block Mobitz I)?

The PR interval progressively lengthens until there is no transmission from atria to ventricles and a QRS complex is missed. The cycle then begins again

62

What happens in third-degree heart block?

Conduction between atria and ventricles is abolished

63

What can cause third-degree heart block?

Ischaemic damage to nodal tissue or the bundle of His

64

What does third-degree heart block: AVN escape look like on ECG?

Complete dissociation between P wave and QRS complex. Narrow QRS (<0.12s), about 40bpm

65

What does third-degree heart block: ventricular escape look like on ECG?

Complete dissociation between P wave and QRS complex. Wide QRS (>0.12s). Heart rate usually down to less than 20bpm

66

What does bundle branch block look like on ECG?

Wide QRS complex, usually with a bit of a M or W shape, showing that activation is delayed from one side to the other

67

What does the Frank-Starling law of the heart state?

That stroke volume of the heart increases in response to an increase in the volume of blood filling the heart, when all other factors remain constant

68

What is an important consequence of Starlings law of the heart, in regards to stroke volume?

That stroke volume between the left and right ventricles are matched

69

Which law is Darcy's law analogous to?

Ohm's law

70

Which vessels are capacitance vessels and why?

Veins, because they can serve as blood volume reservoirs

71

What binds to beta1-receptors?

The catecholamines - noradrenaline and adrenaline

72

What does activation of cardiac beta1-receptors result in?

Positive inotropic effect = increases contractility
Positive chronotropic effect = increases heart rate

73

What can cause aortic stenosis?

Calcified valves
Congenital bicuspid valve
Rheumatic fever

74

What is the typical history of aortic stenosis?

Syncope
Angina
Dyspnoea

75

What is the character of the pulse like in aortic stenosis?

Slow rising, narrow pulse pressure

76

What is the management for aortic stenosis?

Aortic valve replacement
Balloon Valvuloplasty
Medical flow up - for mild-moderate

77

What is a TAVI?

Transcutaneous Aortic Valve Implantation

78

What is infective endocarditis?

Infection of endocardium or vascular endothelium

79

What are some signs of infective endocarditis?

Sepsis
May have valve regurgitation
New heart murmur
Janeway lesions