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Flashcards in Lecture Notes Deck (114):
1

What is systolic BP?

Pressure when heart contracts

2

What is diastolic BP?

Pressure when heart relaxes

3

Which portion of the cardiac cycle is longer and by how much?

Diastolic is 2x as long as the systolic

4

Formulas for MAP?

MAP=COxTPR
MAP= 2xdiastolic pressure + systolic pressure/3

5

Forumla for CO?

CO=SVxHR

6

What is the cardiac output?

Volume pumped by each ventricle per minute

7

What is stroke volume?

Volume pumped by each ventricle per heart beat

8

When is the 1st korotkoff sound heard?

At peak systolic pressure

9

What sound signifies diastolic pressure?

5th korotkoff sound

10

What is the total peripheral resistance?

Sum of resistance of all peripheral vasculature

11

Where are the baroreceptors?

Aortic arch and carotid sinus

12

What are the major resistance vessels?

Arterioles

13

What responds to acute changes in blood pressure?

Baroreceptors

14

What nerves transmit signals from the baroreceptors?

Carotid IXth CN
Aortic Xth CN

15

What do baroreceptors do when you stand up and MAP decreases?

Rate of firing decreases

16

What effect does a decrease in the rate of firing of baroreceptors have on the heart?

Vagal tone decreases
Sympathetic tone increases

17

What changes do the baroreceptors bring about to increase MAP?

increase HR, increase SV, increase TPR

18

Which 3 hormone systems regulate ECF fluid volume?

Rennin-Angiotensin-Aldosterone System
Atrial natriuretic Peptide
Anti diuretic hormone

19

Where is angiotensinogen released from?

Liver

20

Where is rennin relaxed from?

Kidney

21

What does rennin convert?

Angiotensinogen to angiotensin 1

22

What converts to angiotensin 1 to 2?

Angiotensin converting enzyme (ACE)

23

What does angiotensin II act on and what does this cause?

Adrenal cortex which releases aldosterone

24

What effect does aldosterone have?

Increase sodium and water reabsorption
Increased PV
Increased Blood pressure

25

What effect foes angiotensin II have?

Increase TPR
Increase ADH release
Increase thirst

26

What is the rate limiting step in the RAAS?

Rennin secretion

27

What is ANP released in response to?

Atrial distension

28

What does ANP cause?

Causes excretion of salt and water in the kidneys

29

What effect does ANP have on blood volume and BP?

Decreases them

30

What effect does ANP have on rennin release?

Decreases it

31

Where is ADH synthesised?

Hypothalamus

32

What stimulates the secretion of ADH?

Decreased ECF volume
Increased ECF osmolarity

33

What effect does AHD have?

Increases reabsorption of water
Increases ECF and Plasma Volume
Increases CO and BP

34

What is it called when the heat if able to beat in the absence of external stimuli?

Auto rhythmicity

35

Where does excitation of the heart originate?

In the sino atrial node

36

Where is the SA node located?

In the upper right atrium

37

How is the action potential generated in the SA cells?

Pace maker potential take the membrane potential to a threshold

38

What causes the pacemaker potential?

Reduction in K efflux
Slow Na influx

39

What causes the rising phase of the action potential?

Activation of voltage gated Ca channels
Resulting in Ca influx

40

What causes the falling phase of the action potential?

Activation of K channels
K efflux

41

How is excitation spread in atrium and ventricular muscle?

Via gap junctions

42

How does excitation in the heart spread?

SA node - AV node - Bundle of His - Left and right branches - Purkinje fibres

43

Where is the AV node located?

Base of right atrium

44

What is the only point of electrical contact between atrium and ventricles?

AV node

45

Where is conduction delayed?

AV node

46

What causes the rising phase of the ventricular muscle potential?

Na influx

47

What causes the plateau phase of the ventricular muscle potential?

Ca influx

48

What causes the falling phase of the ventricular muscle potential?

K efflux

49

What effect does sympathetic stimulation have on HR?

Increases it

50

What is the nerve supply to SA and AV nodes?

Vagus nerve

51

When is atropine used?

In bradycardia

52

What effect does vagal stimulation have on the slope of the pacemaker potential?

Decrease it

53

What effect does parasympathetic stimulation have on HR?

Slows it

54

What is the parasympathetic transmitter?

Acetylcholine

55

What is the sympathetic transmitter?

Noradrenaline

56

What are the 5 phases of the cardiac cycle?

1 - Passive filling
2- Atrial contraction
3 - Isovolumetric ventricular contraction
4 - Ventricular ejection
5- Isovolumetric ventricular relaxation

57

What % of ventricles fill by passive filling?

80%

58

What does P wave in ECG signal?

Atrial depolarisation

59

When does atria contact in relation to ECG?

Between the P wave and the QRS complex

60

When does ventricular contraction start in relation to the ECG?

After the QRS complex

61

What does T wave signal in ECG?

Ventricular depolarisation

62

What causes the first heart sound?

The closure of the mitral and tricuspid valves

63

What does S1 herald?

Beginning of systole

64

What causes the 2nd heart sound?

Closure of the aortic and pulmonary valves

65

What does S2 herald?

End of systole and beginning of diastole

66

What type of muscle is cardiac muscle?

Striated

67

How is muscle tension produced?

Sliding of actin filaments on myocin

68

What is the refractory period?

A period following an AP in which is it not possible to produce another AP

69

What does SV =?

EDV-ESV

70

What is a positive inotropic effect?

Increase in force of contraction

71

What determines end diastolic volume?

Venous return

72

What is a positive chronotropic effect?

Increase in HR

73

What does the starling law state?

The more the ventricle is filled with blood the greater the volume of ejected blood will be during systolic contraction

74

Will increase sympathetic discharge cause vasoconstriction or vasodilation?

Constriction

75

What are the capacitance vessels?

Veins - hold most volume during rest

76

Does angiotensin II cause vasoconstriction or vasodilation?

Vasoconstriction

77

How does sympathetics stimulation increase the HR?

Increases rate of firing by the SA node
Decreasing AV nodal delay
Increases force of contraction

78

4 chronic responses to exercise?

Decrease in sympathetic tone
Increase in parasympathetic tone
Cardiac remodelling
Decreased aterial stiffness

79

3 effects of nitrates on the vasculature?

Venorelaxation, arteriolar dilatation, increased coronary blood flow

80

Two examples of organic nitrates?

Glyceryltrinitrate and isosorbide mononitrate

81

2 unwanted effects of nitrates?

Repeated administration may cause diminished effect
Headaches

82

How do ACE inhibitors work?

Block the conversion of angiotensin 1 to angiotensin II

83

How do AT1 receptor antagonists work?

Block the agonist action of angiotensin II at AT1 receptors in a competitive manner

84

What effect does an ACE inhibitor have?

Causes venous and arterial dilatation - Decreasing TPR and so BP

85

2 adverse effects of ACE inhibitors?

May initially cause hypotension
Dry cough

86

What type of drugs would you prescribe if patient cannot tolerate cough of ACE inhibitor?

AT1 receptor antagonist

87

Contraindications of ACE inhibitors and AT1 receptor antagonists?

Pregnancy and bilateral renal artery stenosis

88

3 indications for ACE inhibitors and AT1 receptor antagonists?

Hypertension, cardiac failure, post MI

89

What does stimulation of beta 1 receptors cause?

Increase HR, Force and AV node condition velocity

90

What does stimulation of beta 2 receptors cause?

Bronchiole and blood vessel relaxation

91

How do Beta blockers treat angina?

Decrease myocardial O2 requirement

92

How do Beta blockers treat hypertension?

Reduce cardiac output, reducing rennin release from kidney

93

How do calcium antagonists work?

Prevents opening of L type channels and so limit calcium influx

94

Name 3 calcium antagonists?

Verapamil, amlodipine, diltiazem

95

Calcium antagonist in atrial fibrillation?

Verapamil

96

Uses of thiazide diuretics?

Mild heart failure, hypertension,

97

Uses of loop diuretics?

Acute pulmonary oedema

98

1 Example of thiazide diuretic?

Bendroflumethiazide

99

1 example of a loop diuretic?

Furosemide

100

1 example of an ACE inhibitor?

Lisinopril

101

1 example of an AT1 receptor antagonist?

Losartan - 'sartans'

102

2 examples of Beta blockers?

Atenolol, bisoprolol

103

How does Ivabradine work?

Selective blocker of HCN channels, used to slow heart rate

104

Effect of beta adrenoreceptor agonists on the heart?

Increase force, rate, CO and O2 consumption
Decrease cardiac efficiency

105

Name 2 beta adrenoreceptor agonists?

Adrenaline and dobutamine

106

Is propanolol a selective beta blocker or not?

Not selective

107

Name 2 selective Beta 1 blockers?

Metoprolol and atenolol

108

6 adverse effects of Beta blockers?

Bronchospasm, Aggravation of cardiac failure, bradycardia, hypoglycaemia, fatigue, cold extremities

109

Name one non selective muscarinic receptor antagonist?

Atropine

110

Clinical uses of atropine?

To reverse bradycardia following an MI,

111

Is digoxin positively or negatively inotropic?

Positively

112

What type of drug is digoxin?

Cardiac glycoside

113

What effects does digoxin have on the heart?

Slows SA node discharge, Slow AV node conduction, increases refractory period

114

2 Adverse effects of digoxin?

Heart block, propensity to cause dysrythmias