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Flashcards in Cardio W1 Deck (132)
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1

muscarinic receptors of the heart and what acts on them

M2 receptors, acetylcholine

2

inotropic

force

3

chronotropic

HR

4

Frank Starling

as EDV increases, the SV increases

5

beta receptors on the heart and what acts on them

B1 receptors, noradrenaline

6

what does the PR interval indicate

AV node delay

7

what are striation of cardiac muscle caused by

contractile fibres

8

four phases of action potential generation in pacemaker cells

phase 0: Na+ channels open
phase 1: Na+ close, transient K+ efflux
phase 2: Ca++ open (L-type channels)
phase 3: K+ efflux
phase 4: resting potential

9

what is the A band

myosin only

10

what is the I band

between myosin

11

what is the H zone

between actin

12

What is happening when muscle is relaxed

no cross bridge because the actin binding site is blocked by the troponin- tropomyosin complex

13

what is happening when muscle contracts

Ca++ binds to troponin and pulls the troponin-tropomyosin complex away to expose binding site and cross bridge forms

actin-myosin cross bridge forms, power stroke pulls actin inwards during contraction

14

time of pacemaker cell AP vs Ventricular muscle AP

250ms, 800ms

15

what happens to calcium after AP has passed

Ca++ influx ceases and Ca++ goes back into SR by Ca++ATPase (relaxation)

16

what effects the stroke volume?

preload, afterload, myocardial contractility

17

Effect of sympathetic stimulation on frank starling curve and shift?

greater contractility, so for every EVD, there is a greater SV
Frank starling curve shifts to the left

18

How to record BP using kortkoff sounds

record systolic BP when you hear the 1st heart sound, then record diastolic BP when the heart sounds disappear

19

Normal HR

60-100BPM

20

normal systemic BP

90/60mmHg to 120/80mmHg

21

Definition of hypertension

average clinical BP of 140/90mmHg or above and a daytime average of 135/85mmHg or above

22

What is MABP

average arterial BP during a single cardiac cycle involving contraction and relaxation of the heart

23

How to calculate MABP

(2D+S)/3 or DBP+ (PP/3)

24

Normal range for MABP

70-105mmHg

25

what systems regulate BP in long term and their effect on BP

RAAS (increase)
Naturetic peptides
ADH

26

Describe whole RAAS

fall in BP-kidney releases renin- renin causes conversion of angiotensinogen (liver) to angiotensin 1. angiotensin 1 is converted to angiotensin II by ACE (lung vascular endothelium). Angiotensin II causes vasoconstriction, vascular muscle hypertrophy, increased thirst, increased ADH and aldosterone release (adrenal cortex). Aldosterone increased plasma volume and increased BP, water and sodium reabsorption form the kidneys.

27

what is the rate limiting step in RAAS

renin release

28

what releases renin

granular cells

29

what monitors tubular Na+ in kidney tubules

macula densa

30

Physiological closing of S2

pulmonary valve closes before the aortic valve

31

contents of juxtaglomerular apparatus and their function

granular cells (renin release) and macula densa (monitors Na+ in kidney tubules)

32

Three stimuluses of renin release

1. Reduced renal BP due to reduced overall BP
2. Decreased Na+ in kidney tubules
3. Stimulation of renal sympathetic nerves

33

Function of Naturetic peptides and all its actions

To reduced BP by excretion of salt and water is response to cardiac distension or neurohormonal stimuli

also reduce renin release and act as vasodilators

34

Two types of naturetic peptide

ANP 28 AA (atria)

BNP 32AA (ventricles)

35

Name and describe the 4 types of shock

Hypovolaemic (non/haemorrhagic)
Obstructive (TPX, PE, tamponade)
Cardiogenic (eg MI)
Distributive (neurogenic- spinal cord injury, vasoactive-septic or anaphylactic shock)

36

until what point can body compensate for loss in blood volume

until loss of >30% blood volume

37

Amount of exercise adults should do weekly

150 minutes/week moderate exercise or 75 minutes per week of intense exercise

38

Amount of exercise children should do weekly

1h per day for 5 days a week

39

X ray features of heart failure

Alveolar oedema
B lines
Cardiomegaly
Diversion of vessels (upper zone vessel enlargement)
Effusion

40

Events during cardiac cycle

1. Passive Filling (80%)
2. Atrial Contraction
3. Isovolumetric ventricular contraction
4. Ventricular Ejection
5. Isovolumetric ventricular diastole

41

What is the average EDV

130ml

42

What causes the closure of AV valves

when ventricular pressure is greater than atrial pressure

43

when do aortic and pulmonary valve open

when ventricular pressure exceeds pressure in vessels

44

Average stroke volume

70ml

45

4 areas of cardiac auscultation

aortic- 2nd int space, right parasternal edge
pulmonary- 2nd, left parasternal edge
tricuspid- 4th int space, left parasternal edge
mitral- 5th int space, left midclavicular line

46

When does JVP occur and which waves are normal and abnormal

occurs after atrial contraction
a and c wave= normal
v wave= abnormal

a= atrial contraction
c= bulging of tricuspid into atria in ventricular contraction
v= rise in atrial pressure during atrial filling

47

Where is most blood in the body

peripheral veins

48

Diameter of arterioles

30-200 micrometers

49

Diameter in capillaries

4-8 micrometers

50

what are pericytes

connective tissue with contractile properties, outside of capillaries

51

describe the 3 types of capillaries

continuous- no gaps- skin, muscle, nerves, lungs, connective tissue

fenestrated- 50 nanometer pores- gut mucosa, kidney glomeruli, endocrine glands

discontinuous/sinusoidal- large gaps- spleen, bone marrow

52

Diameter of PCV

10-30 micrometers

53

When do PVC become venules

acquire intermittent smooth muscle and 50 micrometers diameter

54

what are valves

inward expansions of the tunica intima in veins

55

what is on the outer layer of the heart

mesothelium

56

core of heart valves

dense irregular connective tissue- the lamina fibrosa which is continuous with the fibrous skeleton of the heart

57

blood supply of the heart valves

valves have no blood vessels

58

Diameter of pacemaker cells and compare to contractile cells

4-8 micrometers
smaller than contractile cells

59

Appearance of pacemaker cells

small, pale

60

Location and Appearance of Purjunke fibres

subendothelial layer
larger than cardiac cells, clear area in the centre and pink in margins- myosin and actin at the periphery

61

Equation for resistance to blood flow

R=nL/r4

62

What regulates blood pressure in arterioles in the short term

Baroreceptor reflex

63

Nervous innervation of arterioles

Sympathetic- a1 adrenoceptors- noradrenaline
(vasomotor tone)

no parasympathetic innervation (except penis and clitoris)

64

Effect of adrenaline on alpha and beta receptors

alpha- vasoconstriction (skin, gut, kidneys)
B2- vasodilation (cardiac and skeletal muscle)

65

Effect of angiotensin II and ADH on vascular smooth muscle

vasoconstriction

66

can extrinsic control of VSM over ride intrinsic control?

No
intrinsic factors can over ride extrinsic factors

67

How in NO produced in vascular endothelial cells

L-arginine via NO synthase

68

why may NO be released

increased BP or chemical signalling

69

Chemicals that cause vasoconstriction of blood vessels

Serotonin, Thromboxane A2, Endothelin, Leukotrienes

70

Factors which increase venous return

blood volume
venomotor tone
respiratory pump
skeletal muscle pump

71

Effect of exercise on frank-Starling curve

Contractility of heart increases- FS curve shifts to the left

72

Describe depolarisation and repolarisation

Depolarisation is becoming more positive
Repolarisation is becoming more negative

73

What does an ECG provide information on?

Rate, Rhythm, Chamber size, axis
main test for MI and ischaemia

74

Contents of 12 lead ECG

3 limb leads ( L1, L2, L3)
3 augmented voltage lead (aVL, aVR, AVF)
6 chest leads (V1-6)

75

Horizontal leads

chest leads V1-V6

76

Vertical leads

AVL, AVR, AVF, L1, L2, L3

77

Which lead is used as the rhythm strip

Lead II

78

Normal Duration of P wave

less than 0.12s (120ms), 0.08-0.1s

79

what is an S wave

downward deflection after R wave

80

what is a q wave

downward deflection before R wave

81

What is a R wave

Upward deflection that does not have to come after Q wave

82

Normal duration of QRS complex

less than 0.1s (less than 100ms)

83

Why is the Twave an upward deflection

repolarisation moving away from seeing electrode

84

Normal duration of PR interval

0.12-0.2ms

85

Normal duration of QT interval

0.44s men, 0.46s in women

86

what are precordial leads

chest leads

87

what are unipolar leads and bipolar leads

augmented voltage leads, limb leads

88

Lateral leads

Lead I and AVL

89

Inferior leads

aVF, LII and LIII

90

what does each chest lead 'look at'

V1-V2- IV septum
V3-V4- anterior heart
V5-V6- lateral (left)

91

positions of each chest lead

V1 4th int space right parasternal
V2 4th int space left parasternal
V3 between V2 and V4
V4 5th int space, midclavicular line (left)
V5 same horizontal level as v4, anterior axillary line
V6 same horizontal level as V4, midaxillary line

92

Duration of one small ECG square

0.04s

93

Speed of ECG paper

25mm/s

94

Calculating HR with normal rhythm

300/no of small squares in R-R interval

95

Calculating HR with abnormal rhythm

no of QRS complex in 30 small squares

96

What is normal sinus rhythm

Normal sinus rhythm is characterized by P waves that are upright in leads I and II of the ECG
but inverted in the cavity leads AVR and V1

97

What can a normal ECG now exclude

MI
Intermittent rhythm disturbances (24h/7day ECG)
Stable angina

98

What investigation for stable angina

Exercise ECG- look for ST changes before/ after exercise (usually not shown at rest)

99

what is TLC

the real or apparent loss of consciousness with loss of awareness, loss of motor control, loss of responsiveness and amnesia for a short duration

100

what is syncope

TLC due to cerebral hypoperfusion which is short and rapid and results in spontaneous recovery

101

Types of syncope

Reflex syncope, Orthostatic hypoperfusion, cardiac syncope

102

Reflex syncope

when there is a fall in HR (cardioinhibition) or vasopressin which causes reduced CO due to neural reflexes via vagal stimulation

103

Types of reflex syncope

vasovagal reflex syncope
situational reflex syncope
carotid sinus reflex syncope

104

Postural hypotension defintion

when there in a change in BP within 3 minutes of standing from lying down by
20mmHg SBP with/without symptoms
10mmHg DBP with symptoms

105

Causes of cardiac syncope

- Arrhythmia (bradycardia or tachycardia)
- Acute MI
- Structural cardiac disease (aortic stenosis, hypertrophic cardiomyopathy)
- Other (PE, Tamponade, TPX)

106

Action of ivabradine and its use

Blocks HCN channels (reduced Na+ Influx/funny current) used in angina to reduce HR

107

What is calcium induced calcium release

when intracellular calcium acting on ryanodine II receptors causes Ca2+ influx from the SR

108

Two methods of calcium efflux

to extracellular space via Na+/Ca2+ exchanger 1 (NCXR)
to SR via Ca2+ATPase (SERCA)

109

Influence of PKA on relaxation

PKA phosphorylates phospholamban, increasing Ca2+ATPase activity therefore increased relaxation

110

Action of PDE

converts cAMP to 5AMP (inactive)

111

Name the catecholamines and describe their selectivity

Dobutamine (B1)
Adrenaline (b over a)
NA (a OVER B)

112

What is dobutamine used in

acute HF, but will cause early death if used in chromic HF

113

Uses of BB

Angina (1st line), HF (Carvedilol, start low, go slow), Hypertension, arrhythmia

114

What is atropine + its effect

Atropine is a non-selective muscarinic antagonist- increases HR

115

use of atropine

used in Bradycardia and ACh poisoning

116

What type of drug is digoxin, its action, and what is it used to treat

Inotropic drug (cardiac glycoside) which increases heart contractility
Na/K ATPase blockade increases Ca2+ influx from SR

used IV in acute HF, oral in chronic HF, HF with AF

117

side effects of digoxin

blurred yellow vision
effect of digoxin is increased in hypokalaemia
oscillatory after potentials (Ca2+ overload)
Arrhythmia
heart block (excessive AV depression)
N+V+D
Gynaecomastia

118

Contraction of VSM

calcium combines with calmodulin to make calcium-calmodulin complex, which activates MLCK.
MLCK phosphorylates MLC- contraction

119

Relaxation of VSM

MLC phosphatase will dephosphorylate MLC-relaxation

120

what activates MLC phosphatase

PKG

121

Action of organic nitrates

metabolism of ON to NO causes relaxation of smooth muscle. reduced preload and afterload. Redirects blood to areas of ischaemia. venodilation at low doses, arterial dilation at higher doses.

122

Types of ON and what they are used in

Isosorbide mononitrate- short term relief (spray/patch)
tablet in stable angina, IV in unstable

Glyceryl trinitrate- prophylaxis (need 8 hour nitrate free period)

used in all types of ANGINA

123

Side effects of ON

Hypotension, headaches, dizziness/syncope, Methaemoglobin (cyanide poisoning treatment), reflex tachycardia (px with BB)

124

types of CCB and what they are used in

Verapamil- heart (dysrhythmia)
amlodipine (vascular- used in hypertension)
diltiazem (heart and vascular)

also used in angina

125

Side effects of CCB

ankle oedema, flushing, hypotension

126

what is bradykinin

potent vasodilator inhibited by ACE

127

SE of ACEI

dry cough, angioneurotic oedema, hypotension, hyperkalaemia (less aldosterone)

128

who is ACEI contraindicated in? who are they good for?

Pregnant/child-bearing age women and bilateral renal stenosis

diabetic neuropathy

129

what are ACEI/ARB used in?

Hypertension (1st line for under 55 non-African/Caribbean, diabetic neuropathy)
Cardiac Failure
Post-MI

130

Use of nicorandil
type of drug
SE

used in refractory angina (NO activity)
K channel opener
mouth ulcer

131

Use of alpha antagonists
SE

Hypertension with prostatic hypertrophy
postural hypotension

132

Describe types of diuretics and side effects

Thiazide diuretics- mild- hypertension
loop diuretics- stronger-HF- hypocalcemia

Hypokalaemia and Hyponatremia
Gout, hyperglycaemia therefore diabetes, impotence