Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PCS Unit 2 - Distribution, Defence and Repair > Week 4 - Cardiac cycle > Flashcards

Week 4 - Cardiac cycle Flashcards

1
Q

What is the function of the cardiovascular system?

A

to supply and remove materials to tissues around the body

examples of these materials include, glucose, oxygen, carbon dioxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the basal output of the heart?

A

5 litres a minute

can be 25-30 when exercising

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the role of the pericardium?

A

to prevent excessive expansion of the heart

fixes the heart to the mediastinum

protection against infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the two atrioventricular valves and where are they located?

A

mitral - left side of heart

tricuspid - right side of heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many cusps do the semilunar valves have?

A

both have 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How many cusps to the atrioventricular valves have?

A

mitral - bicuspid - 2

tricuspid - 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the chordae tendineae?

A

chord like tendons (80% collagen, 20% elastin) that attach the papillary muscles to the tricuspid valve and mitral valve in the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the purpose of the papillary muscles?

A

to prevent inversion of the valves during systole

ventricles are contracting, blood must not go back into atria but out to body or lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a chronotrophic change?

A

a change in rate of contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an inotropic change?

A

a change in force of contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What nerve supplies the parasympathetic nerve supply to the heart?

A

vagus CN X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the actions of the b1 adrenergic receptor in cardiac muscle?

A

increase cardiac output by:

increasing heart rate in SA node (chronotropic effect)

increasing strength of atrial and ventricular contraction (inotropic effect)

increases conduction of AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the receptor of the parasympathetic nervous system in the heart?

A

M2 muscarinic receptor

slow down heart rate

reduce contractile force of atria

reduce conduction velocity of SA and AV nodes

little effect on ventricular muscle due to sparse innervation of ventricles by parasymathetic nervous sytem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How long does one cardiac cycle last?

A

0.8 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How long does the heart spend in diastole?

A

0.4 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How long is atrial systole?

A

0.1 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How long is ventricular systole?

A

0.3 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How many heart sounds are produced?

A

4 - usually only two are audible (S1 and S2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What causes the aortic valve to open?

A

when aortic pressure is slighly below left ventricular pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What term is typically used to refer to ventricular contraction while no blood is being ejected?

A

isovolumetric contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

During what phase does most blood enter the ventricle?

A

atrial diastole

the movement of blood into the ventricles is passive and caused by a pressure difference

atrial systole ensures the last bit of blood has been ejected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The first heart sound represents which portion of the cardiac cycle?

A

the closing of the atrioventricular valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The second heart sound represents which phase of the cardiac cycle?

A

closure of the semilunar valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Ventricular relaxation immediately follows:

a) atrial repolarization
b) ventricular depolarization
c) atrial depolarisation
d) ventricular repolarization

A

d

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is stenosis of a heart valve?

A

valve does not open completely causing turbulent flow

associated with calcification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the characteristics of cardiac muscle?

A

striated, mononuclear, smaller cells than skeletal muscle, cells connect to each other via desmosomes and gap junctions, no stem cells

27
Q

What are intercalated discs?

A

cell junctions that link adjacent cardiac myocytes together to form a synctium

contain desmosomal junctions, adherent-type junctions and communicating gap junctions

28
Q

What are desmosomes?

A

cell structure specialised for cell to cell adhesion

29
Q

What doesthe term ‘calcium induced calcium release’ mean?

A

refers to the trigger Ca2+ causing the sarcoplasmic reticulum to release more calcium

30
Q

What triggers the initial Ca2+ influx into the cell?

A

a cardiac action potential

31
Q

What are the three patterns of cardiac action potentials?

A

ventricular, atrial and sino-atrial node

32
Q

What does phase 0 on this graph refer to?

A

ventricular depolarisation

33
Q

What is the resting membrane potential of the ventricular action potential?

A

-90mV

K+ are open and K+ moves into the cell creating a negative membrane potential

34
Q

What is a myogenic rhythm?

A

cardiac muscle can contract rhythmically without nervous input

35
Q

At what rate do action potentials of the sino-atrial node fire?

A

100 bpm

36
Q

What is the route of conduction of electrical impulses through the heart?

A
37
Q

What causes phase 2 (prolonged plateau) of the ventricular action potential?

A

opening of L-type voltage-gated calcium channels causes inward Ca2+ current

this balances out the outward K+ causing a plateau

38
Q

What does an atrial action potential look like?

A

similar to ventricular, less obvious plateau, slower repolarisation

39
Q

What is the ‘pacemaker potential’‘?

A

the slow positive increase in voltage across the cell membrane after each action potential

represents the non-contracting time between heart beats (diastole)

40
Q

What are the bipolar (limb) leads?

A

Lead I

Lead II

Lead III

41
Q

How is Lead I connected?

A

negative input connected to right arm

positive input connected to left arm

42
Q

What does Lead I record?

A

the wave of excitation moving between the right and left sides of the heart

REMEMBER: wave of excitation always passes from negative to postive

43
Q

How is Lead II connected?

A

negative input connected to right arm

positive input connected to left leg

44
Q

What does Lead II record?

A

records excitation moving between right upper portion of heart to the apex of the venticle

45
Q

How is Lead III connected?

A

positive input connected to left leg

negative input connected to left arm

46
Q

What does Lead III record?

A

records excitation moving between left atrium to the apex of the ventricle

47
Q

What are the two types of unipolar lead used in the recording?

A

3x augmented limb leads

6x chest leads

48
Q

What do unipolar leads do?

A

record voltage between a single lead and an ‘earth’ lead

49
Q

What is the general direction of depolarisation of the heart known as?

A

the cardiac axis

electrical activity spreads from 11 o clock to 5 o clock

50
Q

What causes an upwards deflection on the ECG trace?

A

an action potential depolarisation moving towards the electrode connected to the positive input of the amplifier

51
Q

What does the P wave correspond to on an ECG trace?

A

atrial depolarisation

52
Q

What does the QRS complex correspond to on an ECG trace?

A

ventricular depolarisation

53
Q

What does the T wave correspond to on an ECG trace?

A

ventricular repolarisation

54
Q

What are the septal leads?

A

V1-V2

55
Q

What are the inferior leads on an ECG?

A

II, III, aVF

56
Q

What are the anterior leads?

A

V3-V4

57
Q

What are the lateral leads?

A

V5, V6, I, aVL

58
Q

What might rarely cause the pathological 4th heart sound?

A

atrial contraction

59
Q

How do you calculate mean arterial pressure?

A

diastolic pressure + 1/3 pulse pressure pulse pressure = systolic - diastolic pressure

60
Q

What physical factors affect arterial blood pressure?

A

arterial blood volume arterial compliance

61
Q

What are the key physiological factors that determine arterial blood pressure?

A

cardiac output peripheral resistance

62
Q

Why is the mean arterial pressure not simply an average of systolic and diastolic pressures?

A

diastole lasts longer than systole so has a greater effect on the mean pressure

63
Q

How does aortic valve regurgitation affect stroke volume?

A

stroke volume increases because there is a greater volume of blood in the ventricle failure of the aortic valve to close properly causes a back flow of blood into the left ventricle increasing stroke volume

64
Q

What is Starling’s law of the heart?

A

an increase in cardiac stretch increases the strength of contraction (greater stretch, greater force if contraction)

PCS Unit 2 - Distribution, Defence and Repair (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions