Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

1st Year - Cardiology > Physiology 3 - The Cardiac Cycle > Flashcards

Physiology 3 - The Cardiac Cycle Flashcards

1
Q

What are the events during the cardiac cycle?

A
  1. Passive Filling2. Atrial Contraction3. Isovolumetric ventricular Contraction4. Ventricular Ejection5. Isovolumetric ventricular relaxation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens during passive filling?

A

The pressure in the atria and ventricles is close to 0.AV valves open so that venous return flows into the ventricles.

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

What causes the flow of blood during passive filling?

A

A small pressure gradient.

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

What is the pressure in the aorta during passive filling?Is the aortic valve open?

A

80mmHgNo

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

How full, roughly, do the ventricles become during passive filling?

A

About 80% full.

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

What happens during atrial contraction?

A

The atrias contract completing the end diastolic volume

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

What does the P wave in the ECG signal?

A

Atrial depolarisation

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

What happens between the P wave and the QRS complex?

A

Atrial contraction

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

What is the end diastolic volume in a resting normal adult?

A

approx .130ml

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

When does ventricular contraction start?

A

After the QRS complex

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

When do the AV valves shut?What does this produce

A

When ventricular pressure exceeds atrial pressureS1

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

Why is phase 3 called isovolumetric ventricular contraction?

A

The tension rises around a closed volume

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

When does the aortic/ pulmonary valves open?

A

When the ventricular pressure exceeds the aortic/ pulmonary pressure

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

What is ejected during ventricular ejection?

A

Stroke volume

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

SV=? (equation + values)

A

SV = EDV - ESV = 135 - 65 = 70ml

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

T wave represents?

A

Ventricular repolarisation

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

When does the aortic/ pulmonary valves shut?What does the produce?

A

When the ventricular pressure falls below aortic/ pulmonary pressureS2

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

What signals the start of isovolumetric ventricular relaxation?

A

Closure of the aortic/ and pulmonary valves

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

Why is stage 5 called isovolumetric ventricular relaxation/

A

The tension falls around a closed box

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

When does the heart start a new cycle?

A

When the ventricular pressure falls below atrial pressure causing the AV valve to open

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

What does S1 signal?

A

The start of systole (closure of mitral and tricuspid valves)

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

What does S2 signal?

A

The end of systole and beginning of diastole (closure of aortic and pulmonary valves)

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

What is the JVP an indirect measure of?How does this work?

A

The pressure in the right atriumThe jugular vein becomes the SVC which connects to the right atrium meaning any changes in the RA will be reflected in the JVP

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

What is the SA node made of?

A

Specialised pacemaker cells

25
Sinus rhythm?
Heart is controlled by the SA node
26
How is an action potential generated?
Cells in the SA node exhibit spontaneous pacemaker potential meaning the membrane potential gradually drifts until it reaches threshold which causes the cell to fire
27
Pacemaker potential?
Gradual drift of the membrane potential towards depolarisation
28
What is the ionic basis of the pacemaker potential?
There is a decrease in K efflux whilst there is slow Na influx
29
What causes depolarisation of the SA node cells?
At threshold, activation of voltage-gated Ca channels occur resulting in Ca influx
30
What is the ionic basis of repolarisation?
Activation of K channels results in K efflux
31
Passage of excitation through the heart path?
SA node -> cell-to-cell conduction -> AV node -> bundle of his -> left and right branches -> purkinje fibres
32
What does cell-to-cell conduction occur via?
Gap junctions
33
What are gap junctions part of?
Intercalated disc which are specialised intracellular attachment between cardiac muscle cells - they are made up of gap junctions, ask adherents and desmosomes
34
Location of the AV node?
Base of the right atria just above the junction of the atria and ventricles
35
How fast is the AV bode conduction velocity?
Fast
36
Resting membrane potential of of contractile muscle cells?
-90mV
37
What causes the rising phase (depolarisation) of the action potential in contractile muscle cells?What does this reverse the membrane potential to?What phase is this?
Fast Na+ influx+30Phase 0
38
What causes phase 1 of ventricular muscle action potential?
Closure of Na+ channels and transient K+ efflux
39
What causes phase 2 of ventricular muscle action potential?what is another name for this phase?
Mainly the influx of Ca through voltage-gated Ca channelsPlateau phase
40
What causes phase 3 of ventricular muscle action potential?
Closure of Ca channels and K efflux
41
What is phase 4?
Resting membrane potential
42
What is the main influence of heart rate/
Autonomic nervous system
43
What is the parasympathetic supply to the hear?
The vagus nerve
44
What type of nerve supply to the SA node dominates under resting conditions
The vagal tone - slows the intrinsic heart rate from approx. 100 to 70bpm
45
Where in the heart does the vagus supply?
The AV and SA nodes
46
What does the vagal nerve stimulation do?
Increases AV nodal delayDecreases heart rate
47
What neurotransmitter does the vagus nerve use to slow the heart?What is a competitive inhibitor of this and can be therefore used to treat extreme bradycardia?
acetlycholine acting through M2 receptorsAtropine
48
How does vagal stimulation affect the pacemaker potential?What happens to the slope of the pacemaker potential?What is the name for this effect
The cell hyper polarises meaning it takes longer to reach threshold, frequency of AP decreases Slope decreasesNegative chronotropic effect
49
Where do cardiac sympathetic nerves supply
AV nodeSA node Myocardium
50
What effects does sympathetic stimulation of the heart have?
Increases heart rateDecreases AV nodal delayIncreases force of contraction
51
Neurotransmitter for sympathetic supply to heart
Noradrenaline acting through B1-adrenoceptors
52
What effect does noradrenaline have on the slope of the pacemaker potential? Speed at which pacemaker potential reaches threshold?Frequency of action potentials? Effect?
Increases slopeIncreasesIncreasesPositive chronotropic effect
53
P wave?
Atrial depolarisation
54
QRS complex
Ventricular depolarisation
55
T wave
Ventricular repolarisation
56
PR interval
Largely AV nodal delay
57
ST segment
Ventricular systole
58
TP interbal
Diastole

1st Year - Cardiology (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions