Brainscape's Knowledge GenomeTM

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


See full index

Cardiovascular System > S4 Cardiac Cycle > Flashcards

S4 Cardiac Cycle Flashcards

1
Q

What are the key structures of theLeft side of the Heart.

A 
Pulmonary veins
Left atrium
Mitral valve
Left ventricle
Aortic valve
Aorta
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the key structures of the Right side of the Heart.

A 
Superior Vena Cava 
Inferior Vena Cava
Right atrium 
Tricuspid valve
Right ventricle
Pulmonary valve
Pulmonary artery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define systole

A

Contraction and ejection of blood from ventricles

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

Define diastole

A

Relaxation and filling of ventricles

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

What is the stroke volume of the heart? (Inc. volume)

A

Stroke volume in the amount of blood ejected from the ventricle per beat.

Approx 70ml per beat

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

What is the average Heart rate?

A

Between 60-100

At 70bpm 4.9l of blood pumped per minute (approx the amount in the body)

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

What are the four valves and how do they open or close?

A

Right- tricuspid, pulmonary valves
Left- mitral valve, aortic valve.

They open/close by differential pressures.

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

How are Mitral and tricuspid valves linked to the heart?

A

They are attached to papillary muscles via the chordae tendonae which prevents inversion during systole.

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

What is the hearts pacemaker?

A

The sinoatrial node

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

Describe the Heart’s conduction system.

A

Action potential generated by the SAN.
Spreads over The atria (atrial systole)
Reaches the Atrioventricular node and is delayed for 120ms
AVN spreads the excitation down the septum via the Purkinje fibres which spread through the ventricular myocardium from inner (endocardial) to outer (epicardium) surface
Ventricles contact from the apex up forcing the blood up through the up flow valves.

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

What are the 7 phases of the cardiac cycle.

A 
1 - Atrial contraction 
2 - Isovolumetric contraction
3 - Rapid ejection
4 - Reduced ejection
5 - Isovolumetric relaxation
6 - Rapid filling
7 - Reduced filling

repeat

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

What is a Wiggers diagram?

A

A diagram showing the events of the cardiac cycle through pressure changes (mmHg) and volume (ml).

Typically in the Left side of the heart.

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

Describe phase 1 of the cardiac cycle.

A

Atrial contraction.

Atrial pressure rise called “A wave”
Accounts for the final 10% of ventricular filling
P wave of ECG signifies onset of atrial depolarisation.

At the end of Phase one ventricle volumes are maximal termed the End-diastolic volume (EDV) ~120ml

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

Describe Phase 2 of the cardiac cycle.

A

Isovolumetric contraction.

Mitral valve closes as pressure in ventricles>atria
Rapid rise in ventricular pressure as their contract
Closing of Mitral valve causes “C wave” in atrial pressure curve.
Isovolumetric as no change in ventricular volume and valves are shut.
QRS wave in ECG signifies onset of ventricular systole.
Closure of heart signifies first heart sound (S1)

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

Describe Phase 3 of the cardiac cycle.

A

Rapid ejection.

As pressure in ventricle>aorta, aortic valve OPENS to allow ejection to begin.
Atrial pressure decreases called an “X descent”
Rapid blood decrease in ventricular volume as blood enters aorta.

Blood continues to flow into the atria from veins.

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

Describe Phase 4 of the Cardiac cycle.

A

Reduced ejection.

Repolarisation of ventricles, decline in tension and rate of ejection falls.
Atrial pressure gradually increases due to venous return, called “V wave”
Ventricular repolarisation shown by T wave on ECG

17
Q

Describe Phase 5 of the Cardiac cycle

A

Isovolumetric relaxation

When ventricular pressure

18
Q

Describe Phase 6 of the Cardiac cycle.

A

Rapid filling.

Fall in atrial pressure after opening of mitral valve called “Y descent”
Intraventricular pressure falls below atrial pressure
Mitral valve opens ventricles begin to fill ( volume increases)

Ventricular filling is usually silent but can be present (S3).
S3 normal in children but can be a sign of pathology in adults.

19
Q

Describe Phase 7 of the Cardiac cycle.

A

Reduced filling.

Rate of filling slows down (diastole) as ventricles reach the inherent relaxed volume. Further filler is driven by venous pressure.
Ventricles 90% full at the end of Phase 7

20
Q

What is Stenosis?

A

Valve doesn’t open enough

Obstruction to blood flow when valve normally opens

21
Q

What is regurgitation?

A

Incompetence/Insufficiency

Valve doesn’t close all the way
Back leakage when valve should be closed.

22
Q

What causes Aortic valve stenosis?

A

Degenerative - senile calcification or fibrosis
Congenital - bicuspid form of valve
Chronic rheumatic fever - inflammation, commiserate fusion.

23
Q

What are the possible consequences of aortic stenosis?

A

Path 1
Less blood through valve - increase LV pressure ->LV hypertrophy
Less blood through valve - left sided heart failure -> syncope or angina.

Path 2
Shear stress - microangiopathic haemolytic anaemia

24
Q

What causes aortic valve regurgitation?

A

Aortic root dilation (leaflets pulled apart)

Valvular damage (edocharditis rheumatic fever)

25
Q

What are the consequences of aortic valve regurgitation?

A

Blood flows back into LV during diastole.
Increase SV
Systolic pressure increases
Diastolic pressure decreases
Bounding pulse (head bobbing, Quinke’s sign)
LV hypertrophy.

26
Q

What causes mitral valve regurgitation?

A

Myxomatous degeneration can weaken papillary muscle and chordae tendonae causing a prolapse in systole.

Damage to papillary muscle following an MI

Left sided heart failure leads to LV dilation which can stretch valve.

Rheumatic fever can lead to leaflet fibrosis which disrupts seal formation.

27
Q

What are the consequences of mitral regurgitation?

A

Some blood leaks back into LA which increases preload as more blood enters LV in subsequent cycles… can cause LV hypertrophy.

Causes a holosystolic murmur.

28
Q

What causes Mitral valve stenosis?

A

Mainly Rheumatic fever (~99.9% of cases.)

Commissural fusion of valve leaflets.

Harder blood flow from LA to LV

29
Q

What are the consequences of Mitral Valve stenosis?

A

Increased LA pressure - Pulmonary oedema/Dyspnea/pulmonary hypertension —> RV hypertrophy

Increased LA pressure - LA dilation —> atrial fibrillation —> Thrombus formation

Increased LA pressure - LA dilation —> oesophageal compression—> dysphagia

30
Q

What changes occur to systole and diastole if the heart rate is increased?

A

Systole stays the same,

Diastole decreases.

Cardiovascular System (3 decks)

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