Cardiovascular Systems 3 - Cardiovascular Mechanics 2 Flashcards

(44 cards)

1
Q

What are the two main phases of the heart, and what proportion of the heart beat do they take up?

A
  • Diastole is the relaxation of the ventricle, which is split into 4 distinct phases
  • Systole is the contraction of the ventricle, which is split into 3 phases.
  • Diastole is 2/3 of the heartbeat, and systole is 1/3.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

List the 3 phases of systole.

A
  • Isovolumetric contraction
  • Rapid ejection
  • Slow ejection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

List the 4 phases of diastole.

A
  • Isovolumetric relaxation
  • Rapid passive filling
  • Slow passive filling
  • Atrial systole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How can the stroke volume be calculated?

A

End diastolic volume - end systolic volume

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

How can the ejection fraction be calculated?

A

Stoke volume / end diastolic volume x 100

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

Describe the process of atrial systole.

A
  • The P wave on an ECG signifies the start of the heartbeat
  • The ventricles are already filling slowly via movement of blood down its pressure gradient. To finish vetricular filling, there is contraction of the atria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When is the 4th heart sound heard?

A

When there is arterial stenosis, resulting in a greatly thickened ventricular wall.

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

Describe the process that occurs in isovolumetric contraction.

A
  • This is where the ventricle is contracting and pressure is increasing but there is no change in volume, as the pressure must be high enough to open the aortic valve/pulmonary valve.
  • Accompanied by the QRS complex - signifying ventricular depolarisation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What causes the first heart sound (lub)?

A

The AV valve closing due to increasing ventricular pressure.

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

What happens during rapid ejection?

A
  • The aortic and pulmonary valves open at this stage

- He volume in the ventricles decreases

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

What happens during reduced ejection?

A
  • End of systole
  • There is a reduced pressure gradient, so the pulmonary and aortic valves start to close. Blood leaving the ventricle slows. Finally, the valves fully close.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens during isovolumetric relaxation?

A
  • All valves are shut

- There is no change in ventricular volume, but the pressure decreases. Atrial pressure increases as blood flows in.

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

What does the T wave signify?

A

Ventricular depolarisation

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

What causes the second heart sound?

A

Closing of the semilunar valves

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

What happens in rapid passive filling?

A
  • The pressure in the atria overcomes that in the ventricle, so the AV node opens.
  • Blood flows into the ventricles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What causes the third heart sound?

A
  • Usually abnormal - turbulent ventricular filling

- Due to hypertension or mitral incompetence

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

What is another name for reduced passive filling?

A

Diastasis

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

What occurs in reduced passive filling?

A
  • The ventricle fills slowly without contraction of the atria.
  • This is the longest phase.
19
Q

How similar are the pressures in the left and right heart?

A
  • Pressures in the right heart are lower
  • Patterns of pressure changes are different
  • Right ventricle ejects the same volume of blood as the left.
20
Q

What is the pressure in the systemic circuit?

21
Q

What is the pressure in the pulmonary circuit?

22
Q

What is the axis on a pressure volume loop?

A

Volume (x) and pressure (y)

23
Q

What is the point A on a pressure volume loop?

A
  • Mitral valve closes

- End diastolic volume, meaning it represents the preload

24
Q

What is the point B on a pressure volume loop?

A
  • Aortic valve opens

- Diastolic blood pressure

25
What is point C on a pressure volume loop?
- End systolic volume | - Aortic valve closes (lub)
26
What is point D on a pressure volume loop?
- Mitral valve opens
27
What is the line A to B on a pressure volume loop?
Isovolumetric contraction
28
What is the line B to C on a pressure volume loop?
Ejection
29
What is the line D to C on a pressure volume loop?
Isovolmetric relaxation
30
What is the line D to A on a pressure volume loop?
FIlling
31
Where is the end diastolic PV line on a pressure volume loop and what does it denote?
- Passes from A to D and beyond | - The end diastolic PV line denotes elastance (preload)
32
Where is the end systolic PV line on a pressure volume loop?
- Passes through C | - Denotes contractility
33
Where is the afterload line on a pressure volume loop?
From C through the highest ventricular volume on the x axis.
34
Which section of the PV loop is longest?
D to A
35
How is ejection fraction calculated from a PV loop?
(volA - volD)/volA
36
How is mean arterial pressure calculated from a PV loop?
PressureB + 1/3(PressureC-PressureB)
37
How is pulse pressure calculated on a PV loop?
Pressure C - Pressure B
38
How is cardiac output measured on a PV loop?
(VolA - VolB) x Heart Rate (67)
39
How can you calculate stroke volume?
Volume A to B - Volume C to D
40
How do increases in preload affect the pressure volume loop?
- Increase in stroke volume | - Line A B moves to the right (increased volume)
41
Hoe do increases in afterload affect the pressure volume loop?
- Decreased stroke volume, but an increased pressure - Line C D moves to the right (increased volume) - Line D A moves upwards (increased pressure)
42
What factors affect stroke volume?
- Preload - Afterload - Contractility
43
What is contractility?
- The capability of the heart to contract | - Measured by ejection fraction
44
What is the dicrotic notch?
A small rise in aortic pressure when the aortic valve closes