Brainscape's Knowledge GenomeTM

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


See full index

2.6 BRS Cardiovascular & Respiratory > Cardiac Cycle > Flashcards

Cardiac Cycle Flashcards

1
Q

What is diastole?

A

Ventricular relaxation
- 2/3 beat (0.5 secs)
- 4 phases —> atrial systole (—> 3 of systole)
—> isovolumetric relaxation
—> rapid passive filling
—> slow passive filling

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

What is systole?

A

Ventricular contraction
- 1/3 beat (0.3 secs)
- 3 phases —> isovolumetric contraction
—> rapid ejection
—> slow filling

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

What are the 7 phases of the cardiac cycle?

A
  1. Atrial systole
  2. Isovolumetric contraction
  3. Rapid ejection
  4. Slow filling
  5. Isovolumetric relaxation
  6. Rapid passive filling
  7. Slow passive filling
    - takes 800ms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is end diastolic volume?

A

Blood volume in ventricle before ejection
- around 120ml
- stroke volume = end-diastolic volume - end-
systolic volume

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

What is end systolic volume?

A

Blood volume ejected into arteries
- around 50ml
- stroke volume = end-diastolic volume - end-
systolic volume

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

What is the ejection fraction?

A

ejection fraction = (stroke volume / end-diastolic
volume) x 100
- proportion of blood that leaves the ventricles
- normal: 52-72% (average: 58%)
athletes —> inc
disorder —> dec

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

What is atrial systole?

A

Heart:
- atria —> almost full from passive filling
—> contract and push blood to ventricles

Blood:
- atria —> ventricles

Pressures:
- atrial —> inc
- ventricular —> inc

Valves:
- mitral —> open
- tricuspid —> open
- aortic —> closed
- pulmonary —> closed

ECG:
- P-wave

Heart Sound:
- congestive heart failure/ pulmonary embolism/
tricuspid incompetence —> S4

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

What is isovolumetric contraction?

A

Heart:
- ventricles —> isometric contraction

Pressures:
- ventricular —> inc
- above atria —> AV valves close
- aorta —> stays the same

Valves:
- mitral —> closed
- tricuspid —> closed
- aortic —> closed
- pulmonary —> closed

ECG:
- QRS —> start of ventricular depolarisation

Heart Sound:
- S1 - lub
- AV valves close

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

What is rapid ejection?

A

Heart:
- ventriclular systole —> contract and push blood to
arteries (isotonic contraction)

Blood:
- ventricles —> arteries

Pressures:
- ventricular —> inc
- above arteries —> a/p valve opens
- aorta —> inc

Valves:
- mitral —> closed
- tricuspid —> closed
- aortic —> open
- pulmonary —> open

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

What is reduced ejection?

A

Heart:
- end of systole

Blood:
- ventricles —> arteries

Pressures:
- ventricular —> dec
- aorta —> dec

Valves:
- mitral —> closed
- tricuspid —> closed
- aortic —> start closing
- pulmonary —> start closing

ECG:
- T —> ventricular muscle cells repolarise

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

What is isovolumetric relaxation?

A

Heart:
- ventricles —> relax

Pressures:
- atrial —> gradual rise
- ventricular —> steep dec
- goes below arteries —> a/p valves close
- aorta —> small rise (elastic recoil) - dichotic notch

Valves:
- mitral —> closed
- tricuspid —> closed
- aortic —> closed
- pulmonary —> closed

Heart Sound:
- S2 - dub
- aortic and pulmonary valves close

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

What is rapid passive filling?

A

Heart:
- atria —> blood flows to ventricles
- ventricles —> start to fill

Blood:
- atria —> ventricles

Pressures:
- atrial —> dec
- above ventricles —> AV valves open
- ventricular —> dec
- aorta —> gradual dec

Valves:
- mitral —> open
- tricuspid —> open
- aortic —> closed
- pulmonary —> closed

ECG:
- flat - isoelectric

Heart Sound:
- severe hypertension/mitral incompetence —>
turbulent ventricular filling —> S3 (galloping)

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

What is reduced passive filling?

A

Heart:
- atria —> less blood out to ventricles
- ventricles —> fills up slower (diastasis)

Blood:
- atria —> ventricles

Pressures:
- atrial —> v. gradual inc
- ventricular —> v. gradual inc
- aorta —> gradual dec (blood leaving)

Valves:
- mitral —> open
- tricuspid —> open
- aortic —> closed
- pulmonary —> closed

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

What are the waves of an ECG?

A

P —> atrial systole
- atrial depolarisation
QRS —> isovolumetric contraction
- start of ventricular depolarisation
T —> reduced ejection
- ventricular repolarisation

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

What are the heart sounds?

A

Normal:
S1 —> isovolumetric contraction
- AV valves close
- lub
S2 —> isovolumetric relaxation
- aortic and pulmonary valves close
- dub

Abnormal:
S3 - severe hypertension/mitral incompetence
- turbulent ventricular filling (galloping)
—> rapid passive filling
S4 - congestive heart failure/ pulmonary embolism/
tricuspid incompetence
—> atrial systole

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

What is the difference between the pressure changes in the right and left ventricle?

A

Identical change but right < left
- Left —> reaches 120/80 mmHg
- same vol to higher pressure circuit (systemic)
Right —> reaches 25/5 mmHg
- same vol to lower pressure circuit
(pulmonary)
- both fill to around 120 ml —> eject around 80 ml

17
Q

What are pressure volume loops?

A

Graphs of left ventricular volume (x) against pressure (y) throughout the cardiac cycle
- bread slice shape

18
Q

What do the 4 corners of a pressure volume loop represent?

A
  1. Bottom right (A) —> mitral valve close
    - preload (end-diastolic volume)
    - preload
  2. Top right (B) —> aortic valve close
    - afterload (aortic pressure
    encountered)
  3. Top left (C) —> aortic valve opens
    - end-systolic volume
  4. Bottom left (D) —> mitral valve opens
    - ventricle starts filling
    - A - D = stroke volume
19
Q

What do the 4 sides of a pressure volume loop represent?

A
  1. Bottom - D —> A
    - ventricles filling
  2. Right - A —> B
    - isovolumetric contraction
  3. Top - B —> C
    - ventricles emptying (ejection)
  4. Left - C —> D
    - isovolumetric relaxation
20
Q

Where are preload and afterload represented on a pressure volume loop?

A

Preload - bottom left corner (A)
—> ventricle filled —> max stretch before
contraction
Afterload - top right corner (C)
—> aorta filled —> pressure ventricles must
contract against

21
Q

What is the ESPVR line?

A

End-Systolic Pressure Volume Relationship line
= line for the maximal pressure that can be exerted by
the ventricle at any given volume
—> tangent of active force curve
—> crosses top left corner (C)
- active force (myofilament force) —> through C
passive force (myocyte recoil) —> along AD line

22
Q

How does preload affect a pressure volume loop?

A

Stretched right
- A and B more right
∴ AD and BC line longer
- inc preload —> inc blood volume entering ventricles

23
Q

How does afterload affect a pressure volume loop?

A

Taller and thinner
- C and D to right
B and C up
∴ AD and BC line shorter
AB and CD line longer
- inc afterload —> inc pressure to open aortic valve
—> harder to contract —> dec vol out

24
Q

How do you calculate cardiac output?

A

Cardiac Output = Heart Rate x Stroke Volume

25
Q

Which 3 factors affect stroke volume?

A
  1. Preload
  2. Afterload
  3. Contractility = strength of contraction
26
Q

How is contractility increased?

A

Sympathetic stimulation
1. Inc NA (nervous)/adrenaline (hormonal) released
2. Inc NA/adrenaline binding to β-1 and β-2 adrenergic
receptors (Gs receptors)
3. Inc ATP —> cAMP via adenylyl cyclase
4. Inc cAMP —> PKA
5. Inc phosphorylation of
- L-type Ca2+ channels
- SR Ca2+ release channel
- SR Ca2+ ATPase
—> inc Ca2+ to myofilaments —> inc contractility

27
Q

How does exercise affect the pressure volume loop?

A

Wider and taller —> ESPVR line steeper
1. Inc contractility - via sympathetic activation
—> inc end-systolic volume
2. Inc venous return - via Frank-Starling
—> inc end-diastolic volume
+ inc afterload - via arterial pressure
- offset by inc contractility
+ v. high HR - dec filling time —> dec end-diastolic vol

28
Q

How does contractility affect the ESPVR line?

A

Inc gradient —> above C

2.6 BRS Cardiovascular & Respiratory (15 decks)

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