Lecture 2: CV Function (Exam I) Flashcards
What is the rapid ejection phase?
When does it occur?
How much stroke volume movement occurs during this phase?
- 1st 1/3 of Ejection Period (Phase III) where 70% of stroke volume (SV) comes from.
What valve(s) would you expect to open/close at the point indicated by 1 in the figure below?
Why?
- A-V valves closure.
- This occurs due to ventricular pressure exceeding atrial pressure.
What valve(s) would you expect to open/close at the point indicated by 2 in the figure below?
Why?
- Aortic valve opening
- This occurs due to ventricular pressure exceeding aortic pressure.
What valve(s) would you expect to open/close at the point indicated by 3 in the figure below?
Why?
- Aortic valve closure
- This occurs due to aortic pressure exceeding ventricular pressure.
What valve(s) would you expect to open/close at the point indicated by 4 in the figure below?
Why?
- AV valves opening.
- This occurs due to atrial pressure exceeding ventricular pressure.
What is normal ESV (End-systolic volume) for A&P?
- 50mLs
What is normal EDV (End-diastolic volume) for A&P?
- 120mLs
In a healthy adult (not acutely ill) at rest, how many mls of blood do the atria contribute to EDV? What is this as a percentage of of SV?
- 10 mls
- 5-10%
In a sick adult, what percentage of Cardiac Output does atrial kick contribute?
- Atrial kick contributes 25-30% in a sick individual.
At what point would one expect all 4 cardiac valves to be closed?
- Beginning of Phase II & IV
What is depicted by graph (a) on the figure below?
- Aortic pressure
What is depicted by graph (b) on the figure below?
- Left atrial pressure
What is depicted by graph (c) on the figure below?
- Left ventricular pressure
What is depicted by graph (d) on the figure below?
- Ventricular volume
What is depicted by graph (e) on the figure below?
- Electrocardiogram
What is depicted by graph (f) on the figure below?
- Phonocardiogram
In the graph depicted below, what valves would you expect to be closed during the time boxed in with the pink box?
- Mitral/Tricuspid valves
In the graph depicted below, What is the importance between 1 & 2 in regards to ventricular volume?
- 1: 70% of SV in first ⅓ of ejection period
- 2: 30% of SV in last ⅔ of ejection period
The diastolic period of the heart is composed completely of the heart filling. T/F
- False: No filling occurs during isovolumetric relaxation.
needs verification
What is the longest phonocardiographic sound?
What does it correlate with?
- 1st sound
- Correlates with AV valves closing
What phonocardiographic sound generally isn’t heard in healthy individuals?
If heard, what is theorized to be the cause of the sound?
- 3rd sound
- Rapid ventricular filling
When does the rapid ventricular filling phase occur? (select all that apply)
a. After the 1st heart sound
b. Before the 2nd heart sound
c. After the 2nd heart sound
d. Before the 3rd heart sound
e. After the 3rd heart sound
- a,c,d
How much blood fills the ventricles during the first ⅓ of the filling phase?
- ~50mls
How much blood fills the ventricles during the second ⅓ of the filling phase?
- ~10mls
How much blood fills the ventricles during the last ⅓ of the filling phase?
- SV - first ⅓ - second ⅓
(ex. if SV = 70 then 70 - 50 - 10 = 10mls)
In what phase do the atria contribute to ventricular filling?
- Phase I (Period of filling) specifically the last ⅓ of the filling phase.
Label the a, c, & v waveforms on the Wiggers diagram below.
What causes an (a) waveform on a Wiggers diagram?
- ↑ CVP due to atrial contraction sending blood into ventricles and backwards.
needs verification
What causes the (c) waveform on a Wiggers diagram?
- Backward “bowing” of the valves (from ventricular contraction) slightly displacing blood backwards.
What causes a (v) waveform on a Wiggers diagram?
- Volume accumulating in the atria until opening of the tricuspid/mitral valves.
Based upon a perfect Wiggers diagram, what electrical activity would correlate with the opening of the AV valves?
- End of the T-Wave.
What is EW? What is it composed of?
- EW is the external work of the heart and is composed of volume & pressure.
What is PSF?
What is a normal PSF?
What two factors compose PSF?
- Mean systemic filling pressure
- 7mmHg
- SVR & total volume
At what right atrial pressure (RAP) would we expect to see venous return plateauing?
- -4mmHg
Increasing PSF to 14mmHg from 7mmHg would have what effect on venous return?
- ↑ Venous Return
Decreasing venous tone and/or decreased venous volume would have what effect on PSF?
- ↓ PSF
What cardiac output (CO) would one expect to see with normal sympathetic stimulation?
What if the patient was exogenously stimulated with catecholamines, what would the max CO be?
- 13L/min
- ~ 25-30L/min
A hypoeffective heart would have a rightward/leftward cardiac output curve shift?
Would baseline right atrial pressure increase or decrease in this scenario?
- Rightward curve shift
- ↑ RAP
A hypereffective heart would have a rightward/leftward cardiac output curve shift?
Would baseline right atrial pressure increase or decrease in this scenario?
- Leftward curve shift
- ↓ RAP
Comparatively, does an increase in contractility or an increase in venous return result in a greater increase in CO?
- Increases in venous return have a greater effect on CO than increases in contractility.
How is SVR calculated?
[(MAP - CVP) ÷ CO] x 80 = SVR
What is Pouseilles equation?
(πΔPr⁴) ÷ 8ηL
What pressure do the aortic baroreceptors respond to in comparison to the carotid baroreceptors?
Aortic baroreceptors function at a pressure 20-30mmHg higher than the carotids.