Class notes
Cardiovascular System 4: Cardiac Cycle
- Course
- Institution
A detailed summary of the cardiac cycle and the law of laplace.
[Show more]
Seller
Follow
harrykane
Reviews received
Content preview
CARDIAC CYCLE1. Ventricular filling from IVC and SVC.
2. Atrial systole – atria contract when pressure in atria is greater than ventricles (P-R
waves).
3. Isovolumetric contraction – AV valves shut, S1 heart sound, QRS complex.
4. Ejection phase – ST segment, semi-lunar valves open, as pressure in ventricles is
greater than atria.
5. Isovolumetric relaxation – just after T phase, ventricles relax and atria start filling S2
heart sound as semi-lunar valves shut.
Normal Blood Pressure – 120/80mmHg.
In left ventricle, the blood pressure is 117/1mmHg but diastolic
pressure maintained above 1 by Windkessel effect.
Area within the cardiac cycle loop is the work of the heart.
Area within the loop for a Right Ventricle will be smaller than a
Left Ventricle.
A = Mitral valve opens.
A-B = Rapid filling of ventricle (ventricle relaxation).
B-C = Slower filling of the ventricle.
C = Atria contract and mitral valve closes.
C-D = Isovolumetric contraction.
D = Aortic valve opens when left ventricle pressure is greater than
aortic blood pressure.
D-E = Rapid ejection.
E-F = Reduced ejection.
F = Aortic valve closes.
F-A = Isovolumetric relaxation which leads to mitral valve opening.
INCREASED PRELOAD
Cardiac cycle loop moves left and increases in width (represents an increase in
stroke volume).
Increase in area of the loop, which increases the cardiac work.
INCREASED AFTERLOAD
Cardiac cycle increases in height and narrower (represents a decrease in stroke
volume).
The height increase means that the load has to get to a higher pressure for the
blood to be ejected.
Less emptying – therefore, heart is larger at the end of systole.
Increase in area of cardiac cycle loop as the heart has to work harder to get rid of
blood due to increase in blood pressure.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller harrykane. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.90. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
64438 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now