If you're seeing this message, it means we're having trouble loading external resources for Khan Academy.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Pressure Volume Loops

12 videos
The pressure volume loop is one of the classic figures that helps us to conceptualize and understand the mechanics of the left ventricle of the heart. In addition to a filling up with blood and squeezing out blood there is a (very short) period of time when the heart muscle is contracting and relaxing with no volume change! As the left ventricle moves around the PV loop with each lub dub you get a sense for the amazing amount of work it does as pressures and volumes go up and down, all day, every day. This is a fascinating area where physics and biology meet to produce something miraculous.

Pressure in the left heart - part 1

VIDEO 14:59 minutes
Watch the pressure in the left heart go up and down with every heart beat! Rishi is a pediatric infectious disease physician and works at Khan Academy.

Pressure in the left heart - part 2

VIDEO 12:44 minutes
Watch the pressure in the left heart go up and down with every heart beat! Rishi is a pediatric infectious disease physician and works at Khan Academy.

Pressure in the left heart - part 3

VIDEO 13:02 minutes
Watch the pressure in the left heart go up and down with every heart beat! Rishi is a pediatric infectious disease physician and works at Khan Academy.

Left ventricular pressure vs. time

VIDEO 10:51 minutes
Ever wonder exactly how the left ventricle's pressure changes over time? Find out in this color-coded video! Rishi is a pediatric infectious disease physician and works at Khan Academy.

Left ventricular volume vs. time

VIDEO 9:01 minutes
Left ventricular volume changes over time in a way that makes a curious looking graph. Learn more in this video! Rishi is a pediatric infectious disease physician and works at Khan Academy.

Drawing a pressure-volume loop

VIDEO 9:04 minutes
Use the left ventricular pressure and volume information to put together a cool new graph. Rishi is a pediatric infectious disease physician and works at Khan Academy.

Understanding the pressure-volume loop

VIDEO 9:18 minutes
Figure out how all of those physiology terms: end-systolic, end-diastolic, pulse pressure, stroke volume, and ejection fraction, can be easily figured out using the pressure-volume loop. Rishi is a pediatric infectious disease physician ...

End diastolic pressure-volume relationship (EDPVR)

VIDEO 9:58 minutes
Find out what happens when the left ventricle is not allowed to contract, and instead you simply add and take away blood from it. Rishi is a pediatric infectious disease physician and works at Khan Academy.

End systolic pressure-volume relationship (ESPVR)

VIDEO 10:23 minutes
Find out what happens when the left ventricle is not allowed to relax, and instead you simply add and take away blood from it. Rishi is a pediatric infectious disease physician and works at Khan Academy.

Reimagine the pressure volume relationship

VIDEO 13:38 minutes
Understand what is happening at the cellular level to cause two identical left ventricular volumes to have such different pressures! Rishi is a pediatric infectious disease physician and works at Khan Academy.

What is preload?

VIDEO 13:33 minutes
Some say Preload = End-Diastolic Pressure, others say Preload = End-Diastolic Volume, so which one is it? Watch and find out! Rishi is a pediatric infectious disease physician and works at Khan Academy.

Why doesn't the heart rip?

VIDEO 10:26 minutes
Understand LaPlace's law to see the effect that pressure, radius, and wall thickness each have on the "wall stress" in the left ventricle. Rishi is a pediatric infectious disease physician and works at Khan Academy.