If you're seeing this message, it means we're having trouble loading external resources on our website.
If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.
Unit 3: Circulatory system diseases
About this unit
With the heart pumping 24/7, it’s crucial that things flow smoothly (pun intended!). Unfortunately, this isn’t always the case. The underlying reasons for circulatory system problems vary from your genes to your lifestyle. To combat this growing problem in the world, we need a better understanding of these diseases.