Learn the differences between these blood vessels! Rishi is a pediatric infectious disease physician and works at Khan Academy. [7:43]

Remember the three key layers of a blood vessel (Tunica intima, Tunica media, and Tunica externa) and how arteries, veins, and capillaries are all different from one another. Rishi is a pediatric infectious disease physician and works at...

This lesson will identify the main structures and function of the cardiovascular system as one of the 11 organ systems of the human body. It is 1 of 2 in the series titled "Cardiovascular System."

A video showing an animation of how the one-way valves in veins work to push blood towards the heart. [0:19]

This lesson will classify the various types of blood vessels depending on their structure and function. It is 1 of 3 in the series titled "Blood Vessels."

Doctors and nurses use IVs to get fluids or medicines directly into a person's vein. IV is short for intravenous. Yes, there's a needle involved - but only for a couple of seconds. [2:14]