This video describes how the circulatory system works, how disease can affect blood vessels (atherosclerosis), and how doctors use angiography to test for coronary artery blockage.

Sometimes used interchangeably, coronary angioplasty and stenting are actually two separate procedures. This video shows how coronary angioplasty and stenting are performed and how the two procedures differ.

This video combines animation and real footage of the heart to demonstrate how the atrial, pulmonic, mitral, and tricuspid valves of the heart work. The coordinated opening and closing of these valves is what allows the heart to provide blood flow and pressure in one direction, toward the lungs and body.

Normal Pressure Hydrocephalus or NPH is described in this animation showing the ventricles of the brain and the flow of cerebrospinal fluid or CSF. The cause is not precisely known but can caused nausea, vomiting, headache, and problems walking among other symptoms.