How does blood flow through your blood vessels?

• A. GCS (Glasgow Coma Scale)
• B. Hemodynamics
• C. EKG (Electrocardiogram)
• D. Pan Scan

Answer: (B)

Understanding how blood moves through the circulation is a study in hemodynamics. Hemodynamics describes the forces and motions of blood – how pressure differences drive flow, and how the vessels’ resistance shapes that flow. The heart creates a pressure gradient: blood is pumped into the arteries at higher pressure and returns through veins where the pressure is lower. Blood will travel from high to low pressure, and how easily it flows depends on resistance inside the vessels. That resistance is largely determined by vessel radius: a small change in radius makes a big difference in flow because resistance changes with the fourth power of radius. Factors like blood viscosity and vessel length also play a role. The heart’s output and the vessels’ resistance work together to meet the body's needs, with local regulation adjusting flow to tissues as needed.

The other terms don’t describe this process. A Glasgow Coma Scale measures consciousness level, an EKG records the heart’s electrical activity, and a Pan Scan is a comprehensive CT imaging study. Only hemodyamics directly explain how blood moves through blood vessels.