1.03 Hemodynamics.

Cardiovacular system reveiw for the USMLE Step 1 exam.

• Hemodynamics studies blood flow through the body
• Volumetric flow rate (Q) describes the volume of material moving through space per unit time, in terms of psychiatry it is the amount of blood moving through a vessel per unit time
• Volumetric flow rate is proportional to radius to the 4th power, so when radius increases, volumetric flow rate increases
• Resistance is a measure of a blood vessel's opposition to blood flow
• Resistance is inversely proportional to radius to the 4th power, so when vessel radius is increased, resistance decreases
• For vessels in series, you can simply add the resistances of each up to get the total resistance
• For vessels in parallel, the total resistance is equal to the sum of the inverses of the resistances each vessel