Peripheral resistance is inversely proportional to:

(Radius): Ref: 470, 488, 474-SL (542- Ganong 23rd)Peripheral Resistance: - Resistance is the friction or tension or hindrance, against which the blood flows:* It is remarkable in the peripheral vessels particularly the arterioles* Three important factors, which determine the peripheral resistance are:A. Radius of blood vesselsB. Pressure gradientC. Viscosity of bloodResistance =Pressure gradient-------------Volume of blood flow=P1-P2---QPeripheral resistance in inversely related to the radius of the blood vessels i.e., lesser the radius, more will be resistance. The radius of the arterioles is very less because of the sympathetic tone. The arterioles remain partially constricted all the time because of the symphatic tone. So the resistance is more here. The arterioles are known as resistant vessels because of this reason.1. The volume of blood flow is inversely proportional to the resistance2. The volume of blood flow is inversely proportional to the viscosity of blood3. The volume of blood flow is directly proportional to the diameter4. The diastolic blood pressure is directly proportion to peripheral resistance