Peripheral Resistance is a medical term used to describe the resistance in the blood vessels to the flow of blood. The word is commonly pronounced as /pəˈrɪfərəl rɪˈzɪstəns/ where the stress falls on the second syllable of each word. The word peripheral is spelled with an "i" in the second syllable, as opposed to "e," which is a common spelling mistake. The word resistance is spelled as it sounds, with an "a" in the first syllable and "e" in the second syllable.
Peripheral resistance refers to the measure of resistance that is encountered by blood flow as it moves through the blood vessels in the peripheral circulatory system. It is the resistance that the arteries, arterioles, and capillaries offer to the blood flow. This resistance is primarily determined by the diameter of the blood vessels, their elasticity, and the viscosity of the blood.
Peripheral resistance plays a crucial role in regulating blood pressure and ensuring adequate blood flow to different organs and tissues in the body. The resistance offered by the blood vessels determines the pressure required for blood to flow through them. If the peripheral resistance increases, blood pressure can rise, potentially leading to hypertension.
Several factors influence peripheral resistance. One of the key factors is the constriction or relaxation of the smooth muscles in the walls of arterioles, which can affect the diameter of the blood vessels. Other factors include the presence or absence of vasoactive substances like hormones and neurotransmitters, blood volume, and blood viscosity.
Measurement of peripheral resistance is often used in clinical settings to assess vascular health. Techniques like measuring blood pressure and calculating systemic vascular resistance are commonly employed to evaluate the resistance encountered by blood flow in the peripheral circulatory system.
In summary, peripheral resistance refers to the resistance offered by blood vessels to blood flow in the peripheral circulatory system. It is a critical determinant of blood pressure and plays a vital role in regulating blood flow to various organs and tissues in the body.
The word "peripheral" comes from the Latin word "peripheria", which means "circumference" or "the outer regions". It is derived from the Greek word "periphereia", which also means "circumference" or "surrounding".
The word "resistance" ultimately comes from the Latin word "resistere", which means "to withstand" or "to oppose". It is derived from the combination of the prefix "re-", meaning "back" or "against", and the verb "sistere", meaning "to stand" or "to stop".
When combined, "peripheral resistance" refers to the resistance or opposition encountered by blood flow in the peripheral (outer) regions of the body, particularly in the small blood vessels called capillaries.