Haemodynamic Concepts Flashcards
What is the Continuity Principle?
states that the volume of fluid passing through a vessel must remain constant. In the context of blood flow, this means if a vessel narrows (like in stenosis), the velocity of blood must increase to maintain the same flow rate. It’s why we get faster blood flow at constricted points.
What is Bernoulli’s Principle?
states that an increase in the speed of fluid occurs simultaneously with a decrease in pressure
What is Poiseuille’s Law in ultrasound?
describes how the flow rate of a fluid is determined by the viscosity of the fluid, the length and radius of the vessel, and the pressure gradient
Describe Laminar flow
a smooth, orderly flow of blood, where layers of fluid slide over one another with minimal mixing
Describe turbulent flow
chaotic and often seen in areas of stenosis or other abnormalities
What is Disturbed flow ?
an irregular pattern of blood movement, often occurring at branch points, curves, or in mildly narrowed vessels
Describe Arterial resistance
refers to the opposition to blood flow within the arteries, which can be assessed using Doppler ultrasound
What happens during Systole?
heart contracts. Blood is ejected from the left ventricle into the aorta and subsequently into the arteries, providing the pressure needed to drive blood through the peripheral circulatory system.
What happens during Diastole?
heart relaxes, allowing the chambers to fill with blood. This relaxation helps maintain continuous blood flow.
What is Peripheral Resistance ?
the opposition to blood flow in the circulatory system, primarily determined by vessel diameter and blood viscosity. Increased peripheral resistance can result from conditions like hypertension, where arterioles constrict, leading to higher blood pressure and increased workload on the heart.
