Lecture #6 Hemodynamics: Pressure, Flow, and Resistance Flashcards
What is Hemodynamics?
Is the study of fluid flow in the vascular system–and fluid always flows from high pressure to regions of lower pressure
What is resistance?
Fluid flow is caused by friction between the molecules in the fluid and the walls of the tube (Friction resistance ALWAYS reduces flow)
What are the determinants of Blood Pressure?
Not equal throughout the cardiovascular system—if it were then blood would not flow because it requires pressure difference (driving pressure)
Blood pressure is ____ and in phase with the heartbeat.
Pulsatile
When does blood pressure peak?
During systole and falls during diastole
What is the estimating mean of blood pressure equation?
MAP = DBP + 1/3 (SBP - DBP)
What factors does the arteries close to the heart?
Arterial elasticity (compliance or distensibility)
Amount of blood forced into them at any given time
What is arterial compliance?
Large arteries are very compliant. High compliance and elasticity allows the flow to be propelled throughout the cardiac cycle, owing to the alternating expansion and recoil of the arteries after each contraction of the left ventricle.
What is the compliance equation?
C = dV/dP
Generates a pressure waved called the _____.
Pulse
What is the pulse pressure?
PP= SBP - DBP
reflects stroke volym if C is constant
(C = dV /dP ) dV = C x dPP
Are stiff arteries more compliant or less compliant?
Less compliant—to maintain same volume the pressure must increase so hypertension associated with stiff arteries.
Is the pressure higher or lower in the pulmonary circuit than systemic circulation?
Lower than those in the systemic circulation.
Is pulmonary circulation lower or highly compliant?
Highly compliant
What is the mean pressure in the pulmonary artery?
14 mmHg at rest
