Lecture 22: Circulation and Hemodynamics Part II Flashcards
What are the two types of pressure found in capillary wall that deal with moving fluids in and out of vessels?
Hydrostatic Pressure
Osmotic Pressure
What do hydrostatic pressures deal with?
Pushing fluid out
What do osmotic pressures deal with?
Pulling fluid out
What is Starling Equation?
Jv = Kf[(Pc - Pi) - (πc - πi)
If the Starling equation gives a positive value, what does that mean?
Net movement of fluid leaving capillary
If the Starling equation gives a negative value, what does that mean?
Net movement of fluid entering capillary
Heart failure can change what part of the Starling equation?
Pc
Restricted lymphatic flow can change what part of the Starling equation?
Pi
πi
Decrease in albumin can change what part of the Starling equation?
πc
Inflammation can change what part of the Starling equation?
πi
If blood pressure is elevated, what happens to the arterial walls under myogenic control?
Vasoconstriction
-tries to limit blood entering and prevent stretching of arterial walls
What is active hyperemia?
Increase in blood flow
- due to increase of metabolites
- reduction of oxygen
What is reactive hyperemia?
Increase in blood flow that occurs following a brief period of ischemia
-Sitting on hand for long period of time and then allowing a bunch of blood to enter after hand is free
What is shear?
Stress on arterial walls due to increase in blood flow
-the increase shear stress can cause release of NO and further cause more vasodilation
Does histamine and bradykinin cause vasodilation or vasoconstriction?
Vasodilation
Does serotonin cause vasodilation or vasoconstriction?
Vasoconstriction
Coronary and cerebral circulation is largely under what control?
Metabolic control
-don’t want coronary flow to vasoconstrict when SNS is active
Where are the highest pressures of the pulmonary vascular system found?
Right ventricle
Pulmonary artery
Why is there vasoconstriction when there is alveolar hypoxia?
Don’t want to increase blood flow to parts of lungs that do not properly work
Why does the pulmonary blood flow have significantly less pressure and resistance compared to systemic circulation?
Pulmonary vasculature much more complaint
- easier to dilate arteries
- easier to reduce resistance
How does the shunt pathway help vasculature in skin?
Helps remove heat and metabolic waste from skin
What is the right to left shunt?
Systemic veins –> systemic arteries
- does not pass functional lung tissue
- example: fetus blood goes from RV to LV
What is the left to right shunt?
Systemic arteries –> systemic veins
- does not pass functional lung tissue
- example: skin
