Flow Through Tubes Flashcards
What is the definition of velocity?
The rate of movement of fluid particles along a tube
What drives the flow of blood?
The pressure gradient
What is laminar flow?
Flow where the gradient of velocity is from the middle to the edge of a vessel
What is turbulent flow?
Where the velocity gradient breaks down and the fluid tumbles over one another
What is viscosity of fluid in relation to one another?
The extent to which fluid resists flowing over one another
What are the two causes of hypervisscocity syndrome?
Abnormally high plamsa protein levels, abnormally high rbc or wbc count
How do the resistances of vessels in parallel interact?
Resistances in parallel are the sum of the reciprocals of the resistances of the individual vessels
How do the resistances of vessles in series interact with one another?
They add to one another
What are the two factors affecting the velocity of a tube?
Mean velocity of inversely proportional to viscosity and directly proportional to the cross sectional area
What is flow according to Posielles law?
Proportional to the 4th power of the radius, inversley proportional to the length of the vessel, inversely proportional to the viscosity o fte blood.
Why do capilleries not have a high collective resistanc?
As they are arranged in parallel
What are some of the causes of tubrulent blood flow?
When flow is high, the lumen of vessels in irregular (such as due to formation of artheroscelortic plaues) and the viscosity of the blood is low.
What are some of the special features of blood flow in vessels?
Distensible vessels which stretches to allow the resistance of the vessels to lower and acts as a storage vessel for the blood
In what cases can you hear turbulent flow in blood vessels?
Can be heard on auscultation of the renal arterys, can be heard in artheroscelortic blockages in the hetpric artery, the femoral artery and the carotid artery.
What is the definition of flow?
Volume of fluid passing a point per unit time
