PSIO 532 Study Guide - Midterm Guide: Turbulence, Hemorheology, Blood Vessel
Graduate Physiology PSL
Laminar Flow Vs. Turbulent Flow
➔ Define resistance and conductance. Understand the effects of adding resistance in series
vs. in parallel on total resistance and flow. Apply this information to solving problems
characterized by a) resistances in series and b) resistances in parallel. Apply this concept
to the redistribution of flow from the aorta to the tissues during exercise
Resistance – the force opposing movement of fluid through a blood vessel based on
properties of the blood vessel size and length and viscosity of the fluid (it is essentially
the force that resists the blood from going through a particular vessel); so if the vessel is
arro, it’s for that lood to get through, resistae is high
Conductance – the ierse of the force opposing movement of fluid through a blood
essel ased o properties of the lood essel size ad legth ad isosity of the fluid
(1/R – conductance) → conductance has been used as a substitute for resistance under
conditions where there is constant perfusion pressure
Resistances in series (artery → arteriole → capillary → venule → vein) are
directly additive and therefore individual resistances can have large influences
on pressure; changes in these individual resistances can have a big impact
eause it’s oe ehid the other; it a ipat hat oes ito the orga
Although total flow is constant at each level in the series, the pressure
decreases progressively as blood flows through each sequential component (you
want to protect the organ from too high of a pressure, which can result in end
organ damage
The majority of resistance to an individual organ is controlled at the level of
the arterioles → the largest pressure drop is at the arterioles; this is because
they provide the biggest resistance
▪ Resistances in parallel reflect that that CO is distributed
on a percent basis among the organs
▪ The effects of this arrangement are that there is no loss
of pressure in the major arteries; small change in resistance
in an individual organ will NOT affect the resistance in other
organs
Mean pressure in each major artery will be approximately
the same as mean pressure in the aorta (lot of the time
people use the mean arterial pressure in the aorta to
calculate the resistance in the individual organ if they have the blood flow for that specific
organ)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Understand the effects of adding resistance in series vs. in parallel on total resistance and flow. Apply this information to solving problems characterized by a) resistances in series and b) resistances in parallel. Apply this concept to the redistribution of flow from the aorta to the tissues during exercise. List the factors that shift laminar flow to turbulent flow. Ideally, blood flow in the exceeds 2000 cardiovascular system is laminar, or streamlined; however, because we have endothelial lining, it causes the blood flow to not streamline perfectly. In turbulent flow, when an irregularity occurs in a blood vessel (e. g. , at the valves or at the site of a blood clot, or endothelial damage), the laminar stream is disrupted and blood flow may become turbulent. Density, diameter, velocity and viscosity are the factors that shift laminar flow to turbulent flow. Reynolds number (nr) < 2000, blood flow will be laminar.
