Advanced pathpharm week 5 Flashcards
Define the term hemodynamics in relation to the flow of blood
the forces generated by the heart and the resulting motion of blood through the cardiovascular system
Ohm’s Law Q (Blood flow) =
P(pressure difference from a to b)/R(resistance)
How is blood flow monitored externally?
Blood Pressure and heart rate
Blood moves from ______ pressure to _____ pressure
high; low
Blood is oppsed by:
resistance
Resistance is determined by:
Vessel length, radius, viscosity
What can affect the radius of a blood vessels?
diseases such as arterio atherosclerosis, stress: catecholamines constrict blood vessels and increase BP
99% of blood is made of:
RBC’s
The hematocrit is composed of:
RBC’s and plasma
T or F: An increase in RBC’s will cause an increased viscosity thus an increased resistance
TRUE
What will a decrease in RBC’s cause?
a decrease in blood viscosity
An increase in plasma/water will have what effect on viscosity?
a decreased viscosity
TPR=
total resistance pressure throughout vascular system
SVR=
resistance peripheral to heart and lungs
T or F: TPR has a direct effect on BP
False. SVR will have the most direct effect on BP
A decreased SVR will do what to BP?
cause a decreased BP
An increased SVR will cause:
and increased BP
An increased cardiac output (increased work for the heart to eject blood) is a result of an (increase/decrease) in SVR
increase
Shock can cause an (increase/decrease) in SVR
decrease
A measure of distance traveled in a given amount of time (speed) refers to:
velocity
Define laminar flow:
nonturbulent streamline flow in parallel layers(laminae).
In terms of blood flow “laminar flow” refers to
blood moving through the core centers of smooth vessels
Define turbulent flow:
flow in which the velocity at any point varies erratically.
What does “turbulent flow” mean when talking about blood flow?
created by cross flow caused by angles, rough areas, or obstructions in vessels
When assessing a patient for turbulent flow we listen for _________ and feel for__________.
bruits, thrills
What might a bruit in the abdomen signify?
a clot or aneurysm in the abdominal aorta
Where will the blood flow fastest in the vessel?
directly through the center
Where will blood flow slowest in a vessel?
Around the sides of a vessel
Define microcirculation:
Circulation of the blood in the smallest blood vessels.
T or F: Hemodynamics (pressure) is necessary in order to get blood through capillaries.
FALSE. Blood moves through capillaries according to concentration and osmosis/diffusion, but can effect hemodynamics.
What can cause a change in the microcirculation balance?
abnormal blood volume, abnormal resistance (turbulent flow), abnormal plasma, a leak in the vessel
What would happen in the absence of plasma proteins?
Plasma proteins regulate diffusion through capillaries by attracting fluid to them (high concentration of solutes). Without them blood flow through capillaries cannot be maintained. This will cause edema because fluid will still be moving to higher solute concentrations, but this will be into the interstitial space instead of through the vessel
Besides plasma proteins, what three other factors control microcirculation?
neuronal (SNS increases resistance and PNS decreases resistance), autoregulation, and hormonal
What role does ADH play in microcirculation?
controls the amount of water in the blood
What role does aldosterone play in microcirculation?
controls the amount of sodium in the blood
What role does atrial naturietic play in microcirculation?
gets rid of sodium by blocking sodium reapsorption
1.Which of the following will not cause an increase in vascular resistance: A. decreased viscosity, B. increased hematocrit, C. decreased number of blood vessels, D. decreased shear rate
A. decreased viscosity
Which of the following procedures would cause an increase in blood flow through a cylindrical tube? (Choose all that apply) a. increase tube diameter by 10%, b. decrease the tube length by 20%, c. decrease the blood viscosity by 30%, d. increase the driving pressure by 40%
ALL of the above.