Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
32 Cards in this Set
- Front
- Back
|
Vasodilation or vasoconstriction occurs mostly (and with great effect) in which blood vessels?
|
arterioles
|
|
|
Where is most blood found in the body?
|
systemic circulation (specifically veins since they store blood)
|
|
|
How is velocity of blood flow related to the cross sectional area of a vessel?
|
Inversely proportional. V= (F/A). Greater cross sectional area (vasodilation) = slower flow
|
|
|
What is the ideal systolic/diastolic pressure of the pulmonary artery?
|
25/8 (averages to 16)
|
|
|
What is the ideal systolic/diastolic pressure of the aorta?
|
120/80
|
|
|
Why is it important that capillary pressure doesn't rise above 17 mmHg?
|
capillaries have pores. if the pressure rises too much, the hydrostatic force will cause leaking of fluid or particles out of the vessel (edema, exudate etc.)
|
|
|
How do local tissues regulate blood flow with regard to tissue need?
|
vasodilation and constriction
|
|
|
How is blood flow related to resistance?
|
inversely proportional; more resistance = less flow
|
|
|
How is blood flow related to pressure difference?
|
proportional; more pressure difference = more flow
|
|
|
If the pressure at both ends of a blood vessel is 100 mmHg, what will the blood flow be in that vessel?
|
no blood flow. there needs to be a pressure difference between the ends of the vessel for flow to occur
|
|
|
Normal cardiac output is ....
|
5 L/min
|
|
|
2 mechanisms for measuring blood flow
|
Electromagnetic Flowmeter or Ultrasound/Doppler Effect
|
|
|
What is laminar flow of blood?
|
the blood is unidirectional and faster in the center of the vessel due to less interaction/resistance form the vessel wall.
|
|
|
What is turbulent flow of blood?
|
blood is not laminar; more erratic and disorderly
|
|
|
What is a parabolic velocity profile?
|
shows laminar flow; flow is faster in the center of the vessel due to less interaction/resistance form the vessel wall.
|
|
|
What is the Reynold's number?
|
tells the likelihood of turbulence flow. R = ((velocity)(diameter)(density))/viscosity
|
|
|
When pressure in an artery is 100 mmHg, what do those numbers and units mean?
|
in that artery, there is enough pressure on the vessel wall to raise a column of mercury 100 mm high
|
|
|
When pressure in an artery is 10 cm H2O, what do those numbers and units mean?
|
in that artery, there is enough pressure on the vessel wall to raise a column of water 10 cm high
|
|
|
Which circuit has more resistance? Systemic or pulmonary?
|
Systemic has about 7x more resistance
|
|
|
How is conductance related to resistance?
|
inversely proportional. more resistance = less conductance
|
|
|
What is conductance?
|
how much flow occurs. inversely proportional to resistance
|
|
|
How is conductance related to vessel diameter?
|
conductance = diameter^4
|
|
|
What is Poiseuille's Law stating in relation to blood flow?
|
the closer flow is to the vessel wall, the slower it is due to resistance/interaction from the wall. this is how we get laminar flow
|
|
|
Total Peripheral Resistance (in series) =
|
R+R+R+R+R since they are in series (artery to capillary to vein)
|
|
|
1/ Total Tissue Resistance (in parallel)=
|
(1/R)+(1/R)+(1/R)+(1/R) since they are in parallel within tissues and organs
|
|
|
Total Conductance in parallel =
|
C+C+C+C+C in parallel (opposite of resistance since they are inversely proportional)
|
|
|
Amputation of a limb has what effect on total peripheral resistance and conductance?
|
since it is in parallel, resistance increases and conductance decreases
|
|
|
Excess hematocrit (e.g. polycythemia) has what effect on blood flow?
|
slower flow as blood is more viscous
|
|
|
Major changes in BP don't usually effect the tissues blood supply. Why?
|
tissues "auto-regulate". they are able to constrict/dilate to keep a constant supply of blood
|
|
|
If BP was high in a certain tissue, what effect would occur within the tissue arterioles to auto-regulate the amount of blood flow?
|
constriction. there is too much blood getting to the tissue, so it closes of vessels (increases resistance/constricts)
|
|
|
Inhibition of sympathetics has what effect on vessel diameter?
|
sympathetics constrict, so inhibition leads to dilation (lower BP, more flow)
|
|
|
Excess of sympathetics has what effect on vessel diameter?
|
sympathetics constrict = smaller diameter = higher BP = less flow
|
