Module 2.3 - Biofluid Transport III (Wave propagation) Flashcards
Recap: pressure pulse (or pressure difference) _______ as blood travels from heart down to aorta and arteries
increases (pressure itself decreases)
Where do reflections of pressure pulse occur in vessels?
At every point where properties or dimensions of the artery changes (site of partial reflection)
Governs how much of the pressure pulse will be transmitted vs. reflected
Ratio of vessels’ impedances (Z)
Z = rho*c/A
c = speed of pressure pulse
rho = density of blood
A = undisturbed area of vessel
Admittance
Inverse of impedance, a = 1/Z
Transmission coefficient
Describes the amplitude, intensity, or total power of a transmitted wave relative to an incident wave
Reflectance coefficient (Gamma)
Parameter that describes how much of a wave is reflected by an impedance discontinuity in the transmission medium
Recap: smooth muscle layer is _____ in artery and _____ in vein
Thick
Thin
Anastomosis
A surgical connection between two structures. It usually means a connection that is created between tubular structures, such as blood vessels or loops of intestine.
End-to-end anastomosis
Connecting sections of the same structure (ie. inserting a graft in the middle of a broken artery)
Bifurcation
The division of something into two branches or parts. In this case, a vessel with 2 branches
In an aortic-iliac vascular graft, how many potential sites would there be an expected reflection of the pressure pulse?
- Between aorta and parent graft
- At junction of parent graft
- Between iliac arteries and daughter grafts
T/F: If a vessel is replaced, the characteristics of the pressure pulse must be maintained to ensure proper blood flow
T
Conditions for proper blood flow with replaced vessel
T = 1
Gamma = 0
Condition for proper blood flow in a bifurcation or replaced vessel
Sum of admittances of all daughter vessels equals admittance of parent vessel
Why does T = 1 make sense for proper blood flow?
T = 1 implies entire wave is transmitted, no reflection
