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24 Cards in this Set
- Front
- Back
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What is the relationship between resistance and diameter?
If D is halved, how does this affect R? |
R∝1/(D^4)
R increases 16 times |
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What is the relationship between resistance and length?
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R∝L
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In terms of varying pressure, in which direction will a fluid flow?
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High pressure to low pressure
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What is the rate of movement of fluid?
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Q(dot) = Cardiac Output[L/min]
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If total blood volume is 5L and the time for one trip through circulation is 1 minute, what is the cardiac output?
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5L/min
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How does cardiac output relate to pressure and resistance?
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Q(dot) = ΔP/R
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What structure regulates cardiac output?
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Heart
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What structure regulates resistance to blood flow?
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Smooth muscle of vessels that change diameter of vessels
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What effect does blood doping have on cardiac output?
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Increased viscosity of blood (increased RBCs) means increased resistance, and increased ΔP, which means heart has to work harder
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Contrast systole with diastole.
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Systole: when heart contracts
Diastole: when heart relaxes |
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How does systolic pressure generally compare with diastolic pressure?
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Systolic pressure is usually greater
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Where is systolic pressure the greatest?
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Larger arteries
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Where is most resistance in the body?
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In arterioles; have most regulation of vessel diameter
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Where is there the greatest change in pressure in blood flow?
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Small arteries --> Arterioles
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How does pressure in the systemic circuit compare to pressure in the pulmonary circuit?
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Much lower pressure in pulmonary circut
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How does the cardiac output of systemic flow compare with cardiac output of pulmonary flow?
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They're the same. Cardiac output is constant.
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What vessels are considered stressed? Unstressed?
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Stressed = Arteries
Unstressed = Veins |
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Where is most blood found in circulation?
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In veins: ~65% of blood reservoir in veins
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How are arterioles able to shunt blood? What's the purpose of this?
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Smooth muscles in arterioles change diameters in wall and can shunt blood to specific places (like away from gut)
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What is the cardiac cycle?
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Pressure and volume changes involved in pumping of heart
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What effect would a stiffened ventricle (stiff heart) have on diastole?
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Incomplete filling of ventricle bc of increased resistance (this is a passive process)
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On an ECG, what occurs during P wave? QRS? T?
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P wave: Atrial depolarization
QRS complex: Ventricular DEpolarization, Atrial REpolarization T wave: Ventricular REpolarization |
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Where is the SA node located (generally)? Describe its innvervations.
Is innervation necessary? Why or why not? Describe the path from SA node. |
SA Node in mid-left RA
Innervated by Cardiac Plexus (sympathetic) and Vagus (parasympathetic) Can keep pace without neural input (it's a pacemaker) Signal spreads to AV node (and R/L atria--depolarization) DELAY (allows for filling) to bundle of His (common bundle) Splits to R bundle branch and L bundle branch Go to Purkinje fibers in R and L ventricles (Ventricular DEpolarization) |
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What occurs during heart block?
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SA not producing pace; AV node takes over
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