Human Phys 4.1 Flashcards
What are all blood vessels?
Distensible (elastic)
What does the elastic nature of arteries allow them to do?
Buffer fluctuations in pressure and pulsatile output to deliver constant non-pulsatile blood flow preventing transmission of excess energy to target organs
What will repeated exposure to pulsatile pressure/flow to high flow organs cause?
Micro vascular hypoperfusion and ischemia
How much more distensible are veins than arteries?
8x more
Why do veins serve as blood reservoirs?
They are much more distensible than arteries (hold 64% of blood volume)
Vascular compliance
Volume/pressure
Compliance
Total quantity of blood that can be stored in a given portion of the circulation
What are more compliant between veins and arteries?
Veins
Elastance
Pressure/volume
What has higher elastance between veins and arteries?
Arteries
Why are IVs given in the veins only?
Because a change in volume does not effect pressure as much
Arteries (pressure and volume)
Pressure increases high and volume stays low
Veins (pressure and volume)
Volume increases high pressure stays low
Stress relaxation
Property or biological tissues that is related to their viscoelastic properties
What happens to blood vessels when exposed to increased pressure?
They show delayed stretching allowing pressure to normalize
What is a way that vasculature responds to hemorrhage?
Delayed compliance (reverse stress relaxation)
What would happen if arterial distensibility was absent (arterial stiffness)?
Blood would only flow during systole and no flow would occur during diastole
What are factors affecting pulse pressure?
Increase in SV increases pulse pressure
Increase in Arterial compliance decreases pulse pressure
What happens during stiff arteries?
Velocity is higher because there is no wasted energy to expand vessels (but causes no flow during diastole) (poor ventricular filling)
What happens between SBP and DBP as we age?
It gets farther apart due to artery stiffness
What does increase stiffness result in?
Increased pulse wave velocity (pulse wave velocity is bad)
What is the most beneficial exercise for arterial stiffness?
Aerobic exercise
Arteriosclerosis
Stiff arteries (low compliance)
Aortic stenosis
Diminished blood flow due to narrow openings
Patent ductus arteriosus
More than 1/2 of blood pumped into aorta flows backward into the PA causing a significant drop in DBP
Aortic regurgitation
Aortic valve does not close and blood flows back into the LV causing pressure to drop close to zero
What is damping caused by?
Resistance of blood movement
Compliance of vessels
Where does most damping occur?
Arterioles (because most resistance and least compliance is found here)
What is the first sound?
Systolic BP
What is the disappearance of the sound?
Diastolic BP
What is the BP equation?
BP=CO x TPR
What are the two physical determinants of pulse pressure?
Arterial compliance and the change in arterial volume
What are the two physiological determinants of mean arterial pressure?
Cardiac output and total peripheral resistance
