Pressure & Flow in Arteries and Veins Flashcards
What is systolic pressure?
The pressure of the blood during the heart contraction (systole).
When left ventricle contracts and pushes blood into the aorta.
What is diastolic pressure?
The pressure of the blood when the heart is at rest between heart beats (diastole).
What is the difference between systolic and diastolic blood pressure?
The pulse pressure
How can blood pressure be calculated
Flow x Resistance
What factors increase systolic pressure
Increased cardiac output
Reduced blood vessel compliance
Increased pulse pressure - increases w atherosclerosis
What are korotkoff sounds?
Sounds that medical personnel listen for when they are taking blood pressure using a non-invasive procedure
What is the effect of high diastolic pressure on the aorta?
There is a higher total peripheral resistance so the aorta finds it harder to release blood
What is the effect of elastic vessels on pressure variations?
Dampens them down
What happens to the aorta during ventricular contraction?
- Ventricle contracts
- Semilunar valves open. Blood pours from ventricles flow into the arteries.
- Aorta and arteries expand and store pressure in elastic arteries
STRETCH
What happens to the aorta during ventricular relaxation?
- Ventricular relaxation
- Semilunar valve shuts, preventing flow back into ventricle
- Elastic recoil of arteries sends blood forward into rest of circulatory system
RECOIL
What is pressure wave effected by?
Stroke volume
Velocity of ejection
Elasticity of arteries
Total peripheral resistance
What is the dicrotic notch?
Low point after closure of the aortic valves and precedes the secondary dicrotic wave.
The notch is frequently used as a marker for the end of the ventricular ejection period.
What feature of arteries allows maintainance of high pressure during high systolic pressure?
Elastic fibres
How does pressure change from arteries - arterioles - capillaries - venules?
Aka through the vascular tree
Decreases
Drops in vascular tree with numbers
Small drop through arteries (95 to 90mmHg)
Large drop through arterioles (90 to 40mmHg)
Pressure is low when reach capillaries which is good bc they are thin walled
Leaves a small pressure difference pushing blood back through veins (from 20 to 5mmHg)
What is name given to the blood pressure left to bring the blood back to the heart?
Systemic filling pressure