Peripheral Circulation Flashcards
What two properties do the aorta and large arteries exhibit?
Elasticity (recoil)
Compliance (distensibility)
What blood passageway is the main site of peripheral resistance?
Arterioles
What are the two main functions of capillaries?
Gas/nutrient exchange and filtration
What are two main properties of veins?
High distensibility
High reserve blood volume
What is the role of compliance in arterial blood pressure?
Distension in systole limits the rise of blood pressure in the walls of the vessel (i.e. the Windkessel effect)
What is the role of recoil in arterial blood pressure?
Recoil in diastole slows the rate at which blood pressure drops and helps propel blood further in the system
In what two conditions does arterial compliance decrease? What does this decrease cause?
Aging and vascular disease (e.g. atherosclerosis)
Increased systolic pressure; increased pulse pressure
What are two methods for calculating mean arterial pressure?
Cardiac output x Total Peripheral Vascular Resistance
OR
Diastolic Pressure + 1/3 (Pulse Pressure)
What are two methods of measuring arterial pressure?
Indirectly: sphygmomanometer
Directly: arterial cannulation
What are the two main determinants of arterial pulse pressure?
1) Stroke volume (lower SV yields lower pulse pressure)
2) Arterial compliance (lower compliance increases systolic BP and decreases diastolic BP)
How might stroke volume changes manifest?
Increases: aortic regurgitation, increased volume
Decreases: hemorrhage, aortic stenosis, MI, CHF
What are three relevant factors in the transmission of pulse pressure?
1) Transmission of the pulse wave through the arteries is rapid (faster than blood flow itself)
2) If arteries are less compliant, the transmission is faster
3) A fast pulse wave is an indicator for cardiac outcomes
