12. Pressure and Flow in Arteries and Veins Flashcards
What sounds are measured during the measurement of arterial pressure?
auscultation of Korotkoff sounds
What 2 pieces of equipment are used to measure arterial pressure for auscultation of Korotkoff sounds?
- sphygmomanometer (around arm)
2. stethoscope
Which artery is the stethoscope placed over to hear Korotkoff sounds?
over brachial artery (in the antecubital fossa) just below the cuff
What are the 5 stages of Korotkoff sounds?
(silence)
- tapping
- soft swishing
- thumping (crisp)
- muffled (blowing)
- silence
What do the first tapping sound heard indicate?
systolic pressure
What does it indicate if tapping sounds cease?
diastolic pressure (last audible sound)
What phase is systolic pressure usually heard at?
phase 1
What phase is diastolic pressure usually heard at?
phase 4/5
What blood vessels act as pressure reservoirs? What do they do?
elastic arteries; they damp down pressure variations
What is a pressure wave affected by? (4)
- stroke volume
- velocity of ejection
- elasticity of arteries
- total peripheral resistance (TPR)
What is a “normal” arterial pressure?
120/80 mmHg
What does arterial pressure (esp. pulse pressure) increase with naturally?
increases with age
Define MAP.
- mean arterial pressure in arteries over one cardiac cycle
Define pulse pressure.
- systolic pressure-diastolic pressure
- determined by stroke volume and arterial compliance
What happens to pressure as blood travels through a vascular tree?
pressure decreases gradually
What is the pressure drop like in arteries?
- small drop in arteries (from ~95 to 90mmHg)
What is the resistance conduit like in arteries?
low resistance conduit
What is the pressure drop like in arterioles?
- large drop in arterioles (from ~90 to 40mmHg)
What is another name for arterioles?
resistance vessels (high resistance)
What is the pressure like when blood gets to capillaries?
Already low (it’s low in arterioles so lower in capillaries) which is good because they are thin-walled
What is the pressure difference/drop in veins?
- small pressure difference/drop (from ~20 to 5mmg)
Where is systemic filling pressure found?
pressure in venules and veins draining into r.atrium