Pressure and flow in arteries and veins Flashcards
How do you measure arterial pressure?
Sphygmomanometer & stethoscope gradually reduce pressure silence tapping thumping muffled
as blood flows more freely
Tapping =systolic
Muffled=diastolic pressure
What is a pressure wave?
Graph showing pressure change from diastolic to systolic
What is normal arterial pressure?
120/80
What happens to arterioles if youre doing significant exercise?
dilate around sketeltal muscles
What happens to arterioles if youre doing significant exercise?
dilate around skeletal muscles
What is the drop in pressure from heart to arteries?
from 95-90mmHg
What is the drop in pressure from arteries to arterioles?
90-to 40mmHg
What fraction of pressure is the pulmonary pressure compared to systemic?
about a 1/5th
What does velocity of blood flow depend on?
Total cross sectional area
High cross sectional area=
low velocity
How is flow different from velocity
Flow=volume
ie blood may be slower VELOCITY in capillaries but there are so many of them that flow is unaffected?
How does gravity affect veins?
Causes venous distension in legs
Drops EDV to MAP
What can gravity cause in veins?
orthostatic (postural) hypotension
Can cause venous collapse in neck
What is the height of jugular collapse used to estimate?
CVP
What is the significance of the skeletal muscle pump? (4 pts)
- Rhythmic vs static exercise
- hot guardsmen-standing for long collapse
- deep vein thrombosis
- varicose veins-Under high pressure
