Blood pressure Flashcards
What is blood pressure?
force blood exerts against inner walls of blood vessels
Blood pressure refers to systematic arterial pressure
What is arterial blood pressure
Expansion and recoil of the wall of an artery as ventricles contract and relax- known as a pulse
What are the 4 common pulse points
radial artery
carotid artery
branchial artery
femoral artery
What does venous blood flow do?
BP decrease as distance from the heart increases
Blood flow through the venous system is only partially the result of heart action
What does heart action depend on?
Skeletal muscle
contraction
breathing movements
vasoconstriction of veins
What do contraction of skeletal muscles do?
squeeze blood back up veins one valve section at a time
What does respiratory movement do?
Create differences in thorastic and abdominal pressure- draw blood back up veins
What does vasoconstriction do?
Returns blood to the heart- initiated by sympathetic reflexes when venous BP is low
What do veins also act as?
A reservoir for blood- encase of blood loss and decreased BP, vasocontraction sends blood out of the reservoir
What is the factor that influences atrial blood pressure
cardiac output=stroke volume x heart rate
What is stroke volume?
Amount of blood discharged from each ventricle with each contraction (70ml)
What is heart rate?
Number of beats per minute (72)
What happens if stroke volume or heart rate increases?
Cardiac output also increases
What is blood volume?
Sum of the volume of the plasma and formed elements
What are the 5 factors that influence BP
Blood volume increase HR increase Stroke volume Increase Blood viscosity increase peripheral resistance increase
