Class 9 Flashcards
Blood pressure represents the force exerted by blood against the __________________ during the _________________. It is a combination of ________________ pressure & __________________ pressure
• arterial walls
• cardiac cycle
• hydrostatic
• hemodynamic
What is hydrostatic pressure?
The pressure applied equally by water on the walls of its container
What is hemodynamic pressure?
Is exerted as a result of the flow of blood & changes according to the contours & branching of the walls.
Although, there is some amount of pressure in all parts of cardiovascular system except entry into the RA, arterial blood pressure is central to delivery of ________________ into body’s tissues. Its highest in the ________________________ & becomes increasingly less intense as vessels ______________ in size.
• perfusion
• aorta/large aa.
• decrease
The elastic stretch & recoil properties of large arteries give rise to ______________________, but this becomes completely attenuated into one ___________________________ as blood arrives at capillary bed level & moves through the veins.
• two pressure poles
• milder propellant flow
The “bellows” effect of large aa. is necessary to mitigate force & move ______________ through the __________________, but it must be removed by the time blood is delivering _______________ in a steady stream to the body’s cells.
• blood
• vascular circuit
• nutrients
The two pressure poles reflect the impact of _____________________________________.
the two phases of the cardiac cycle on the aorta and its immediate branches.
What is systolic pressure?
Highest reading achieved as an ejection of blood
What is stroke volume?
Moves into the vessel
What is diastolic pressure?
Lowest reading after the blood has left the vessel.
What is pulse pressure?
Difference between systolic & diastolic pressures is called pulse pressure. It represents force of LV contraction as it “pushes” blood into the aorta—in other words, how hard heart is working. Pulse pressure tends to increase when heart is working harder
What is mean arterial pressure?
Average pressure in large arteries. MAP = diastolic pressure + ⅓ of pulse pressure. Reading represents quality of perfusion. If average blood pressure is either too high or too low, blood flow through capillaries will not be optimal for nutrient delivery to cells. MAP is carefully monitored in intensive care patients.
By convention, blood pressure is taken at brachial artery, where normal BP is 120/80 (some argue normal is closer to 110/70 in women). Using 120/80 as reference point, systolic pressure is 120, diastolic is 80, pulse pressure is 40, & MAP is 93.3.
Determinants of Blood Pressure - what is Blood Volume?
The higher the volume of blood in the system, esp. in core circulation, the harder the heart & vessels have to work to pump it.
Determinants of Blood Pressure - what is Vessel Compliance?
» elastic characteristics of large vessels reduce/dampen systolic pressure as LV stroke volume enters them, & their elastic recoil helps maintain baseline pressure during diastole
» capacitance function of veins diverts blood volume from arterial tree to help manage pressure
» state of constriction or dilation of small arteries & arterioles influences how readily blood leaves core circulation to flow into tissue beds; easy flow reduces blood pressure, significant peripheral vasoconstriction increases blood pressure
Determinants of Blood Pressure - what is Cardiac Output (CO)?
Quantity of blood heart pumps into systemic circulation each minute; its a factor of heart rate & stroke volume; increased heart rate & larger SV both increase cardiac output; increase in CO can cause arterial pressure to rise.