Flashcards in Blood Pressure Deck (41)
What is Blood Pressure?
The force the blood exerts on the walls of blood vessels.
What does blood pressure reflect?
Reflects how hard the heart is working to pump blood (Normal is 120/80)
How is the pressure described?
As a fraction: Systole and Diastole
What is systole?
The top number, cardiac work phase
What is systolic pressure?
The force that the blood exerts in the arteries when it is ejected from the left ventricle.
What is Diastolic pressure
The force the blood exerts in the arteries when the ventricles are relaxed.
How is blood pressure commonly measured?
With a sphygmomanometer and the brachial artery.
What is pulse pressure?
- The difference between systolic and diastolic pressures.
- Represents the force that the heart generates each time it contracts.
- Normally 40
- Represents contractile force
What affects blood pressure?
- Cardiac output
-peripheral (systemic) vascular resistance
(BP = CO × PVR, where BP is blood pressure, CO is cardiac output, and PVR is peripheral vascular resistance).
What is cardiac output?
The amount of blood the heart pumps in 1 minute.
(CO = SV x HR)
Other variables that influence blood pressure?
-blood volume and viscosity
- heart rate
(Typically, increases in these variables will increase blood pressure)
Which variable is an exception, for which decreases increase blood pressure?
What is stroke volume?
amount of blood ejected from the heart with each contraction.
What is Ejection Fraction?
How much blood the left ventricle pumps out per contraction (normal range is 50-70).
What is Peripheral vascular resistance (PVR)?
the force opposing the blood in peripheral circulation
What happens to the Peripheral vascular resistance as the diameter decreases?
The PVR increases
(Increases as blood vessel diameter decreases)
What does the Ejection Fraction range measure?
It can help diagnose and track conditions that impact cardiac output.
What does the Stimulation of the SNS do when it initiates systemic vasoconstriction?
Raise blood pressure
What helps aid in hypotension?
(vasoconstriction is helpful in mitigating hypotension, such as occurs with shock)
What happens with Shock? Is there vasodilation or vasoconstriction?
Vasodilation (causing hypotension)
What is Afterload?
- The pressure needed to eject blood (factor of blood viscosity and PVR).
- The pressure that the left ventricle must exert to get the blood out of the heart and into the aorta.
What does Peripheral resistance affect?
The higher the Afterload?
The harder it is for the heart to eject blood, thus lowering stroke volume.
Amount of blood returning (factor of blood volume and venous return)
Afterload, stroke volume is affected by?
The amount of blood returning to the heart that the heart must then manage.
What two things can affect blood pressure?
Afterload and Preload
What happens as both Afterload and Preload increase?
Blood Pressure increase
What hormones impact blood pressure?
- Antidiuretic Hormone (ADH)