Blood Pressure Flashcards
What is the Mean Arterial Blood Pressure (MABP)?
The driving force for blood flow through the organs/systemic circulation (everything except the lungs)
Why is Mean Arterial Blood Pressure important?
Ensures adequate blood flow to organ systems
What value is arterial blood pressure maintain at?
120/80 mmHg
What is systolic blood pressure (SBP)?
Pressure in arteries (aorta) during myocardial contraction (systole)
What is diastolic blood pressure (DBP)?
Pressure in arteries (aorta) during myocardial relaxation (diastole) i.e. when ventricles are refilling
How do you calculate pulse pressure?
SBP - DBP
How do you calculate Mean Arterial Blood Pressure?
DBP + 1/3 pulse pressure
OR
CO x TPR
What does TPR stand for?
Total peripheral resistance
Refers to systemic vascular resistance
When is blood pressure the highest?
Waking up
When is blood pressure the lowest?
Sleeping
What can you use to measure blood pressure?
A sphygmomanometer
Occlude the artery of an extremity (e.g. arm) with an inflatable cuff and by auscultation of for detection of Korotkoff sounds
What are the 2 main mechanisms of blood pressure regulation?
- Rapid regulation e.g. nerves, hormones
2. Long-term regulation e.g. blood volume
What are baroreceptors?
Mechanoreceptors that detect changes in blood pressure by detecting the degree of stretch in the blood vessel walls
Which 2 locations are baroreceptors most abundant?
- Aortic arch
2. Carotid sinus
Describe the carotid sinus
- Two carotid arteries supply the head and neck (right and left)
- Each carotid artery divides into 2 smaller arteries
- Where the artery wall is thinner and contains a large number of branching nerve endings - this are is the carotid sinus
Which nerve innervates the carotid sinus baroreceptors?
Nerve of Hering (a branch of the glossopharyngeal nerve; CN IX)
Which nerve innervates he aortic arch baroreceptors?
Aortic nerve (combines with vagus nerve)
Which baroreceptors (carotid sinus or aortic arch) are most sensitive to pressure change/changes in stretch?
Aortic arch baroreceptors
Have a higher threshold pressure
What is ‘normal’ BP?
120/80 mmHg