Physiology Flashcards
What is blood pressure?
Outwards (hydrostatic) pressure exerted by blood on the blood vessel walls
What BPs are measured in clinical practice?
Systolic
Diastolic
What is systolic BP?
Pressure exerted by blood on aorta and systemic artery walls when heart contracts
What is the normal range of systolic pressure?
<140 mm Hg
What is diastolic BP?
Pressure exerted by blood on aorta and systemic artery walls when heart relaxes
what is the normal range of diastolic BP?
<90 mm Hg
What is hypertension?
Clinic Blood pressure of 140/90 mm Hg or higher
Daytime average of 135/85 mm Hg or higher
What is pulse pressure?
difference between systolic and diastolic blood pressures ( normally between 30 and 50 mmHg)
What is mean arterial blood pressure?
Average arterial blood during a single cardiac cycle (contraction and relexation)
why is MAP not the average of systolic and diastolic?
Diastolic portion of cycle is twice as long as systolic
How is MAP calculated?
[(2 x diastolic) + systolic] / 3
OR
diastolic + (systolic-diastolic)/3
Whats the normal range for MAP?
70-105 mm Hg
What MAP is needed to perfuse brain heart and kidneys?
60 mm Hg
What reflex is designed to regulate blood pressure?
Baroreceptor reflex
Where are the baroreceptors located?
By carotid sinus and aortic arch
what nerve is associated with carotid baroreceptor?
Herring’s nerve
what nerve is associated with aortic baroreceptor?
Vagus nerve
What kind of receptor is a baroreceptor?
Mechanoreceptor- sensitive to stretch
What does a fall in MAP do to baroceceptor afferent neurones?
Decreases firing rate
What does a rise in MAP do to baroceceptor afferent neurones?
increases firing rate
