Important
Concepts
Associated with
the Measurement
of Blood Pressure
BP is one of the
principal vital signs
Classification of hypertension
(elevated blood pressure) in adults
BP Classification
Systolic/Diastolic Values
Normal
119/79 or less
Prehypertension
120/80 to 139/89
Stage 1 Hypertension
140/90 to 159/99
Stage 2 Hypertension
160/100 or higher
Left heart
QRS
Electrocardiogram
P
Atrial
SYSTOLE
Pressure (mm Hg)
P
2nd
“Lup” = closing of L AV valve or Mitral valve
(1st heart sound)
Dicrotic notch
“Dup” = closing of Aortic valve
(2nd heart sound)
Aorta
Left ventricle
Atrial systole
Ventricular
volume (ml)
Review
of aortic
pressure:
T
1st
Heart sounds
Left atrium
EDV = End Diastolic Volume
ESV = End Systolic Volume
EDV
SV
SV = Stroke Volume
ESV
Atrioventricular valves
Aortic and pulmonary valves
Open
Closed
Open
Closed
Open
Closed
Ventricular
SYSTOLE
Ventricular
DIASTOLE
Blood Pressure (BP) when measured with a sphygmomanometer
mostly closely approximates aortic pressure.
Superficial temporal
artery
Facial artery
Common carotid
artery
Brachial artery
Radial artery
Femoral artery
Popliteal artery
Posterior tibial
artery
Dorsalis pedis
artery
More practically,
blood pressure (BP)
is a measure of
pressure in the
brachial artery (a
vessel located
a small distance
from the aorta). The
dots here represent
pressure points
located throughout
the body.
Blood Pressure (BP)
Force exerted by circulating
blood on the walls of the
brachial artery
(if measured traditionally)
Force exerted against
walls of a blood vessel
when the heart contracts
(systole)
Systolic Blood Pressure
Force exerted against
walls of a blood vessel
when the heart relaxes
(diastole)
Diastolic Blood Pressure
Average blood pressure
or mean arterial pressure
(MAP) is determined by
obtaining both systolic
and diastolic values of the
blood vessel.
(point of this exercise)
Where does your
blood pressure fall?
And YOU think
you have stress!
Left heart
QRS
Electrocardiogram
P
Pressure (mm Hg)
Atrioventricular valves
Aortic and pulmonary valves
P
2nd
“Lup” = closing of L AV valve or Mitral valve
(1st heart sound)
Dicrotic notch
“Dup” = closing of Aortic valve
(2nd heart sound)
Aorta
Left ventricle
Atrial systole
Ventricular
volume (ml)
Other concepts
to review:
T
1st
Heart sounds
Left atrium
EDV = End Diastolic Volume
ESV = End Systolic Volume
EDV
SV
SV = Stroke Volume
ESV
Open
Closed
Open
Closed
Open
Closed
Ventricular
SYSTOLE
Ventricular
DIASTOLE
Cardiac Output can be calculated with a quick and easy
mathematical formula (using the above information).
Volume of blood
pumped out by a ventricle
with each heart beat
Stroke Volume (SV)
Number of beats per
minute
Heart Rate (HR)
Graph showing the
change in volume (mL) of blood in
one “chamber” during a heart beat
EDV
diastole
systole
diastole
What is the volume of blood at the end of diastole?
Graph showing the
change in volume (mL) of blood
during one heart beat
ESV
diastole
systole
diastole
What is the volume of blood at the end of systole?
Graph showing the
change in volume (mL) of blood
during one heart beat
SV
diastole
systole
diastole
Therefore, what is the stroke volume?
Volume of blood (mL)
pumped by each ventricle
in one minute (min)
Cardiac Output (CO)
Cardiac Output (CO)
is
Heart Rate (HR) x
Stroke Volume (SV)
Example:
What would be the cardiac output of an individual
at rest (60 beats/min) and with no obvious heart
condition (use the stroke volume already given)?
Answer:
CO (mL/min) = HR (60 beats/min)  SV (70 mL/beat)
= 4,200 mL/min or 4.20 L/min
This means that over the course of one hour, one heart
chamber at rest could eject over 240 liters of blood.
That’s over 63 gallons!
Sixty-three gallons for a little over six and a half days …
this could fill a 10,000 gallon (small size) swimming
pool.
With continuous exercise (120 beats per minute), that
time could be cut in half (about 3 days)!
*1 Liter = 0.264172051 US Gallons
Measuring
Blood Pressure (BP)
Click below if you have a username &
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Interactive Physiology Exercise
(In order to make this work, an access code
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Steps: Click on Tutorials > Interactive Physiology >
Chapter 19 > Cardiovascular System >
Measuring Blood Pressure
(The plan here will be to complete all steps and the
quizzes/worksheets in lab class.)