Download Ventricular systole

Exercise 22: Human Cardiovascular
Physiology- Blood Pressure and Pulse
Determination
Cardiac Cycle
aortic pressure
ventricular pressure
atrial pressure
ventricular volume
EKG
LUB
DUB
heart sounds
Terms
 Systole = contraction of ventricles
 Diastole = relaxation of ventricles
 Cardiac cycle= events of one complete heartbeat,
during which both atria and ventricles contract and
then relax
AV valves open during
ventricular diastole
AV valves closed during
ventricular systole
AV valves open when ventricular pressure is less than atrial pressure.
AV valves close when the pressure inside the ventricle rises
Semilunar valves closed
during ventricular diatole
Semilunar valves open
during ventricular systole
Semilunar valves open when ventricular pressure exceeds that of the
large arteries leaving the heart.
Semilunar valves close when ventricles relax at the end of systole to
prevent backflow
Pressure in the heart
is highest during
ventricular systole.
Pressure in the heart
is lowest during
ventricular diastole.
1 cardiac cycle
Filling Heart Chambers: Cardiac
Cycle
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular
filling
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Isovolumetric
Ventricular
contraction phase ejection phase
Isovolumetric
relaxation
Ventricular systole
(atria in diastole)
Early diastole
LUB DUB is caused by the closing of the heart valves- the
first sound is longer and louder and the second sound, Figure 11.7
which is short and sharp
Abnormal Sounds might indicate…….
1. Valve deformities that can seriously hamper cardiac function
and ultimately weaken the heart.
2. Abnormalities in the conduction system of the heart.
3. Inadequate blood supply to the heart.
Cardiac ischemia is the name
for lack of blood flow and
oxygen to the heart muscle.
“Heart block" or "AV block." is
when the electrical impulse
signal from the heart's upper to
lower chambers is impaired or
doesn't transmit.
Heart valve problems: Stenosis is when heart valves don't open enough to allow
the blood to flow through as it should. Regurgitation is when the heart valves
don't close properly and allow blood to leak through. Mitral valve prolapse is
when the valve leaflets bulge or prolapse back into the upper chamber. They may
not close properly and blood may leak back through.
Pulse
 Pulse
 Alternating surges of pressure (expansion then recoil) in
an artery that occur with each beat of the left ventricle.
 Monitored at “pressure points” in arteries where pulse
is easily palpated
 Pulse averages 70–76 beats per minute at rest
Pulse
Figure 11.18
Has an artery or vein been cut?
How to tell.
 Blood from a vein would be darker than from an artery.
If you punctured an artery or vein then the blood flow
would continue until you put pressure on it to allow for
the blood to clot.
 An arterial cut will spurt blood. Vein will just flow out.
Blood Pressure
 The pressure the blood exerts against the inner blood
vessel wall.
 Systolic pressure—pressure in the arteries at the peak of
ventricular contraction
 Diastolic pressure—pressure in the arteries when
ventricles relax
Comparison of Blood Pressures
in Different Vessels
Figure 11.19
Measuring Arterial Blood Pressure
with Sphygomomanometer
Figure 11.20a
Auscultation is the technical term for listening to the internal sounds of the body, usually
using a stethoscope
Sounds of Korotkoff
Sounds caused by the resumption of blood flow into the forearm.
Auscultatory blood pressure measurement showing
onset of Korotkoff sounds at systolic pressure, and
diminishing sounds as diastolic pressure is reached.
Figure 11.20b
http://www.thinklabsmedical.com/stethoscope_community/Sound_Library
Blood Pressure
 Write systolic pressure first and diastolic last
 (120/80 mm Hg)
 Pressure in blood vessels decreases as distance from the
heart increases…..veins are further away from the heart
than arteries are.
Blood Pressure: Effects of
Factors
 BP is blood pressure
 BP is affected by age, weight, time of day, exercise, body
position, emotional state
 CO is the amount of blood pumped out of the left
ventricle per minute
 PR is peripheral resistance, or the amount of friction
blood encounters as it flows through vessels
 Narrowing of blood vessels and increased blood volume
increases PR
 BP = CO  PR
Blood Pressure: Effects of
Factors
 Neural factors
 Autonomic nervous system adjustments (sympathetic
division)
 Renal factors
 Regulation by altering blood volume
 Renin—hormonal control
Blood Pressure: Effects of
Factors
 Temperature
 Heat has a vasodilating effect
 Cold has a vasoconstricting effect
 Chemicals
 Various substances can cause increases or decreases
 Diet
Factors Determining Blood
Pressure
Figure 11.21
Variations in Blood Pressure
 Normal human range is variable
 Normal


140–110 mm Hg systolic
80–75 mm Hg diastolic
 Hypotension
 Low systolic (below 110 mm HG)
 Often associated with illness
 Hypertension
 High systolic (above 140 mm HG)
 Can be dangerous if it is chronic