HTHSCI 1H06 B Lecture 5: Hemodynamics and Blood Notes
22 Jun 2018
School
Department
Course
Professor
HEMODYNAMICS & BLOOD
D
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¢§ E. 33 D
Blood Flow
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Idef .)the volume of blood that flows through any tissue in agiven period of time IMYMM )
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total blood flow =CO and CO =HRXSV
Distribution of Cardiac Output
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Heart Rate
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stroke volume
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Pressure Difference 1high →low )T
•←Pressure →
Resistance to blood How
1t
Blood Pressure
•ldett Force exerted by the blood on the walls of a vessel
"
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generated by ventricular contraction
•
Pressure falls steadily in systemic circulation with
distance from left ventricle
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35mm Hg entering the capillaries
-~0mm Hg entering the right atrium
•
It decrease In blood volume 710%
,
BP drops
•
Water retention 4 =BPT
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Them ,
cross sectional Blood should slow down as H
Area moves through capillary
network for gas and
nutrient exchange
Blood Pressures
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systolic pressure :highest )occurs during ventricular contraction systolic Pressure
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Diastolic pressure ! occurs during ventricular relaxation
... ..}Pulse Pressure
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Pulse pressure :difference in systolic and diastolic pressures which gives an
Diastolic Pressure
Indication of overall cardiovascular health
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Mean pressure ! average pressure across the system 183 mmHg)Mofaesnsure
Use Pressure
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systolic -Diastolic
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Example I:BP is normal 1120 mmHg 180 mmHg)
Pulse Pressure IPP)is 120-80=40 mmHg pouting indicates
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Example 2:Bp =140160 ,then pp = go mmHg
Something is wrong
Mean Arterial Blood Pressure
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Mean ABP =Diastolic + 431 Pulse Pressure )
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Mean ABP =COX TPR
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significance :system is designed to maintain Mean ABP
Pulse Points
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If a vessel is close to the surface and near abony structure apulse can be found
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Pulse is agood indicator of heart rate ,strength ,
and perfusion
Factors Affecting Blood Pressure
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cardiac Output Pressure =Flow × resistance
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Blood Volume →Iv blood volume =tblood pressure
↳Flow =Pressure Iresistance
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Peripheral vascular Resistance
Vascular Resistance
•(deft friction between blood and the Vessel walls
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Blood Vessel radius
>
Big vessel = more room for blood to move freely =Iv vascular resistance
>Small vessel =harder For blood to How through =4vascular resistance
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Blood Viscosity thickness )
>
the thicker the blood (twater v),the Tvascular resistance
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Blood vessel length
>the longer the blood vessels ,
the Tvascular resistance
>blood vessels are longer in those who are overweight
•Arterioles (resistance vessels )control BP by changing diameter
can undergo ✓aso dilation or vasoconstriction
