Blood Vessels: Fig 13.8 and Fig 13.9
Regulating Blood Flow to Tissues: Fig 13.10
ENDOTHELIAL CELL FACTORS:
EDRF ( nitric oxide or NO)
ENDOTHELIN ( peptide vasoconstrictor)
ADENSOINE AND RELATED ADENINE NUCLEOTIDES
(vasodilators)
Autoregulation
Myogenic mechanism
Tissue metabolism
H+ (lactic acid &
co2)
Adenosine & adenine nucleotides
Krebs cycle intermediates
Compliance: Fig 13.13
Capillary Exchange: Fig 13.12
Distribution of Blood: Fig 13.14
Blood Flow
How does the body determine distribution
of blood flow (ml/min)?
F = 
P
/ R
or
R = P
/ F
P1 = 100 mm Hg
P2 = 10 mm Hg
FLOW = 10 ml / min
POISEUILLES LAW
F = P
r4
8 
L
Parallel Blood Flow: Fig 13.15
Total peripheral resistance (TPR)
Flow in ml/min = k x p
TPR = 1/k
R = P
/ F
= 90 mm Hg / 10 ml/min
= 9 mm Hg / min/ml
= 9 PRU
Area and Velocity
A1 V1 = A2
V2
Since you cannot measure flow (or CO), what
can and does your body measure and monitor to assess the delivery of blood?
PRESSURE
PRESSURE MEASURED BY BARORECEPTORS
Why not measure blood flow (i.e.,
Cardiac Output)?
BLOOD PRESSURE IN mm Hg
BP = CO x TPR
Blood Pressure
Systolic
Diastolic
Average or Mean BP
Primary Factors Affecting BP
DP --> HR and TPR
SP --> SV (VR & EDV), TPR, (and DP)
PP --> SV and EDV (VR & HR)
Increased HR
Increased SV
Increased TPR
Primary Factors Affecting BP
DP --> HR and TPR
SP --> SV (VR & EDV), TPR, (and DP)
PP --> SV and EDV (VR & HR)
HR --> Diastolic BP and mean BP
SV --> PP and SP
TPR ---> mean BP
SV and TPR --> VR
Predictions: ACh
Decreased HR --> Decreased DP
Decreased TPR --> Decreased average BP
Increased filling time --> Increased SV
(if VR does not decrease too much)
Decreased TPR --> Decreased VR
Decreased CO
Predictions: Propranolol
Decreased contractility --> decreased SV
& PP
Decreased HR --> decreased DP
Minimally Increased TPR --> no real increased
average BP (?)
But, decreased HR and more efficient beat
at a lower BP!
Predictions: NE/EPI
Increase HR
Increase TPR/Decrease TPR
Increase SV
Increase VR
Increase CO
Increase DP (but Epi much less so!), SP,
PP, & average BP