1. Local Control of Blood
Flow
By:
M. Rasjad Indra
Lab. Ilmu Faal FK UNIBRAW

2. Introduction
 The greater the metabolism  the greater
its blood flow
– Liver: 95 ml/min/100 g of liver tissue.
– Kidneys: 1100 ml/min  cleansing the blood.
 The importance of blood flow control 
effective & efficient
– Serving metabolic need
– Efficient heart workload.

3. Mechanism of Blood Flow Control
 Acute control (rapid changes in local vasodilatation /
vasoconstriction):
– Effect of tissue metabolism
– The availability of oxygen changes.
– Two basic theories:
 Vasodilator theory: adenosine; CO2; histamine; K+ & H+
 Oxygen lack theory: vasomotion in metarterioles & precapillary
sphincters.
– Other nutrients besides Oxygen:
– Lack of glucose  vasodilatation
– Vitamin B deficiency  vasodilatation

5. The examples of acute metabolic
control of local blood flow
1. Reactive hyperemia
• Blocked (seconds – hours)  unblocked
• Blood flow increases to 4 – 7 times normal
• Depends on how long it is blocked.
2. Active hyperemia
• Tissue activity lack of nutrient & release
vasodilator substances.
• Local blood flow increases 20 times in
muscle during heavy exercise.

6. Blood flow control & The arterial
pressure changes
 Acute autoregulation theory:
1. The metabolic theory
2. The myogenic theory (still doubtful !!)
 Endothelial-Derived Relaxing Factor
“EDRF” (NO):
– Rapid flow of blood  shear stress NO
release  relaxes the local arterial wall.

8. Long Term Blood Flow Regulation
1. Change in Tissue Vascularity
– Reconstruction to meet the needs of the
tissues
– Role of Oxygen in Long-Term Regulation.
– Vascular Endothelial Growth Factors:
1. VEGF
2. FGF
3. Angiogenin
2. Collateral Circulation:

9. Humoral Regulation of The Circulation
1. Vasoconstrictor Agents:
1. Norepinephrine & Epinephrine
2. Angiotensin
3. Vasopressin
4. Endothelin
2. Vasodilator Agents:
1. Bradikynin
2. Histamin
3. Effects of Ion & Other Chemical Factors
1. Calcium  vasoconstriction
2. Potasium  Vasodilatation
3. Magnesium  powerful vasodilatation
4. Hydrogen  vasodilatation
5. Acetate & Citrate  mild degree vasodilatation

10. Humoral Regulation of The Circulation
1. Vasoconstrictor Agents:
1. Norepinephrine & Epinephrine
2. Angiotensin
3. Vasopressin
4. Endothelin
2. Vasodilator Agents:
1. Bradikynin
2. Histamin
3. Effects of Ion & Other Chemical Factors
1. Calcium  vasoconstriction
2. Potasium  Vasodilatation
3. Magnesium  powerful vasodilatation
4. Hydrogen  vasodilatation
5. Acetate & Citrate  mild degree vasodilatation