1. BLOOD CIRCULATION
© 2016 Paul Billiet ODWS

2. Galen 2nd Century AD
Blood is formed all the time from food and drink that a human consumes
Blood flows to the heart where it passes from the left to the right side
Blood is consumed by the body or it passes out as wastes.
© 2016 Paul Billiet ODWS

3. William Harvey (1578-1657) The scientific approach to medicine
Took the bodies of sheep and pigs and drained out all their blood, which he measured
Calculated the volume of the ventricles of the animal’s heart
Measured the pulse
Conclusion: impossible for food and drink to replace all the blood leaving the heart.
© 2016 Paul Billiet ODWS

4. Blood circulates Systole is the active phase of the heart's movement
Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus 1628
Systole is the active phase of the heart's movement
Heart valves allow blood flow in only one direction
The ventricles contract together
The heart septum contains no gaps or perforations
The valves in the veins permit the blood to flow only in the direction of the heart.
© 2016 Paul Billiet ODWS

5. Marcello Malpighi 1661
Harvey suggested the existence of small capillaries between arteries and veins
1660s Anthony Leeuwenhoek & Robert Hook started to use microscopes on biological tissues
Malpighi observed blood capillaries vindicating Harvey.
© 2016 Paul Billiet ODWS
Frog lungs observed by Malpighi
C Hwa, & W C. Aird
American Journal of Physiology - Heart and Circulatory Physiology (2007) Vol. 293 no. 5,

6. Double circulatory system
LUNG TISSUE
Pulmonary circulation
Left Heart
Right Heart
Systemic circulation
BODY TISSUES
© 2016 Paul Billiet ODWS

7. CHARACTERISTICS VESSEL LUMEN DIAMETER /mm WALL THICKNESS NUMBERS
VOLUME
OF BLOOD
/ %
AORTA
25.0
2.0 1 2
ARTERIES
4.0
1.0
160 8
ARTERIOLES
0.03
0.02
57 million
CAPILLARIES
0.006
0.001
million 5
VENULES
0.002
1 300 million 54
VEINS
5.0
0.5
204
VENA CAVA
30.0
1.5
HEART - 12
PULMONARY CIRCULATION 18
© 2016 Paul Billiet ODWS

8. Pressure changes © 2016 Paul Billiet ODWS
© 2016 Paul Billiet ODWS

9. © 2016 Paul Billiet ODWS

10. Arteries © 2016 Paul Billiet ODWS
© 2016 Paul Billiet ODWS

11. Veins
© 2016 Paul Billiet
ODWS

12. Capillaries © 2016 Paul Billiet ODWS
© 2016 Paul Billiet ODWS

13. Blood vessels compared
Arteries
Capillaries
Veins
Take blood away from the heart
Exchange materials between the blood and the tissues
Return the blood to the heart
High pressure blood
Fast flowing blood
Pulses
HighLow pressure
Slow flowing
Low pressure blood
Slow flowing blood
Against gravity
Thick, muscular, elastic walls
Walls one cell thick (0.5 µm)
Diameter 6 µm
Very numerous so total xsectional area v. large
Muscular not very thick
Valves
Large internal diameter
© 2016 Paul Billiet ODWS