Architecture of the Circulation, Dr. D. Penney
Architecture of the circulation - Summary
Two pumps in series, each through own resistance in connecting vessels ('right heart/left heart', common septum and pacemaker).
Blood pressure higher on arterial side, lower on venous; thus arterial resistance greatest (ca. 40% in arterioles, 30% capillaries).
Symmetrical arrangement of components -
- - decreasing, then increasing diameter
- - decreasing, then increasing length
- - increasing, then decreasing number
- - increasing, then decreasing x - sectional area
- - increasing, then decreasing surface area
Pattern of number and surface area consistent with exchange function.
Pattern of x-sectional area dictates decrease, then increase in blood flow velocity (i.e. reciprocal relationship).
Blood volume greatest on venous side (55 - 65%), nil in capillaries.
Blood O2 concentration; high on arterial side, low on venous (a-v O2 difference).
Click to Return