The heart is a pump that provides the energy to drive blood through the circulatory system.
Parity of the heart is understandable from the embryological point of view. Separation
of the left and right hearts ensures supply of well-oxygenated blood to the tissues.
Control of the heart rate is by the electrical conduction system.
THE BLOOD CIRCULATORY SYSTEM
The circulatory system is an illustration of the natural physical laws of equilibrium and
Blood circulation follows biophysical principles and is another illustration of the unity
of creation because physical and biological phenomena follow the same laws.
The efficiency of the heart’s energy conversion is 20%, better than many machines.
The circulatory system adjusts to changes. Blood flow to the skin increases in hot temperature
to release heat. During digestion more blood flows into the GIT. During exercise cardiac output increases ten-fold and work
done by the heart can increase 500-fold.
The lungs are the main organs of respiration. The lungs provide a big opportunity for exchange
between the internal and external environments.
The term respiration can be used in 2 different ways to mean ventilation or tissue respiration.
Coughing and sneezing expel irritants. In coughing the glottis is closed raising intra-ductal
pressure to 100mm of mercury. When the glottis is opened suddenly, a jet of air under high pressure is released accompanied
by the familiar sound of coughing. The glottis is not closed in sneezing but pressure still builds up.
Respiratory movements have been used over the millennia
as indicators of life. Death was pronounced when breathing stopped. This is no longer the situation because of modern life