Blood

Learning objectives

To define the principal constituents of blood.
To illustrate that blood is set into motion by the heart, and that it circulates in only one direction.
To illustrate that blood is propelled by the heart, at the rhythm of the cardiac pulses. This is the circulatory system.

Blood is a complex fluid that transports a variety of molecules around the body. It carries diatomic Oxygen and the nutrients essential for the organism to function, but it also carries the wastes produced by these same organs (Carbon Dioxide, nitrogenous wastes).

It also carries the many molecules associated with the immune system, and diffuses hormones throughout the organism.