The Circulatory system

• Multicellular organisms require transport systems to supply their cells and remove waste products.
• In humans, one of the functions of the circulatory system is to transport substances.
• The circulatory system includes the heart, blood vessels, and white blood cells.
• Development of cardiovascular disease can be evaluated through taking pulses and calculating blood flows.
• In single-celled organisms such as protists and small multicellular organisms, essential molecules will move to where they're needed by diffusion.
• Once an organism, such as a very early embryo, gets beyond a certain size, it needs a transport system to distribute essential molecules efficiently.
• Common features of transport systems include tubes or 'vessels' that carry materials from one part of the organism to another and make close contact with cells, such as those of exchange surfaces.
• Substances transported in the blood include oxygen, carbon dioxide, glucose, urea, and other substances.
• Oxygen is carried in red blood cells, dissolved substances are carried in the plasma, and white blood cells are part of the circulatory system.
• The circulatory system also controls the heart rate.
• Blood vessels are part of the circulatory system.
• The heart is part of the circulatory system.
• The circulatory system includes the control of the heart rate.
• The circulatory system includes blood vessels, the heart, and white blood cells.
• The circulatory system controls the heart rate.