ertebrates - ertebrates, and a few invertebrates, have a...

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ertebrates, and a few invertebrates, have a closed circulatory system , shown in Figure 2. Closed circulatory systems (evolved in echinoderms and vertebrates) have the blood closed at all times within vessels of different size and wall thickness. In this type of system, blood is pumped by a heart through vessels, and does not normally fill body cavities. Blood flow is not sluggish. Hemoglobin causes vertebrate blood to turn red in the presence of oxygen; but more importantly hemoglobin molecules in blood cells transport oxygen. The human closed circulatory system is sometimes called the cardiovascular system. A secondary circulatory system, the lymphatic circulation , collects fluid and cells and returns them to the cardiovascular system. Vertebrate Cardiovascular System | Back to Top The vertebrate cardiovascular system includes a heart, which is a muscular pump that contracts to propel blood out to the body through arteries, and a series of blood vessels. The upper chamber of the heart, the
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ertebrates - ertebrates, and a few invertebrates, have a...

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