The Invertebrate Heart
In invertebrates that possess a circulatory system, the heart is typically a tube or small sac and pumps fluid that contains water and nutrients such as proteins, fats, and sugars. In insects, the "heart" is often called the dorsal tube and insect "blood" is almost always not oxygenated since they usually respirate (breathe) directly from their body surfaces (internal and external) to air. However, the hearts of some other arthropods (including spiders and crustaceans such as crabs and shrimp) and some other animals pump hemolymph, which contains the copper-based protein hemocyanin as an oxygen transporter similar to the iron-based hemoglobin in red blood cells found in vertebrates.
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Famous quotes containing the word heart:
“Women have their heads in their hearts. Man seems to have been destined for a superior being; as things are, I think women generally better creatures than men. They have weaker appetites and weaker intellects but much stronger affections. A man with a bad heart has been sometimes saved by a strong head; but a corrupt woman is lost forever.”
—Samuel Taylor Coleridge (1772–1834)