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.
Read more about this topic: Heart
Famous quotes containing the word heart:
“‘Tis not to see the world
As from a height, with rapt prophetic eyes,
And heart profoundly stirred;
And weep, and feel the fullness of the past,
The years that are not more.”
—Matthew Arnold (1822–1888)