Chordata basic info
The phylum Chordata contains all animals that possess, at some point during their lives, a hollow nerve cord and a notochord, a flexible rod between the nerve cord and the digestive track. The phylum Chordata is an extremely diverse phylum, and the one most recognizable to most people. The phylum contains about 43,700 species.
SharkSharks have a two-chambered heart, with an atrium (also called the auricle) and a ventricle. The heart is an S-shaped tube that is located in the head region of the shark. The blood is pumped by the heart through the afferent branchial arteries (ventral aorta) to capillaries in the gills (where the blood is oxygenated). The blood then flows through efferent branchial arteries (paired dorsal aorta), then through the tissues of the body, and then back to heart in veins.
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SnakeThe three-chambered reptilian heart is composed of two atria, which receive blood from the lungs and body, and a large ventricle, which pumps blood into arteries. This heart is evolutionarily more basic than the mammalian four-chambered heart, but because of divisions and valves within the ventricle, the snake heart still functions as a four-chambered heart very similar to its mammalian counterparts.
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Frog |