phylum chordata: We are among others
This phylum is made up of most vertebrates. They share a backbone and spinal column. Their circulatory systems are either single-looped or double looped. The blood is always contained within blood vessels of varying thickness and size.
- In snakes and other reptiles, there is a three-chambered heart composed of two atria, which receive blood from the lungs, body, and a large ventricle. This functions similarly to a normal four-chambered heart. Reptiles have a unique adaptation to their cardiovascular system (known as the renal portal system) where blood from the tail passes through the kidneys before circulating as normal.
- Human Being- Different veins and arteries supply blood to different parts of our body. A human heart is pictured below. Mammals and birds generally share very similar four-chambered heart structure, although varying greatly in size.
A shark's heart is fairly small in comparison to the rest of its body. It is a two-chambered tube, in a sort of S shape, containing an atrium and a ventricle. The blood is pumped from the heart to the gills (where the blood is oxygenated), and then to the rest of the body, through the ventral aorta and paired dorsal aorta. This enables the shark's internal body temperature to remain around 10-18 degrees Fahrenheit higher than the surrounding water, allowing the shark to work very well in colder, deeper waters where the predator can hunt for squid and certain fish. This is only possible because of the shark's mass and well-developed heat exchange within its circulatory system, allowing the warmer muscles to contract more smoothly.