Mollusca
The majority of animals within the Mollusca phylum have an open circulatory system. The only animals that have a closed circulatory system and are in the Mollusca phylum are Cephalopods. In an open circulatory system, blood is not restricted to circulating within the blood vessels. Open circulatory systems, which have evolved through species, such as crustaceans, insects, mollusks, and other invertebrates, pump blood into a hemocoel with the blood extending back to the circulatory system betweens the various cells. Blood within a open circulatory system is pumped by a heart into the body cavities, where tissues are surrounded by blood. There are various animals that fit the requirements of the Mollusca Phylum.
The snail is one animal that makes up the Mollusca phylum. A Snail has an open circulatory system which means that blood is not restricted from traveling within the blood vessels. The heart of the snail is found on the left side of the body and is made up of one auricle and one ventricle. The ventricle pumps blood through an aortic trunk to all parts of the body through a group of arteries and capillaries. From the capillaries the blood flows into various spaces in the tissues called the hemocoel. From the hemocoel blood passes into the veins and back to the auricle. The blood present in snails contains a fused compound known as hemocyanin which purpose is to transports oxygen. Hemocyanin is similar to hemoglobin which is found in human blood.
Another Mollusca animal is the octopus. Octopuses differ from most Mollusca animals as they have a closed circulatory system. Octopuses have a single, main heart and two smaller hearts. The two smaller hearts are all necessary for keeping the blood pressure steady. Maintaining blood pressure is critical for octopuses, as that allows them to be active hunters and strong swimmers. The large heart is called a systemic heart and the two smaller hearts are located near the gills. These two smaller hearts pump blood to the gills where it dumps the waste and picks up oxygen. Then the two smaller hearts pump the oxygen-filled blood towards the main heart which pumps the blood to the rest of the body. They also have blue blood because they don't have hemoglobin, similar to humans. Instead, they have a protein called hemocyanin.
Slugs are also members of the Mollusca phylum. A slug is quite similar to a snail. Both have related circulatory system. The fluid that is transported through the circulatory system of a Slug is called hemolymph. Hemolymph is a fluid in the circulatory system and is similar to the fluids and cells making up both blood and interstitial fluid including water, proteins, and fats. Hemocyanin is present in the hemolymph as the respiratory pigment within the circulatory system of a Slug. Hemocyanins are respiratory proteins in the form of metalloproteins containing two copper atoms that reversibly bind a single oxygen molecule.
The snail is one animal that makes up the Mollusca phylum. A Snail has an open circulatory system which means that blood is not restricted from traveling within the blood vessels. The heart of the snail is found on the left side of the body and is made up of one auricle and one ventricle. The ventricle pumps blood through an aortic trunk to all parts of the body through a group of arteries and capillaries. From the capillaries the blood flows into various spaces in the tissues called the hemocoel. From the hemocoel blood passes into the veins and back to the auricle. The blood present in snails contains a fused compound known as hemocyanin which purpose is to transports oxygen. Hemocyanin is similar to hemoglobin which is found in human blood.
Another Mollusca animal is the octopus. Octopuses differ from most Mollusca animals as they have a closed circulatory system. Octopuses have a single, main heart and two smaller hearts. The two smaller hearts are all necessary for keeping the blood pressure steady. Maintaining blood pressure is critical for octopuses, as that allows them to be active hunters and strong swimmers. The large heart is called a systemic heart and the two smaller hearts are located near the gills. These two smaller hearts pump blood to the gills where it dumps the waste and picks up oxygen. Then the two smaller hearts pump the oxygen-filled blood towards the main heart which pumps the blood to the rest of the body. They also have blue blood because they don't have hemoglobin, similar to humans. Instead, they have a protein called hemocyanin.
Slugs are also members of the Mollusca phylum. A slug is quite similar to a snail. Both have related circulatory system. The fluid that is transported through the circulatory system of a Slug is called hemolymph. Hemolymph is a fluid in the circulatory system and is similar to the fluids and cells making up both blood and interstitial fluid including water, proteins, and fats. Hemocyanin is present in the hemolymph as the respiratory pigment within the circulatory system of a Slug. Hemocyanins are respiratory proteins in the form of metalloproteins containing two copper atoms that reversibly bind a single oxygen molecule.