Freshwater Leech (Macrobdella Decora)
There are over 6,500 species of leeches! Leeches inhabit a wide variety of habitats such as marshes, rivers, lakes, or ponds. Most leeches live in forest land, yet one-fifth of the leeches in the world live in water. The body of leeches is broken down into 34 segments that are either the color brown or black. Leeches have a similar nervous system, so they are used in studies of brain disorders. Leeches can also be used for medicinal purposes. The freshwater leech is believed to have evolved from the flatworm.
The freshwater leeches have an open circulatory system. This means that they do not contain blood vessels. Instead, blood flows through body cavities as it is being pumped by the heart. Blood in these leeches flow at a slow speed. Additionally, the blood flows at a low pressure because the leech lacks smooth muscles. There is direct contact between the body cells of the freshwater leech and its blood, which allows for a direct exchange of nutrients.
The freshwater leeches have an open circulatory system. This means that they do not contain blood vessels. Instead, blood flows through body cavities as it is being pumped by the heart. Blood in these leeches flow at a slow speed. Additionally, the blood flows at a low pressure because the leech lacks smooth muscles. There is direct contact between the body cells of the freshwater leech and its blood, which allows for a direct exchange of nutrients.