Circulatory system of an Earthworm
Earthworm Dissection-PAP Bio- 3/12/14- Xiong, Lizi
Lumbricus terrestris
While earthworms are known for the ability to live after being cut into two, this is in fact, a myth. Earthworms have their entire digestive system running down the length of its body. It also has a simple, closed blood circulatory system. Earthworms have also been placed int eh suborder Lumbricina of the order Haplotaxida due to Theoretical cladistic studies. This may soon change.
Today's Objectives
Earthworm Life Cycle
Habitat
Predators
Evolution of Annelids
Earthworm Dissection
Internal Anatomy
External Anatomy
Circulatory system
Circulatory system at a glance
The earthworm has a closed circulatory system where the blood is recirculated throughout the body.Oxygen is absorbed directly from the soil. Earthworms do not have lungs. Oxygen is entered through the dorsal blood vessel where it travels to the five aortic arches (hearts). The esophagus pumps the blood to the lower, ventral blood vessel. Blood is then sent to all segments and organs in need of oxygen. A small blood vessel sends blood back from the ventral vessel to the dorsal vessel in each segment.
Five aortic arches: pump blood
Dorsal vessels: take blood back to front
Ventral vessels: take blood front to back
Capillaries: carries blood to proper areas and helps absorb nutrients
The circulatory system is one of the seven systems of the earthworm: respiratory, muscular, digestive, excretory, nervous, reproductive.