The soil and food then moves through connecting tube called the esophagus. The crop is thin-walled and temporarily stores food and soil, and the muscular gizzard grinds food particles. Extracellular digestion and food absorption occurs in the intestine. The dorsal wall of the intestine is folded inward. The fold is called the typholsole and serves to increase the surface area for food absorption.
Food is distributed from the intestine to all the cells of the body by blood.
Five pairs of hearts surround the esophagus. These pump blood into large blood vessels. From the large blood vessels, the blood flows into smaller vessels, and eventually flows into capillaries. From capillaries, the blood flows into larger vessels and, eventually, back to the heart. This type of circulatory system in which blood is always contained within blood vessels or the hearts is called a closed circulatory system.