Скачать или смотреть Patterns of Circulation among different animal groups- Protochordates

#UniversityofLucknow
#Zoology
#CirculatorySystemInProtochordates
Multicellular organisms require a system for transporting nutrients throughout their bodies and removing waste products. Evolution in circulatory system has given rise to a complex network of vessels that reach all parts of the human body. The purpose of the circulation is to service the needs of the body tissues—to transport nutrients to the body tissues, to transport waste products away, to conduct hormones from one part of the body to another, and, in general, to maintain an appropriate environment in all the tissue fluids of the body for optimal survival and function of the cells. All the animals except the simplest unicellular have some type of circulatory system.