BIO2242 Lecture Notes - Lecture 10: Aorta, Cardiac Output, Great Arteries
Document Summary
For sponges and diploblasts, the water in which they live provides the medium for transport. Water, propelled by ciliary, flagellar, or body movements, passes through channels or compartments to facilitate the movement of food, respiratory gases, and wastes. True circulatory system containing vessels through which blood moves are essential to animals so large or so active that diffusional processes alone cannot supply their oxygen needs. Flattened and leaflike acoelomate flatworms survive without a circulatory system because the distance of any body part from the surface is short; respiratory gases and metabolic wastes transfer by simple diffusion even though many are relatively large animals. A circulatory system having a full set of components pump, arterial distribution system, capillaries that interface with cells, various reservoir and return system. In earthworms, there are two main vessels, a dorsal vessel carrying blood anteriorly, and a ventral vessel delivering blood posteriorly throughout the body by way of segmental vessels and a dense tissue capillary network.
