BISC208 Lecture Notes - Lecture 20: Coronary Circulation, Coronary Artery Bypass Surgery, Heart Valve
Document Summary
Single cellular organism- uses diffusion/osmosis to effectively transport nutrients, gases, and water. Multicellular organism- also uses diffusion/osmosis but it is not efficient for larger distances and they require a system that specialized in transport of both nutrients/o2 and waste products/co2. Gastro-vascular cavities- functions as both the circulatory and digestive system of cnidarians (anemones, corals, jellyfish, hydra) Consists of only one opening to the outside. Open circulatory system- characterized by a fluid that is pumped by one or more contractile hearts into the body cavity of an animal. Arthropds and most mollusks, (hemolymph) liquid in blood vessels and interstitial fluid mingle in one large mixed compartment. Nutrients and wastes are exchanged by diffusion between hemolymph and body cells. Open ended vessels to the outside that returns hemolymph to the heart. Metabolically inexpensive, increased physical activity increases circulation efficiency. Cannot be selectively delivered to individual regions.