BSC 2011 Lecture Notes - Lecture 16: Vasodilation, Vasoconstriction, Elastin
31 Oct 2016
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Larger organisms require a circulatory system to carry materials to and from cells: circulatory systems consist of: Open circulatory systems: seen in arthropods, molluscs, and some other invertebrates, the heart pumps fluid through the vessels into the cavities around the organs. Fluid is called hemolymph: low pressure system that requires less energy. Closed circulatory systems: blood vessels keep the circulatory fluid separate from the interstitial fluid, advantages: A higher pressure system which is more efficient in the delivery of nutrients and oxygen. Blood flow can be controlled by varying vessel diameter when traveling to a specific tissue. Blood is a connective tissue made up of: fluid plasma, erythrocytes. Fragments of cells that function in blood clotting. Red blood cells are the most numerous of the blood cells: they are produced in bone marrow, they have a life span of around 120 days, they function to transport oxygen around the body.
