BIOL 4510 Lecture : BIOL4510/KINE4510
Document Summary
In small single cell organisms or animals < 1 mm in diameter, movement of molecules can occur easily by diffusion or cell transport from the external environment. However, with larger multicellular organisms, diffusion is inadequate to provide the necessary nutrients, gases, salts or removal of waste. Required for cell-to-cell communication (transport hormones, deliver drugs etc) Major components of a circulatory system: a plumbing system: a pump, a conduit or vascular system, blood/fluids. This means that to a good approximation fluids/blood stay in the cardiovascular system although this is not quite true example given later. Small volume (5-10% of the body volume) Can alter velocity and distribution of blood flow rapidly. Heart: pressurizes blood to provide propulsion to force blood to flow in the pipes. Arteries or arterial system takes blood away from heart and distributes to body. Act as storage bin for high pressure blood. Capillaries: micro-vessels that are very small <5-6mm.
