all LOs cardiac

all LOs cardiac - 4.1 Organization of the Cardiovascular...

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4.1 – Organization of the Cardiovascular System Calculate the time of diffusion as a function of distance Describe the components of the cardiovascular system and their function— Heart: o Provides the motive force to pump the blood o Contraction of the heart muscle produces a pressure within the heart’s cavities o Contracts rhythmitically o Heart can beat automatically – normal resting heart rate is about 70 beats per minute o Unidirectional flow o Electrical system Each heart beat requires an action potential Coordinated contraction Begins at the apex of the heart and works its way upward Blood vessels: o Are hollow tubes that function primarily to channel the blood o Collectively called the vascular system o Five major types: large arteries, arterioles, capillaries, venules, and the major veins o Arteries always carry blood away from the heart and withstand high pressures o Venules and veins carry blood towards the heart and generally have a low pressure o Capillaries are about the same size as red blood cells o Allow close but indirect contact of the blood with the tissues, allowing for water, gas, and solute exchange between the blood and tissues o Four functions of the vascular system— Vessels transform pulsatile pressure into a continuous flow Ejection of blood from the heart produces a pulse of pressure in the major arteries As it goes through the vessels it eventually becomes smoothed out so the flow becomes more continuous at the level of tissues Vessels determine the distribution of flow to various organs Vessels are arranged in parallel for separate control of blood flow to each organ by controlling the caliber of the vessels leading to the organ Each organ is supplied by their own arteries
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Vessels determine the exchange of materials at the tissues Final exchange occurs through the vessel walls, principally by diffusion Exchange between blood and cells occurs mainly in the capillaries o walls of the capillaries are only a single cell thick so that the diffusion distance is small and the barrier for exchange is thin veins serve as a volume reservoir Blood: o Carries everything o Contains a variety of materials including water, salts, dissolved proteins, nutrients, and a variety of different cell types List the classes of important materials carried by the blood – Nutrients o Oxygen, glucose, amino acids, fatty acids, vitamins, minerals and salts, water, metabolites Waste products o CO2, urea, ammonia, uric acid, metabolites, detoxified environmental chemicals Heat o If heat is not dissipated, the internal core temperature of large animals will rise to high levels and thereby disrupt homeostasis o High intensity muscular activity produces a great deal of heat Chemical Signals o Endocrine hormones: chemical messengers that are released into the blood and which travel to distant target tissues o Paracrine secretions: released by cells; travel short distances to affect the
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all LOs cardiac - 4.1 Organization of the Cardiovascular...

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