Physiology 206 Lecture 14 Outline of Last Lecture I mmHg II Ohm s Law III Poiseville s Law IV Regulation of cardiac output Outline of Current Lecture I Autoregulation of blood flow II Valves III Hypertension IV Pulmonary circulation V Heart failure VI Circulatory shock Current Lecture 2 17 14 Short term regulation of pressure Local flow regulation Muscle pumps Long term regulation of pressure Pulmonary circulation Hypertension When local concentration of oxygen is low smooth muscle relaxes When local concentration of oxygen is high smooth muscle constricts Arterioles have smooth muscle Autoregulation of blood flow o Exercise increases blood flow to a muscle Get extra blood from veins o Smooth muscle in arterioles relaxes causes more blood to flow and waste products to move These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o o Heart will pump out this extra blood Decreased blood flow to gastrointestinal system and blood flow to muscles increases blood flow to brain constant Pressure in veins is about 10mmHg There are valves in veins o Muscles squeeze veins and blood is forced back up to the heart Body fluid system for the long term regulation of pressure o Cardiac output arterial pressure renal loss of water ECF volume plasma volume venous return cardiac output Hypertension chronic increased blood pressure around 120mmHg o Around 90 is essential hypertension No one knows how it happened Pulmonary circulation o Flow pressure resistance o Pressure flow x resistance o Only goes to the lungs o Short vessels o Short distances o Low resistance low pressure around 30 mmHg o Apical parts of lungs get very little blood flow Exercise increases pressure Uses more lungs Heart failure o Venous return exceeds cardiac output o Blood leaks out results in swelling Fluid leaks into the ECF Occurs in the lungs Causes congestion Extra fluid in lungs Called congestive heart failure Circulatory shock o When arteriole pressure is too low to profuse tissue and prevent damage o Waste products are not being removed fast enough o Hypovolemic Reduced volume When plasma volume is reduced and venous return is decreasing Ex hemorrhage Cardiogenic o Inability of heart to pump o Can t maintain normal arteriole pressure Neurogenic o Results from extreme anxiety or pain o Massive parasympathetic output
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