Human Physiology BIOL 2213 Topic List for Chapter 12 Cardiovascular Physiology 12A 1 Know the design of the circulatory system Pulmonary loop Systemic loop o Carries oxygen poor blood to the lungs and back to the heart o Carries blood from the heart to the rest of the body Closed system leaks are bad What are the three main components of the circulatory system Heart blood and blood vessels What are the components of blood Fig 12 1 Plasma 55 Formed elements 45 o Buffy coat leukocytes and platelets o Erythrocytes hematocrit is basically all of the 45 Know the layout of the systemic and pulmonary circulation and the names of the major blood vessels feeding into and out of the heart and the names of chambers and important structures in the heart Fig 12 2 You will not be asked questions on these things specifically during the exam but you will need to know them to describe blood flow through the heart and factors affecting cardiac output etc 12A 2 Know the factors that affect blood flow through vessels and the relationships between flow pressure differences and resistance What factors affect resistance Pressure force exerted Flow volume moved Resistance how difficult it is for blood to flow between two points at any given pressure difference measure of friction that impedes flow o 3 things that contribute to resistance Blood viscosity affected by volume and of RBC Total blood vessel length how much tubing is needed longer means more friction Blood vessel diameter relaxed vessels decrease and constricted vessels increase resistance biggest contributor to minute to minute control of resistance Flow change in pressure resistance o If you increase resistance you decrease flow if the pressure stays the same 12A 3 Know the anatomy of the heart as shown in Fig 12 6 Know how the blood flows through the heart FIGURE 12 8 HELPFUL Know the different layers of tissue in the heart and what cell types comprise the heart Epicardium most superficial layer visceral layer of the serous pericardium Myocardium middle layer composed of cardiac muscle layer that contracts Endocardium inner layer continuous with the lining of the blood vessels entering and leaving the heart Cells endothelial cells located in endocardium Know how the autonomic nervous system innervates the heart and what the effects are of sympathetic and parasympathetic stimulation Sympathetic nervous system innervates whole heart and releases norepinephrine speeds up heart rate o Epinephrine does the same thing because norepinephrine has beta adrenergic receptors that allow epinephrine to bind too and have the same function Parasympathetic nervous system innervates the node cells and releases acetylcholine slows down heart rate come from vagus nerves o Has muscarinic receptor for Ach o Only innervates the atria and not the ventricles Know how blood is supplied to the tissues that comprises the heart Coronary arteries supply the myocardium with blood if clogged results in a heart attack Cardiac veins drain into the coronary sinus and empty into the right atrium 12B 2 Know the structures of the conducting system of the heart and how they function Sinoatrial node pacemaker of the heart Starts the excitation with a signal o Normal rate is about 75 signals From SA node there is a wave of depolarization through the intermodal pathway by gap junctions to the AV mode o There is a 1 second delay here so the atria can fully contract and and totally fill the ventricles before they have to contract Then wave of depolarization goes through AV bundle towards Purkinji fibers that go to the apex and then turn upwards Know the sequence of events in the conducting system of the heart during a typical heartbeat How does the action potential of a ventricular muscle cell Fig 12 12 differ from that of a Sinoatrial Node cell o Ventricular muscle cell Resting potential is 90 which is closer to K because the membrane is more permeable to K than Na o Spikes up because of Na entry and then slightly repolarizes but then plateaus because of Ca2 entry Once K exits there is a major repolarization until the cell is at resting again o SA node cell does not have a steady resting potential but undergoes a slow depolarization called pacemaker potential o Brings membrane to potential Na and Ca2 enter before threshold is reached o There is less of an increase than ventricular and repolarization occurs when K exits o Pacemaker currents bring cell to threshold more quickly than AV cell o Capable of automaticity the capacity for spontaneous rhythmic self excitation Fig 12 13 How do the differences relate to the function of those two cells Why is a refractory period present in ventricular muscle cells and why is that important o Refractory period present so that the atria can fully contract and fill the ventricles before they contract Know what an electrocardiogram is and what the different parts of the graph mean P QRS and T waves Be able to detect irregularities in and ECG Fig 12 14 12 15 and 12 16 o Electrocardiogram machine that measures electrical events in the heart o P atrial depolarization o QRS ventricular depolarization o T ventricular repolarization o Atrial repolarization is not shown because its occurs at the same time as the QRS complex o Irregularities o Partial block only every other atrial impulse is transmitted to the ventricles so there are too many P waves every second P wave is not followed by a QRS and T wave o Complete block the ventricles are being controlled by a node in the bundle of His that is very slow and the atria and ventricles are not synchronized at all Random waves 12B 3 Know the mechanical events that occur in the cardiac cycle and the names of the different events in the cycle Figs 12 18 and 12 19 o Cardiac cycle has 2 major phases systole and diastole o Systole time when the ventricles contracting and blood being ejected o Diastole ventricular relaxation and blood filling How does the pressure change in the different chambers and blood vessels as the cycle proceeds READ PAGE 367 370 o Aortic pressure start much higher than the other pressure and pressure is highest during ventricular contraction systole o Left ventricular pressure starts at same level as atrial pressure but drastically increases systole o Left atrial pressure starts low and stays relatively low How does the volume change o Left ventricular volume drastically decreases during systole and increases in diastole o End diastolic volume is the volume right at the point in between