IVMS-CV Comprehensive Overview Heart and Circulation

IVMS Heart and Circulation LectureAn Integrated Basic Medical Sciences Perspective and PresentationPrepared and Presented by: Marc Imhotep Cray, M.D.Image from: http://www.primalpictures.com/news.aspxCompanion:IVMSCardiovascularPharmacologyLectureLearning Objectives: http://www.usmle.org/Examinations/step1/content/cardiovascular.htmlCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 20092Functions of the Circulatory SystemTransportation:Respiratory:Transport 02and C02.Nutritive:Carry absorbed digestion products to liver and to tissues.Excretory:Carry metabolic wastes to kidneys to be excreted.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 20093Functions of the Circulatory System (continued)Regulation:Hormonal: Carry hormones to target tissues to produce their effects.Temperature: Divert blood to cool or warm the body.Protection:Blood clotting. Immune: Leukocytes, cytokines and complement act against pathogens.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 20094Components of Circulatory SystemCardiovascular System (CV):Heart: Pumping action creates pressure head needed to push blood through vessels.Blood vessels:Permits blood flow from heart to cells and back to the heart.Arteries, arterioles, capillaries, venules, veins.Lymphatic System:Lymphatic vessels transport interstitial fluid.Lymph nodes cleanse lymph prior to return in venous blood.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 20095Composition of Blood Plasma:Straw-colored liquid.Consists of H20 and dissolved solutes.Ions, metabolites, hormones, antibodies.Na+is the major solute of the plasma.Plasma proteins:Constitute 7-9% of plasma.Albumin: Accounts for 60-80% of plasma proteins.Provides the colloid osmotic pressure needed to draw H20 from interstitial fluid to capillaries.Maintains blood pressure.SEE: IVMS-CV Pharmacology-Drugs Affecting the BloodCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 20096Plasma proteins (continued):Globulins:a globulin:Transport lipids and fat soluble vitamins.b globulin: Transport lipids and fat soluble vitamins.g globulin: Antibodies that function in immunity.Fibrinogen:Constitutes 4% of plasma proteins.Important clotting factor.Converted into fibrin during the clotting process.Composition of the Blood (continued)Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 20097Serum:Fluid from clotted blood.Does not contain fibrinogen.Plasma volume:Number of regulatory mechanisms in the body maintain homeostasis of plasma volume.Osmoreceptors.ADH.Renin-angiotensin-aldosterone system.Composition of the Blood (continued)Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 20098ErythrocytesFlattened biconcave discs.Provide increased surface area through which gas can diffuse.Lack nuclei and mitochondria.Half-life ~ 120 days.Each RBC contains 280 million hemoglobin with 4 heme chains (contain iron).Removed from circulation by phagocytic cells in liver, spleen, and bone marrow.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 20099LeukocytesContain nuclei and mitochondria. Move in amoeboid fashion.Can squeeze through capillary walls (diapedesis).Almost invisible, so named after their staining properties.Granular leukocytes:Help detoxify foreign substances.Release heparin.Agranular leukocytes:Phagocytic.Produce antibodies.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200910Platelets (thrombocytes)Smallest of formed elements.Are fragments of megakaryocytes.Lack nuclei.Capable of amoeboid movement.Important in blood clotting:Constitute most of the mass of the clot.Release serotonin to vasoconstrict and reduce blood flow to area.Secrete growth factors:Maintain the integrity of blood vessel wall.Survive 5-9 days.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200911Blood Cells and PlateletsCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200912HematopoiesisUndifferentiated cells gradually differentiate to become stem cells, that form blood cells.Occurs in myeloid tissue (bone marrow of long bones) and lymphoid tissue.2 types of hematopoiesis:Erythropoiesis:Formation of RBCs.Leukopoiesis:Formation of WBCs.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200913ErythropoiesisActive process.2.5 million RBCs are produced every second.Primary regulator is erythropoietin.Binds to membrane receptors of cells that will become erythroblasts.Erythroblasts transform into normoblasts.Normoblasts lose their nuclei to become reticulocytes.Reticulocytes change into mature RBCs.Stimulates cell division. Old RBCs are destroyed in spleen and liver.Iron recycled back to myeloid tissue to be reused in hemoglobin production.Need iron, vitamin B12and folic acid for synthesis.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200914LeukopoiesisCytokines stimulate different types and stages of WBC production.Multipotent growth factor-1, interleukin-1, and interleukin-3:Stimulate development of different types of WBC cells.Granulocyte-colony stimulating factor (G-CSF):Stimulates development of neutrophils.Granulocyte-monocyte colony stimulating factor (GM-CSF):Simulates development of monocytes and eosinophils.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200915RBC Antigens and Blood TypingEach person’s blood type determines which antigens are present on their RBC surface.Major group of antigens of RBCs is the ABO system:Type AB:Both A and B antigens present.Type O:Neither A or B antigens present.Type A:Only A antigens present.Type B:Only B antigens present.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200916RBC Antigens and Blood Typing (continued)Each person inherits 2 genes that control the production of ABO groups.Type A:May have inherited A gene from each parent.May have inherited A gene from one parent and O gene from the other.Type B:May have inherited B gene from each parent.May have inherited B gene from one parent and O gene from the other parent.Type AB:Inherited the A gene from one parent and the B gene from the other parent.Type O:Inherited O gene from each parent.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200917Transfusion ReactionsIf blood types do not match, the recipient’s antibodies attach to donor’s RBCs and agglutinate.Type O:Universal donor:Lack A and B antigens.Recipient’s antibodies cannot agglutinate the donor’s RBCs.Type AB:Universal recipient:Lack the anti-A and anti-B antibodies.Cannot agglutinate donor’s RBCs.Insert fig. 13.6Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200918Rh FactorAnother group of antigens found on RBCs.Rh positive:Has Rho(D) antigens.Rh negative:Does not have Rho(D) antigens.Significant when Rh-mother gives birth to Rh+ baby.At birth, mother may become exposed to Rh+ blood of fetus.Mother at subsequent pregnancies may produce antibodies against the Rh factor.Erythroblastosis fetalis:Rh-mother produces antibodies, which cross placenta.Hemolysis of Rh+ RBCs in the fetus.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200919Blood ClottingFunction of platelets:Platelets normally repelled away from endothelial lining by prostacyclin (prostaglandin).Do not want to clot normal vessels.Damage to the endothelium wall:Exposes subendothelial tissue to the blood.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200920Blood Clotting (continued)Platelet release reaction:Endothelial cells secrete von Willebrand factor to cause platelets to adhere to collagen.When platelets stick to collagen, they degranulate as platelet secretory granules:Release ADP, serotonin and thromboxane A2.Serotonin and thromboxane A2stimulate vasoconstriction.ADP and thromboxane A2make other platelets “sticky.”Platelets adhere to collagen. Stimulates the platelet release reaction.Produce platelet plug.Strengthened by activation of plasma clotting factors. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200921Platelet plug strengthened by fibrin.Clot reaction:Contraction of the platelet mass forms a more compact plug.Conversion of fibrinogen to fibrin occurs.Conversion of fibrinogen to fibrin:Intrinsic Pathway:Initiated by exposure of blood to a negatively charged surface (collagen).This activates factor XII (protease), which activates other clotting factors.Ca2+and phospholipids convert prothrombin to thrombin.Thrombin converts fibrinogen to fibrin.Produces meshwork of insoluble fibrin polymers.Blood Clotting (continued)Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200922Blood Clotting (continued)Extrinsic pathway:Thromboplastin is not a part of the blood, so called extrinsic pathway.Damaged tissue releases thromboplastin.Thromboplastin initiates a short cut to formation of fibrin.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200923Blood Clotting (continued)Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200924Dissolution of ClotsActivated factor XII converts an inactive molecule into the active form (kallikrein). Kallikrein converts plasminogen to plasmin.Plasmin is an enzyme that digests the fibrin.Clot dissolution occurs.Anticoagulants:Heparin:Activates antithrombin III.Coumarin:Inhibits cellular activation of vitamin K.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200925Acid-Base Balance in the BloodBlood pH is maintained within a narrow range by lungs and kidneys.Normal pH of blood is 7.35 to 7.45.Some H+ is derived from carbonic acid.H20 + C02 H2C03 H++ HC03-Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200926Acid-Base Balance in the Blood (continued)Types of acids in the body:Volatile acids:Can leave solution and enter the atmosphere as a gas.Carbonic acid.H20 + C02 H2C03 H++ HC03-Nonvolatile acids:Acids that do not leave solution.Byproducts of aerobic metabolism, during anaerobic metabolism and during starvation.Sulfuric and phosphoric acid.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200927Buffer SystemsProvide or remove H+and stabilize the pH.Include weak acids that can donate H+and weak bases that can absorb H+.HC03-is the major buffer in the plasma.H++ HC03-H2C03Under normal conditions excessive H+ is eliminated in the urine.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200928Acid Base DisordersRespiratory acidosis:Hypoventilation.Accumulation of CO2.pH decreases.Respiratory alkalosis:Hyperventilation.Excessive loss of CO2.pH increases.Metabolic acidosis:Gain of fixed acid or loss of HCO3-.Plasma HCO3-decreases. pH decreases.Metabolic alkalosis:Loss of fixed acid or gain of HCO3-.Plasma HCO3-increases.pH increases.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200929pHNormal pH is obtained when the ratio of HCO3-to C02is 20:1.Henderson-Hasselbalch equation:pH = 6.1 + log = [HCO3-][0.03PC02]Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200930Pulmonary and Systemic CirculationsPulmonary circulation:Path of blood from right ventricle through the lungs and back to the heart.Systemic circulation:Oxygen-rich blood pumped to all organ systems to supply nutrients.Rate of blood flow through systemic circulation = flow rate through pulmonary circulation.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200931Atrioventricular and Semilunar ValvesAtria and ventricles are separated into 2 functional units by a sheet of connective tissue by AV (atrioventricular) valves.One way valves.Allow blood to flow from atria into the ventricles.At the origin of the pulmonary artery and aorta are semilunar valves.One way valves.Open during ventricular contraction.Opening and closing of valves occur as a result of pressure differences.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200932Atrioventricular and Semilunar ValvesCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200933Cardiac CycleSee: HyperheartRefers to the repeating pattern of contraction and relaxation of the heart.Systole:Phase of contraction.Diastole:Phase of relaxation.End-diastolic volume (EDV):Total volume of blood in the ventricles at the end of diastole.Stroke volume (SV):Amount of blood ejected from ventricles during systole.End-systolic volume (ESV):Amount of blood left in the ventricles at the end of systole.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200934Cardiac Cycle (continued)Step 1: Isovolumetric contraction:QRS just occurred.Contraction of the ventricle causes ventricular pressure to rise above atrial pressure.AV valves close.Ventricular pressure is less than aortic pressure.Semilunar valves are closed.Volume of blood in ventricle is EDV.Step 2: Ejection:Contraction of the ventricle causes ventricular pressure to rise above aortic pressure.Semilunar valves open.Ventricular pressure is greater than atrial pressure.AV valves are closed.Volume of blood ejected: SV.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200935Cardiac Cycle (continued)Step 3: T wave occurs:Ventricular pressure drops below aortic pressure.Step 4: Isovolumetric relaxation:Back pressure causes semilunar valves to close.AV valves are still closed.Volume of blood in the ventricle: ESV.Step 5: Rapid filling of ventricles:Ventricular pressure decreases below atrial pressure. AV valves open.Rapid ventricular filling occurs.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200936Cardiac CycleStep 6: Atrial systole:P wave occurs.Atrial contraction.Push 10-30% more blood into the ventricle.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200937Heart SoundsClosing of the AV and semilunar valves.Lub (first sound):Produced by closing of the AV valves during isovolumetric contraction.Dub (second sound):Produced by closing of the semilunar valves when pressure in the ventricles falls below pressure in the arteries.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200938Heart MurmursAbnormal heart sounds produced by abnormal patterns of blood flow in the heart.Defective heart valves:Valves become damaged by antibodies made in response to an infection, or congenital defects.Mitral stenosis:Mitral valve becomes thickened and calcified.Impairs blood flow from left atrium to left ventricle.Accumulation of blood in left ventricle may cause pulmonary HTN.Incompetent valves: Damage to papillary muscles.Valves do not close properly.Murmurs produced as blood regurgitates through valve flaps.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200939Heart MurmursSeptal defects:Usually congenital.Holes in septum between the left and right sides of the heart.May occur either in interatrial or interventricular septum.Blood passes from left to right.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200940Electrical Activity of the HeartSA node: Demonstrates automaticity:Functions as the pacemaker.Spontaneous depolarization (pacemaker potential):Spontaneous diffusion caused by diffusion of Ca2+through slow Ca2+ channels.Cells do not maintain a stable RMP.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200941Pacemaker APDepolarization:VG fast Ca2+channels open.Ca2+ diffuses inward.Opening of VG Na+channels may also contribute to the upshoot phase of the AP.Repolarization:VG K+channels open.K+diffuses outward.Ectopic pacemaker:Pacemaker other than SA node:If APs from SA node are prevented from reaching these areas, these cells will generate pacemaker potentials.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200942Myocardial APsMajority of myocardial cells have a RMP of –90 mV.SA node spreads APs to myocardial cells. When myocardial cell reaches threshold, these cells depolarize.Rapid upshoot occurs:VG Na+channels open.Inward diffusion of Na+.Plateau phase:Rapid reversal in membrane polarity to –15 mV.VG slow Ca2+channels open.Slow inward flow of Ca2+balances outflow of K+.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200943Myocardial APs(continued)Rapid repolarization:VG K+channels open.Rapid outward diffusion of K+.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200944Conducting Tissues of the HeartAPs spread through myocardial cells through gap junctions.Impulses cannot spread to ventricles directly because of fibrous tissue.Conduction pathway:SA node.AV node.Bundle of His.Purkinje fibers.Stimulation of Purkinje fibers cause both ventricles to contract simultaneously.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200945Conducting Tissues of the Heart (continued)Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200946Conduction of ImpulseAPs from SA node spread quickly at rate of 0.8 -1.0 m/sec.Time delay occurs as impulses pass through AV node. Slow conduction of 0.03 –0.05 m/sec.Impulse conduction increases as spread to Purkinje fibers at a velocity of 5.0 m/sec.Ventricular contraction begins 0.1–0.2 sec. after contraction of the atria.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200947Refractory PeriodsHeart contracts as syncytium.Contraction lasts almost 300 msec. Refractory periods last almost as long as contraction.Myocardial muscle cannot be stimulated to contract again until it has relaxed.Summation cannot occur.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200948Excitation-Contraction Coupling in Heart MuscleDepolarization of myocardial cell stimulates opening of VG Ca2+channels in sarcolema.Ca2+diffuses down gradient into cell.Stimulates opening of Ca2+-release channels in SR.Ca2+binds to troponin and stimulates contraction (same mechanisms as in skeletal muscle).During repolarization Ca2+actively transported out of the cell via a Na+-Ca2+-exchanger.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200949Electrocardiogram (ECG/EKG)The body is a good conductor of electricity.Tissue fluids have a high [ions] that move in response to potential differences.Electrocardiogram:Measure of the electrical activity of the heart per unit time.Potential differences generated by heart are conducted to body surface where they can be recorded on electrodes on the skin.Does NOT measurethe flow of blood through the heart.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200950ECG LeadsBipolar leads:Record voltage between electrodes placed on wrists and legs.Right leg is ground.Unipolar leads:Voltage is recorded between a single “exploratory electrode” placed on body and an electrode built into the electrocardiograph.Placed on right arm, left arm, left leg, and chest.Allow to view the changing pattern of electrical activity from different perspectives.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200951ECGP wave:Atrial depolarization.QRS complex: Ventricular depolarization.Atrial repolarization.T wave:Ventricular repolarization.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200952Correlation of ECG with Heart SoundsFirst heart sound:Produced immediately after QRS wave.Rise of intraventricular pressure causes AV valves to close.Second heart sound:Produced after T wave begins.Fall in intraventricular pressure causes semilunar valves to close.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200953Role is to direct the flow of blood from the heart to the capillaries, and back to the heart.Systemic CirculationArteries.Arterioles.Capillaries.Venules.Veins.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200954Blood VesselsWalls composed of 3 “tunics:”Tunica externa:Outer layer comprised of connective tissue.Tunica media:Middle layer composed of smooth muscle.Tunica interna:Innermost simple squamous endothelium.Basement membrane.Layer of elastin.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200955Blood Vessels (continued)Elastic arteries:Numerous layers of elastin fibers between smooth muscle.Expand when the pressure of the blood rises.Act as recoil system when ventricles relax.Muscular arteries:Are less elastic and have a thicker layer of smooth muscle.Diameter changes slightly as BP raises and falls.Arterioles:Contain highest % smooth muscle.Greatest pressure drop.Greatest resistance to flow.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200956Blood Vessels (continued)Most of the blood volume is contained in the venous system.Venules:Formed when capillaries unite.Very porous.Veins: Contain little smooth muscle or elastin.Capacitance vessels (blood reservoirs).Contain 1-way valves that ensure blood flow to the heart.Skeletal muscle pump and contraction of diaphragm:Aid in venous blood return of blood to the heart.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200957Types of CapillariesCapillaries:Smallest blood vessels.1 endothelial cell thick.Provide direct access to cells.Permits exchange of nutrients and wastes. Continuous:Adjacent endothelial cells tightly joined together. Intercellular channels that permit passage of molecules (other than proteins) between capillary blood and tissue fluid.Muscle, lungs, and adipose tissue.Fenestrated:Wide intercellular pores.Provides greater permeability.Kidneys, endocrine glands, and intestines.Discontinuous (sinusoidal):Have large, leaky capillaries.Liver, spleen, and bone marrow.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200958AtherosclerosisMost common form of arteriosclerosis (hardening of the arteries).Mechanism of plaque production:Begins as a result of damage to endothelial cell wall.HTN, smoking, high cholesterol, and diabetes.Cytokines are secreted by endothelium; platelets, macrophages, and lymphocytes.Attract more monocytes and lymphocytes.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200959Atherosclerosis (continued)Monocytes become macrophages.Engulf lipids and transform into foam cells.Smooth muscle cells synthesize connective tissue proteins.Smooth muscle cells migrate to tunica interna, and proliferate forming fibrous plaques.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200960Cholesterol and Plasma LipoproteinsHigh blood cholesterol associated with risk of atherosclerosis.Lipids are carried in the blood attached to protein carriers.Cholesterol is carried to the arteries by LDLs (low-density lipoproteins).LDLs are produced in the liver.LDLs are small protein-coated droplets of cholesterol, neutral fat, free fatty acids, and phospholipids.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200961Cholesterol and Plasma Lipoproteins (continued)Cells in various organs contain receptors for proteins in LDL.LDL protein attaches to receptors.The cell engulfs the LDL and utilizes cholesterol for different purposes.LDL is oxidized and contributes to:Endothelial cell injury.Migration of monocytes and lymphocytes to tunica interna.Conversion of monocytes to macrophages.Excessive cholesterol is released from the cells.Travel in the blood as HDLs (high-density lipoproteins), and removed by the liver.Artery walls do not have receptors for HDL.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200962Ischemic Heart DiseaseIschemia:Oxygen supply to tissue is deficient.Most common cause is atherosclerosis of coronary arteries.Increased [lactic acid] produced by anaerobic respiration.Angina pectoris:Substernal pain.Myocardial infarction (MI):Changes in T segment of ECG.Increased CPK and LDH.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200963Arrhythmias Detected on ECGArrhythmias:Abnormal heart rhythms.Flutter:Extremely rapid rates of excitation and contraction of atria or ventricles.Atrial flutter degenerates into atrial fibrillation.Fibrillation:Contractions of different groups of myocardial cells at different times.Coordination of pumping impossible.Ventricular fibrillation is life-threatening. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200964Arrhythmias Detected on ECG (continued)Bradycardia:HR slower < 60 beats/min.Tachycardia:HR > 100 beats/min.First–degree AV nodal block:Rate of impulse conduction through AV node exceeds 0.2 sec.P-R interval.Second-degree AV nodal block:AV node is damaged so that only 1 out of 2-4 atrial APs can pass to the ventricles.P wave without QRS.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200965Arrhythmias Detected on ECG (continued)Third-degree (complete) AV nodal block:None of the atrial waves can pass through the AV node.Ventricles paced by ectopic pacemaker.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200966Lymphatic System3 basic functions:Transports interstitial (tissue) fluid back to the blood.Transports absorbed fat from small intestine to the blood.Helps provide immunological defenses against pathogens.Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200967Lymphatic System (continued)Lymphatic capillaries:Closed-end tubules that form vast networks in intercellular spaces.Lymph:Fluid that enters the lymphatic capillaries.Lymph carried from lymph capillaries, to lymph ducts, and then to lymph nodes.Lymph nodes filter the lymph before returning it to the veins. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200968Cardiovascular Animations and Interactive TutorialsCardiovascular System Topicsby ADAM Basic Heart CirculationBristol-Myers Squibb Heart Structureby Nucleus Communications Heart functions and ProblemsCardiology Associates Electrocardiogram -ECG TechnicianNobel eMuseum Hyper heartby Knowlege Weavers The Arrhythma CenterHeartCenterOnline Cardiac Cell DeathSan Diego State University Prenatal HeartHeartCenterOnline Congenital Heart DiseaseHeartCenterOnline Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200969Cardiovascular Animations and Interactive Tutorials(2)Valvular Functions and DiseasesHeartCenterOnline Electro Cardio Gramby Knowlege Weavers Mammal Fetal Circulation by HHMI Cardiology -Visible Heartby HHMI The Electrocardiogram BasicsMcGill University Heart AnimationsScience Museum of Minnesota Operation Heart Transplantfrom PBS Interpeting an EKGEKG TutorialRnCeus Interactive Blaufuss Medical Multimedia Heart Valves Movieby Marcy Thomas at Wellesley Aninations of Common Heart Defects and RepairMiami Children's Hospital Cadaver Dissection of the Human HeartVirtual AutopsyHBO Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200970Free Useful PluginsAdobe Acrobat Reader-Document DistributionAdobe Flash Player-Web Animation -The leading rich client for Internet content and applications across the broadest range of platforms.Adobe Shockwave Player-With Adobe Shockwave Player, you can enjoy multimedia games and learning applications, using exciting new 3D technology.Adobe Authorware Player-With Adobe Authorware Web Player, you can experience online learning applications on the Web.QuickTime Player-Streaming/MultimediaCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.IVMS-Updated 200971Free Useful PluginsRealOne Player-Streaming/MultimediaMicrosoft Windows Media Player-Streaming/MultimediaMicrosoft Word Viewer-Viewing Word documents online (required if Word is not installed on resident computer; PC only)Microsoft PowerPoint Viewer-Viewing PowerPoint presentations online (required if PowerPoint is not installed on computer) Animated PowerPoint Add-in-needed if you do not have Office XPMicrosoft Excel Viewer-Viewing Excel documents online (required if Excel is not installed on resident computer; PC only)MDL Chimeinteractively displays 2D and 3D molecules directly in Web pages.