CARDIOVASCULAR CARDIOVASCULAR SYSTEMSYSTEM

THE HEARTChapter 18

Physical CharacteristicsPhysical Characteristics

Located in the mediastinum between the lungs and behind the sternum

About the size of a clenched fist

Shaped like an inverted cone

Apex vs. Base

Coverings and LayersCoverings and Layers Covering Around the Heart

– Pericardium Fibrous pericardium Serous pericardium

– Parietal layer

– Visceral layer (epicardium)

– Serous fluid

Walls of the Heart– Epicardium– Myocardium– Endocardium

ChambersChambers

Atria– Right atrium– Left atrium– Interatrial septum– Fossa ovalis

Ventricles– Right ventricle– Left ventricle– Interventricular septum

Differences between the Differences between the VentriclesVentricles

ValvesValves Atrioventricular valves

– Tricuspid– Bicuspid (mitral)

Semilunar valves– Pulmonary semilunar– Aortic semilunar

Associated Structures– Chordae tendineae– Papillary muscles

ValvesValves

AV ValvesAV Valves

Semilunar ValvesSemilunar Valves

Heart Valve VideoHeart Valve Video

Microscopic AnatomyMicroscopic Anatomy

Microscopic AnatomyMicroscopic Anatomy

Blood FlowBlood Flow

Pulmonary CircuitSystemic CircuitCoronary CircuitVenous Drainage

Blood Flow Animation

Pulmonary vs. SystemicPulmonary vs. Systemic

Pulmonary CirculationPulmonary Circulation

Superior and inferior vena cava and coronary sinus

Right atrium Tricuspid Right Ventricle Pulmonary semilunar Pulmonary arteries Lungs

Systemic CirculationSystemic Circulation

Pulmonary veins Left atrium Bicuspid valve Left ventricle Aortic semilunar Systemic aorta Coronary artery

Coronary CirculationCoronary Circulation Left coronary artery

– Anterior interventricular artery

– Circumflex artery

Right coronary artery– Posterior

interventricular artery– Marginal artery

Arterial anatomoses

Posterior ViewPosterior View

Venous DrainageVenous Drainage

Superior vena cava Inferior vena cava Great cardiac vein Small cardiac vein Middle cardiac vein Coronary sinus

Posterior ViewPosterior View

Posterior ViewPosterior View

Anastomoses of Coronary Anastomoses of Coronary CirculationCirculation

Cardiac Conduction SystemsCardiac Conduction Systems

Intrinsic Cardiac Intrinsic Cardiac Conduction System AnimationConduction System Animation

Extrinsic Cardiac Extrinsic Cardiac Conduction SystemConduction System

Autonomic Innervation– Sympathetic nervous

system– Parasympathetic nervous

system

Cardiac PhysiologyCardiac Physiology

EKG

Heart Sounds

Cardiac Cycle

ElectrocardiographElectrocardiograph

EKG and ConductionEKG and Conduction

EKG AnimationEKG Animation

Abnormal ECGAbnormal ECG

Heart SoundsHeart Sounds

Auscultate Stethoscope Lub-dup, pause, lub-dup,

pause, etc Lub= AV valves closing Dup=Semilunar valves

closing

Cardiac Cycle AnimationCardiac Cycle Animation

Cardiac OutputCardiac Output

Cardiac output (CO) = the amount of blood pumped by each ventricle per minute

– CO = SV X HR– SV=“stroke volume” or the amount of blood

pumped by a ventricle in a single beat– HR=“heart rate” or number of beats per minute

Factors Affecting SVFactors Affecting SV

Factors Affecting SVFactors Affecting SV

ContractilityContractilityPositive Inotropic Agents

- Sympathetic NS

- Digitalis

- Glucagon (pancreas)

- Epinephrine

- Hypercalcemia

Negative Inotropic Agents- Hyperkalemia

- Hypocalcemia

- Cardiac hypoxia

- Cardiac hypercapnia

Factors Affecting HRFactors Affecting HR

Autonomic nervous systemHormones: epinephrine and thyroxineAge, gender, fitness, emotional stateBody temperatureIon concentrations in body fluidsBlood pressure

HomeostasisHomeostasis

Cardiac DisordersCardiac Disorders Valve disorders

– Heart murmur Stenosis Incompetent valve Mitral valve prolapse

– Rheumatic fever or Streptococcus infection– Sclerosis and thickening of valve flaps

Arrhythmias– Tachycardia– Bradycardia– Fibrillation– Heart block

Cardiac DisordersCardiac Disorders Other related heart problems

– Ischemia and hypoxia– Angina pectoralis – Myocardial infarction– Heart palpitation– Asystole– Myocarditis– Endocarditis– Cardiac tamponade– Pericarditis– Congenital defects– Congestive heart failure