Cardiovascular System I: Heart Anatomy and Physiology  Cardiovascular System Defined  Gross Anatomy of the Heart  Operation of Heart Valves  Cardiac Cycle and Heart Sounds  Cardiac Cycle and the EKG (ECG)  Electrical Conduction in the Heart

The Cardiovascular System Defined  What it is: A closed system of the heart and blood vessels oThe heart pumps blood oBlood vessels allow blood to circulate to all parts of the body  Function: Deliver oxygen and nutrients and to remove carbon dioxide and other waste products

Heart Gross Anatomy Location: Mediastinum of the thorax Size: As big as your fist Serous Membrane Coverings: 1.Epicardium (= visceral pericardium) innermost 2.Parietal pericardium outermost 3.Mediastinal pleura outside that

The Heart Wall: Three Layers = visceral pericardium Parietal Parietal Pericardium Visceral Pericardium (Epicardium) Myocardium Endocardium Exception: In the heart layers, peri- is outside of epi-

Corornal Section of Human Heart

Operation of Heart Valves Stenotic and Regurgitant Valve Conditions Heart sounds movie online AV valves Semilunar valves

Flow of Blood Through the Heart

Coronary Circulation: Blood Feeding the Heart Blockage of these vescles causes ischemia (lack of O 2 ), causing muscle death (myocardio infarct), and chest pain (angina pectoris)

Posterior View of Real Heart

Auscultation of Heart Sounds PCG: Phonocardiograph lub dup “S1” “S2” Heart sound talk Auscultation Sounds 1 Split S1 Split S2

The Heart: Conduction System  Intrinsic conduction system (nodal system) Heart muscle cells contract, without nerve impulses, in a regular, continuous way  Special tissue sets the pace 1.Sinoatrial node a.Pacemaker 2.Atrioventricular node 3.Atrioventricular bundle 4.Bundle branches 5.Purkinje fibers  Contraction is initiated by the sinoatrial node  Sequential stimulation occurs at other autorhythmic cells Exterior conduction Pacemaker with electrode in right ventricle

Filling of Heart Chambers – the Cardiac Cycle Figure 11.6  1. Atria contract simultaneously  2. Atria relax, then ventricles contract  Systole = contraction (can be subdivided into atrial and ventricular contraction but otherwise refers to ventricular systole)  Diastole = relaxation (ventricular)

Cardiac Cycle and Electrocardiography Cardiac cycle – events of one complete heart beat Mid-to-late diastole – blood flows into ventricles Ventricular systole – blood pressure builds before ventricle contracts, pushing out blood Early diastole – atria finish re-filling, ventricular pressure is low P Q R S T U Pressure, ECG, and Heart online EKG, Heart contractions, conduction online Note that an ECG does not show actual contractions but excitation and depolarizations

Heart Voltages and the ECG Arrhythmias Heart block

Hookups for the ECG