Heart pumps over 2,500 gallons per day ¼ cup per beat beats per minute Over 60,000 miles of blood vessels

Fig. 20.1(TE Art) Systemic circuit Pulmonary circuit CO 2 O2O2 O2O2 artery vein artery

Fig. 20.2a(TE Art) 2nd rib Sternum Diaphragm

aorta esophagus T8

Pericardial cavity

Fibrous pericardium Myocardium Endocardium Parietal pericardium Visceral pericardium Epicardium = visceral pericardium + adipose

aorta Superior vena cava Inferior vena cava Right atrium Auricle of left atrium Right ventricle Left ventricle Pulmonary artery Anterior View Pulmonary veins

aorta Pulmonary artery Superior vena cava Inferior vena cava Left atrium Left ventricle Right ventricle Right atrium Pulmonary veins Posterior view

Chambers of the Heart 4 chambers –2 upper atria (atria = entry hall) (auricle = little ear) –2 lower ventricles (ventricles = little bellies) Auricle

Inferior vena cava Pulmonary artery Pulmonary veins Superior vena cava aorta R atrium R ventricle L ventricle L atrium

Pectinate muscle Papillary muscle Tendinous cords Trabeculae carneae Interventricular septum

Right atrium & ventricleLeft atrium & ventricle

Coronary sinus Coronary circulation L & R coronary artery = directly off aorta just distal to aortic valves Coronary sinus = drains into right atrium RCA LCA (Under auricle)

Fig Coronary artery disease (CAD) atherosclerosis

Myocardial infarction

By-pass Graft

Tricuspid valve Bicuspid or Mitral valve Pulmonary valve (semilunar valve) Aortic valve (semilunar valve)

Papillary muscle Chordae tendineae (tendinous cords)

Fig. 20.8a(TE Art) Pulmonary valve Aortic valve Openings to coronary arteries Left AV (bicuspid) valve Right AV (tricuspid) valve

Cardiac Cycle = 1 heartbeat Diastole = relaxation Systole = contraction

Atrioventricular Valves Open Ventricular diastole (atrial pressure > ventricle pressure)

Atrioventricular Valves Close Murmurs - mitral valve prolapse, stenosis, insufficiency Rheumatic fever Ventricle systole Ventricle pressure > atrial pressure A-V valves close preventing backflow of blood into atria

Aortic valves Pulmonary valves

1.What are the ventricles doing in A? 2.What are the ventricles doing in B? Valve Function Review A B

How does the heart beat?

Cardiac Cycle = 1 heartbeat AV valve closing = “lubb” Semilunar valves closing = “dupp”

Conduction System of Heart SA node – AV node – AV bundle of His (between ventricles) Heart block – arrhythmia - fibrillations

How does your heart rate change? Nervous control from the brain – sympathetic & parasympathetic Heart rate is also affected by hormones Drugs

Electrocardiogram---EKG EKG –Recording electrical currents in heart P wave – atrial contraction P to Q interval –time for impulse to travel from SA node to AV node QRS complex –ventricular contraction T wave – ventricular relaxation

Branching, intercalated discs with gap junctions, involuntary

Question for tomorrow – please think about this 1.What are the effects of heart failure in the right ventricle? 2.How is that different than heart failure in the left ventricle?