Heart Structure & Function February 23, 2017 What questions do you have about the heart?

Cardiovascular System What is the major function of the cardiovascular system? To transport materials (oxygen, nutrients, wastes, hormones, immune components, heat, etc.) throughout the body What is the heart’s role in this system, and what are the other major components? Heart is the pump – supplies the force to move the blood. Blood carries the materials Vessels are roads and exchange surfaces

Heart Location & Size Nestled between the lungs, about the size of a fist, with apex pointed towards left hip and superior vena cava pointed towards right shoulder. The PMI refers to the place within 5th intercostal space where you can actually feel the apex of the heart - and best hear heart sounds

Heart Layers Pericarditis is inflammation of the pericardium. Pericarditis causes chest pains, has sudden onset, and usually resolves on its own. Many factors, including viruses, can cause.

Anterior view & Cardiac Circulation Cardiac vessels supply the heart muscle itself with blood. Heart disease (atherosclerosis) occurs when the aorta or cardiac arteries become clogged with fatty plaques.

Heart Anatomy (Frontal Section)

The Heart is a Double Pump The right side of the heart receives oxygen-poor blood from the body and pumps it to the lungs  pulmonary circulation The left side of the heart receives oxygen-rich blood from the lungs and pumps it to the body  systemic circulation

The heart has four chambers Each side has an atrium for collecting blood and a ventricle for pumping blood to the lungs or body Blood collects in atria while ventricles contract. Then, as ventricles relax, atria contract slightly and ventricles refill. Two sides of heart contract and relax simultaneously.

Flow of blood Use the diagram to determine the flow of blood through the heart and body. Vena cava     Vena cava R. atrium Pulmonary artery R. ventricle Lung vessels Pulmonary vein L. ventricle L. atrium aorta Body vessels

Comparison of four chambers The walls of the ventricles are much thicker than that of the atria? Why? Ventricles are more muscular, since they are the major pumps. Look at the diagram – how does the left ventricle differ from the right? What is the reason for the difference? Left ventricle is more muscular – needs to pump blood throughout entire body, while right ventricle just needs to send blood to lungs.

Heart valves ensure unidirectional flow Atrioventricular valves (tricuspid and mitral) hang open when the ventricles are filling forced closed when the ventricles contract anchored by chordae tendineae AV valves prevent backflow from __________________ to __________________ AV valves are closed by force of blood in ventricle during contraction; chordae tendineae prevent blowback

Heart valves ensure unidirectional flow Atrioventricular valves (tricuspid and mitral) hang open when the ventricles are filling forced closed when the ventricles contract anchored by chordae tendineae AV valves prevent backflow from ventricles to atria Semilunar valves (pulmonary and aortic) forced open when ventricles contract closed when ventricles relax AV valves are closed by force of blood in ventricle during contraction; chordae tendineae prevent blowback SL valves prevent backflow from ________ to__________

Heart valves ensure unidirectional flow Atrioventricular valves (tricuspid and mitral) hang open when the ventricles are filling forced closed when the ventricles contract anchored by chordae tendineae AV valves prevent backflow from ventricles to atria Semilunar valves (pulmonary and aortic) forced open when ventricles contract closed when ventricles relax AV valves are closed by force of blood in ventricle during contraction; chordae tendineae prevent blowback SL valves prevent backflow from arteries to ventricles

Heart valves ensure unidirectional flow In what stage of the cardiac cycle is the heart shown below? How do you know? Ventricles are contracting (in systole) because SL valves open (and AV valves close) when ventricles contract to force blood only towards arteries. Atria are relaxed (in diastole) Where else have you heard these words?

Heart Sounds Normal hearts make the sound: LUB-dup LUB-dup LUB-dup The “LUB” is caused by the closing of the AV valves. The “dup” is caused by the closing of the semilunar valves. Heart murmurs are abnormal heart sounds. In children, these are often benign. In adults, they usually indicate a problem – often, the failure of the valves to work properly. Mitral valve murmur For each murmur, have the kids identify what isn’t working, and why it would be a problem. Can also pause and ask them about diastole, systole. Aortic stenosis murmur Why is it a problem if the valves don’t function properly?

What parts didn’t we talk about yet? Ask students what didn’t I cover – fossa ovalis (remnant of foramen ovale – a hole from right to left atrium in fetal heart that bypasses helps bypass nonfunctioning lungs – and interventricular septum. Then, name parts / describe blood / exit ticket

Quick Review & Prelab 11 1 6 6 8 5 7 7 9 2 11 11 Ask students what didn’t I cover – fossa ovalis (remnant of foramen ovale – a hole from right to left atrium in fetal heart that bypasses helps bypass nonfunctioning lungs – and interventricular septum. Then, name parts / describe blood / exit ticket 5 3 4 10 12 13 14 15 16 1

Closure What questions did we answer today? What haven’t we answered? What new questions do you have?