BASICS OF THE HEART

1. BASICS OF THE HEART Katee Beaudry MS 2 – Penn State University College of Medicine kmatthews@hmc.psu.edu

2. Learning Objectives • To understand the basic anatomy of the heart. • To understand blood flow through the heart and lungs. • To understand the basic physiology of the heart. • To understand the basics of heart murmurs.

3. Vocabulary • Oxygenated blood – blood that has a lot of oxygen in it. • Deoxygenated blood – blood that does not have a lot of oxygen in it. • Systole – contraction • Diastole – relaxation • Arteries – carry oxygenated blood to tissues • Veins – carry deoxygenated blood from tissues • EXCEPTION – the pulmonary circulation

4. HEART ANATOMY

5. Right Atrium • Blood from the upper extremities and head empties into the right atrium through the Superior Vena Cava (SVC). • Blood from the lower extremities and abdomen empties into the right atrium through the Inferior Vena Cava (IVC). • Blood passes through the tricuspid valve to enter the right ventricle.

6. Right Ventricle • Blood enters the right ventricle through the tricuspid valve. • Blood leaves the right ventricle through the pulmonary semi-lunar valve and enters the pulmonary trunk

7. Pulmonary Circulation • The pulmonary trunk splits into the left and right pulmonary arteries. • These carry deoxygenated blood to the lungs. • The blood then passes through pulmonary capillaries, where the blood is oxygenated. • Oxygenated blood is carried back to the heart by 4 pulmonary veins.

8. Left Atrium • Oxygenated blood from the lungs enters the left ventricle via the pulmonary veins. • Blood passes through the bicuspid valve and enters the left ventricle.

9. Left Ventricle • Once oxygenated blood passes through the bicuspid valve it enters the left ventricle. • Oxygenated blood leaves the left ventricle through the aortic semi-lunar valve and enters the aorta. • The aorta takes oxygenated blood to the rest of the body.

10. Blood Flow Review • SVC and IVC to right atrium. • Tricuspid valve • Right ventricle • Pulmonary semi-lunar valve • Pulmonary Trunk • Pulmonary arteries • Pulmonary capillaries • Pulmonary veins • Left atrium • Bicuspid valve • Left ventricle • Aortic semi-lunar valve • Aorta

11. HEART WALL Endocardium – in contact with blood Myocardium – heart muscle (cardiac muscle) Epicardium – most outer layer PERICARDIUM Sac surrounding the heart. Visceral (on the heart) and parietal layers Secretes pericardial fluid to lubricate the heart. Heart Wall and Pericardium

12. Septa • Septa separate the right and left sides of the heart to make sure that oxygenated and deoxygenated blood do not mix. • Atrial Septum – separates the right and left atria (contains the fossa ovalis). • Ventricular Septum – separates the right and left ventricles.

13. Heart Valves • Review: • Tricuspid valve – between the right atrium and right ventricle. • Pulmonary semi-lunar valve – between the right ventricle and pulmonary trunk. • Bicuspid valve – between the left atrium and left ventricle. • Aortic semi-lunar valve – between the left ventricle and aorta

14. Function of Heart Valves • Valves prevent the backflow of blood in the heart. • The AV valves prevent blood from moving from the ventricles back into the atria. • The semi-lunar valves prevent blood from moving from arteries (aorta and pulmonary trunk) back into the ventricle.

15. 1st Heart Sound • 1st Heart Sound – referred to as “Lubb” • This sound occurs during ventricular systole (contraction). • The ventricles contract (generating pressure in the ventricles), which pushes open the semi-lunar valves. • When the ventricles contract, the AV (tricuspid and bicuspid) valves close due to the increased pressure in the ventricles as opposed to the atria. • The closing of the AV valves results in blood hitting them, causing the first heart sound.

16. 2nd Heart Sound • 2nd Heart Sound – referred to as “Dupp” • This sound occurs during ventricular diastole (relaxation). • When the ventricles relax, the pressure in the arteries is greater than that in the ventricles, and the semi-lunar valves close. • When the semi-lunar valves close, blood hits them causing the characteristic “Dupp” sound.

17. Murmurs • Murmurs are “extra” heart sounds heard. • They are due to insufficiencies in the heart valves causing leakage of blood. • There are two types of murmurs: • Sysolic murmurs • Diastolic murmurs

18. Systolic Murmurs • These murmurs occur during ventricular contraction. • The AV (tricuspid or bicuspid) valves are leaky and SOME blood flows backward, from the ventricles to the atria. • Lubb swooooosh Dupp

19. Diastolic Murmurs • These “extra” heart sounds occur during ventricular relaxation. • The semi-lunar valves are leaky and allow SOME blood to flow backwards, from the artery (aorta or pulmonary trunk) back into the ventricle. • Lubb Dupp Swooooooosh

20. Cardiac Physiology • The job of the heart is to move blood through the body. • Moves deoxygenated blood to the lungs to pick up oxygen and pushes oxygenated blood to the rest of the body tissues.

21. Cardiac Pathology • If there is a problem involving blood flow through the heart, less oxygen will get to the tissues that desperately need it. • The cardiovascular system will respond by increasing the pulse, blood pressure, respiratory rate, etc. • The individual will feel tired, have a lack of energy and will be short of breath with minimal exertion.

22. How to listen to someones heart…. All People Take Money A – aortic semi-lunar valve P – Pulmonic semi-lunar valve T – tricuspid valve M – mitral (bicuspid) valve Clinical Pearl!

23. So, How Well Do You Know the Heart? • What artery carries deoxygenated blood? • What structures separate the right and left sides of the heart? • When blood leaves the right side of the heart, where does it go? • What causes a heart murmur? • What does a systolic murmur sound like?

24. References • Lilly, L.S. Pathophysiology of heart disease. Lippincott Williams & Wolters Kluwer Business, 2007. P.39-43. • Martini, F.H. Fundamentals of anatomy and physiology. Pearson Benjamin Cummings. 2004. P. 682-716.