The Cardiac System SBC DC College Anatomy Bill Palmer

The Cardiac System

The Cardiovascular System PumpVessels – Transport blood

Blood Vessels Arteries –Away from heart Veins –Toward heart. Capillaries –Single cell layer –Interconnected networks called capillary beds.

Circulation of Blood Pulmonary circulation –Blood flow between heart and lungs Systemic circulation –Blood flow between heart and body

PULMONARY CIRCULATION SYSTEMIC CIRCULATION all tissues except lungs lungs

Human Heart Four muscular chambers: –Right atrium and right ventricle –Left atrium and left ventricle

Blood Flow Deoxygenated Blood  R. Atrium  Tricuspid Valve  R. Ventricle  Pulmonary Artery  Lungs  Oxygenated Blood  Pulmonary Vein  L. Atrium  Bicuspid Valve  Left Ventricle  Aorta  Systemic Circulation (body)  Capillaries  veins  Vena Cava

S. Vena cavaI. Vena cava tricuspid R. atrium R. ventricle bicuspid L. ventricle L. atrium Aorta Pulmonary a. Pulmonary v.

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Heart Sounds Lub dub –Lub sound of valves between the atria and ventricles closing –Dub sound of valves between ventricles and arteries

The Heart’s Own Blood Supply –Heart attack Supply to muscle reduced –Coronary arteries Plaques Myocardial infarction –Cells start to die –Fibrillation –muscle, unable to contract strongly, produces irregular rhythm

Anatomy 4 chambers –Receiving/filling chambers –Pumping chambers 4 valves –Atrio-ventricular valves –Semi-lunar valves Septum –Atrial –Ventricular

Anatomy Layers –Endocardium-Innermost layer of heart tissue –Myocardium-Middle layer of heart tissue –Epicardium-Outer layer of heart tissue –Pericardium-Outside covering or sac

Right Heart Anatomy Vena Cava –Superior (from head) –Inferior (from feet) Right Atrium Right Ventricle Pulmonary artery

Right Atrium Right border of the heart SVC – upper posterior IVC – lower posterior Intra atrial septum lies posterior Coronary sinus drains into RA

Right Ventricle Crescent shaped Inflow/outflow –Separated by ridge Surface – trabeculae Papillary muscles Cordae Tendinae

Left Heart Anatomy Pulmonary Veins Left Atrium Left Ventricle Aorta

Left Atrium Smaller than right atrium Thicker walls than right atrium 2 left & 2 right pulmonary veins Oval impression – Fossa Ovalis Atrial Appendage (longer & narrower)

Left Ventricle Oval shaped Larger than right Walls 3 X thicker than right –Greater pressure Smooth walls Papillary muscles Cordae tendinae

Valve Anatomy Atrio-ventricular valves Semi-lunar valves Lub-dub

Tricuspid valve 3 triangular shaped leaflets Names –Anterior –Septal –Posterior Papillary muscles & chordae tendinae are present but play a more important role in the high pressure chamber of LV

Mitral Valve 2 triangular leaflets 2 triangular leaflets Larger, thicker, stronger than tricuspid Larger, thicker, stronger than tricuspid Anterior leaflet (aortic or septal) Posterior leaflet (ventricular) Papillary muscle – contraction occurs during systole to shorten Cordae Tendinae –prevent MR during ventricular systole

Pulmonary valve 3 semi-lunar cusps 3 semi-lunar cusps Attached to wall of pulmonary trunk 2 cusps sit Anterior (right & left) 2 cusps sit Anterior (right & left) 1 cusp sits Posterior 1 cusp sits Posterior

Aortic valve Similar to pulmonary Leaflets - 3 semicircular scallops Like 3 pronged coronet Names –Right coronary cusp (anterior) –Left coronary cusp (left posterior) –Non-coronary cusp (right posterior)

Pericardium Outer sac – fibrous Inner, double layered sac – serous The most inner of these two serous layers actually forms the epicardium and is in direct contact with myocardium

Summary Anatomy of each chamber is designed for individual use Valves play important role in flow of blood through the heart Heart sounds – valve closure Highly efficient pump – predominantly left ventricle Allows ‘Dual circulation’ system – efficient oxygen uptake & distribution

Cardiac Diseases Mitral Valve Prolapse (MPV) – –Affects 6% of US Population – –Cusps of Mitral valve bulge back into L atrium when ventricle contracts – –Sounds like a click at end of V contraction then makes a murmur sound – –Pain, fatigue, palpitations, anxiety – –Can be damaged by Streptococcus bacteria – –MVP are susceptible to heart infection so must take antibiotics

Cardiac Diseases Angina Pectoris – –Blood clot blocks a coronary Artery branch – –Usually during physical activity – –Pain can spread through chest, arm, neck Myocardial Infarction (MI) – –Complete blockage of coronary vessel – –Robs heart muscle of O and cells die – –Heart Attack

Cardiac Diseases Arthrosclerosis – –Fatty deposits on arterial walls – –Usually cholesterol Arteriosclerosis – –Artery loses elasticity and may rupture=death – –Contributing factors Fatty diet Elevated Blood Pressure Tobacco Obesity Lack of exercise

Cardiac Diseases Treatment for Arteriosclerosis – –Percutaneous Transluminal Angioplasty Balloon – –Laser Angioplasty Laser destroys deposits – –Bypass Graft Surgery Vein from lower limb bypasses clot Vein must be put in backwards so valves do not impede blood flow – –Fibroblast Growth Factor Chemical causes new growth (angiogenesis)

Cardiac Diseases Hypertension – –High Blood Pressure-very common Kidney disease, High sodium, obesity, stress, arteriosclerosis L V must work harder to overcome pressure Heart enlarges and dies Can lead to cardiac thrombosis or Cerebral Vascular Accident (CVA) Treatment: – –Exercise – –Diet – –Control weight – –Control sodium intake

Cardiac Diseases Hypertension

Cardiac Diseases The Cardiovascular System Responds Well to Exercise – –Heart may enlarge 40% w/o cells dying – –Pulse may go as low at 25 bpm – –Slow steady build-up best. Snow shoveling kills old men – –Get pulse to 70-80% of theoretical maximum for 30 m 3X week – –TM = 220 minus age (220-18=202X70%=140BPM)

Heart Disease in US 1.Where in US is heart disease the worst? Best? 2.What factors may cause this?

Wrap up What are the structures of the cardiovascular system? What is the pathway of blood through the body? What are the components of blood? Functions? What are examples of blood vessels? Functions? What are the 2 types of circulation? What are the 4 major chambers of the heart? What is the pathway of blood through the heart? What causes the “lub” and “dub” of the heart sounds? How does blood get to the body with it’s oxygen?