Anatomy of the Cardiovascular System Cardiovascular System Also

Anatomy of the Cardiovascular System

Cardiovascular System • Also circulatory system • Consists of: the heart, arteries, veins, capillaries

Heart • Four chamber muscular organ • Comparable to the size of a closed fist • Located in the mediastinum

Heart

Coverings of the Heart • Pericardium – loose fitting sac surrounding the heart – Fibrous pericardium – tough, loose-fitting, inelastic – Serous pericardium • Parietal layer: lines the inside of the fibrous pericardium • Visceral layer: adheres to outside of the heart – Pericardial space: between parietal and visceral layer • Filled with 10 -15 m. L of pericardial fluid • Decreases friction

Walls of the Heart • Epicardium – outer layer – Epicardium = serous pericardium • Myocardium – thick, contractile layer composed of cardiac muscle cells • Endocaridium – interior of cardiac wall

Walls of the Heart

Chambers of the Heart • Atria – two superior chambers – “Receiving chambers” – Blood from veins enters atria • Ventricles – two inferior chambers – “pumping chambers” – Separated by interventricular septum

Valves of the Heart • Permit blood flow in one direction during circulation • Atrioventricular valves (AV valves) – Also cuspid valves – Between atria and ventricles • Semilunar (SL valves) – Between ventricles and vessles

Chambers & Valves Trace the blood flow through the heart

Blood Supply to the Heart • After traveling through the capillaries of the heart, blood empties into the Right atrium via the vena cavas

Conduction System of the Heart • Sinoatrial Node (SA Node) – Pacemaker of the heart – 100 s of cells in the R atrium near the opening of the superior vena cava • Atrioventricular Node (AV Node) – Left lower border of R atrium

Types of Blood Vessels • Artery – carries oxygenated blood away from the heart – Arteriole: small artery – Precapillary sphincters: regulate the blood flow into capillaries

Types of Blood Vessels • Vein – carries unoxygenated blood towards the heart – Venules: small vein

Types of Blood Vessels

Types of Blood Vessels • Capillaries – arterial system switches to venous system – “primary exchange vessels” – Transport materials to and from the cells – Speed of blood flow decreases to increase contact time

Types of Blood Vessels

Structure of Blood Vessels • Tunica adventitia - outermost layer – Fibrous connective tissue – Holds vessels open; prevents tearing of vessels walls during body movements – Larger in veins than arteries • Tunica media – middle layer – Smooth muscle and elastic CT – Helps vessels constrict and dilate – Larger in arteries

Structure of Blood Vessels • Tunica intima – innermost layer – Composed of endothelium – Semilunar valves present in veins – One cell thick in capillaries

Circulatory Routes • Systemic Circulation – blood flow from the L ventricle to the body & back to the R atrium • Pulmonary Circulation – blood flow from the R ventricle to the lungs and back to the L atrium

Circulatory Routes

Aorta

Systemic Arteries • • Arch of aorta Subclavian (L and R) Brachiocephalic common carotid (L and R) Axillary (L and R) Brachial (L and R) Radial Ulnar • • Abdominal aorta Common iliac External iliac Femoral Popliteal Posterior tibial Anterior tibial Dorsal pedis

Systemic Veins • • • Superior vena cava Inferior vena cava External jugular Internal jugular Brachiocephalic (L and R) • Subclavian (L and R) • Cephalic • axillary • • • Basilic Median basilic Median cubital Common iliac External iliac Femoral Popliteal Great saphenous Small saphenous

Pericardium Disorders • Pericarditis – inflammation of the heart – Causes: trauma, viral or bacteria infection, tumor – Edema causes visceral and parietal layers to rub together = chest pain – Pus or blood build up in pericardial space – S/S • Pain with respirations or coughing, dyspnea, restlessness – Complications: Pericardial Effusion, Cardiac Tamponade – Treatment: • Antibiotics, pain meds, antiinflammatory meds, pericardiocentesis (Cardiac Tamponade)

Heart Valve Disorders • General Principles: – Congenital defect: decreased pumping efficiency – Incompetent valve leak: allows backflow into previous chamber – Stenosed valves: narrowed valve; slowing blood from out of chamber

Heart Valve Disorders • Mitral Valve Prolapse (MVP) – Flaps of mitral valve extend back into L atrium causes leaking – Mostly genetic basis – 1 in 20 people – S/S: most asymptomatic; chest pain, fatigue – Treatment: valvuloplasty

Mitral Valve Prolapse

Heart Valve Disorders • Aortic Regurgitation – Blood leaks back into L ventricle during ejection into the aorta – Volume overload in L ventricle, hypertrophy, dilation of L ventricle – Complications: myocaridal ischemia – Treatment: valvuloplasty

Myocardium Disorders • Atherosclerosis – Type of arteriosclerosis – Lipids build up on the inside of vessel walls calcify vessels hard & brittle – Risk factors: cigarette smoking, high fat/cholesterol diet, hypertension

Atherosclerosis

Myocardium Disorders • Myocardial Infarction – – “Heart Attack” Coronary thrombosis: clot Coronary embolism: mobilized clot Occlude coronary artery heart tissue deprived of oxygen cell death – S/S: • Angina pectoris – severe chest pain resulting from inadequate oxygen to myocardium – Treatment: Coronary Bypass Surgery • Veins are harvested from other areas of the body and used to bypass obstructions

Myocardium Disorders • Congestive Heart Failure (CHF) – “Left-sided Heart Failure” – Inability of the L ventricle to pump blood efficiently – Causes: myocardial infarction – S/S: decreased pumping pressure in systemic circulation; retained fluids • Can lead to congestion in pulmonary circulation pulmonary edema right-sided heart failure – Treatment: heart transplant

Congestive Heart Failure

Myocardium Disorders • Coronary Artery Disease (CAD) – Leading cause of death in US – General term to describe decreased blood flow to myocardium & associated side effects

Disorders of the Arteries • Arteriosclerosis – Arteries become occluded, weak and hardened – Complications: ischemia, necrosis, gangrene – Risk factors: age, diabetes, high fat/cholesterol diet, hypertension, smoking – Treatment: vasodilators, angioplasty, stent placement, bypass surgery – Complications: aneurysm

Angioplasty

Disorders of Veins • Varicose Veins – Enlarged veins caused by pooling – Results in varicosities or varices (“spider veins”) – Risk factors: standing for long periods • Semilunar valves widen more pooling – Treatment: compression stockings, surgical removal

Varicose Veins

Disorders of Veins • Phlebitis – vein inflammation – Causes: irritation by IV catheter • Thrombophlebitis – Deep vein thrombosis (DVT) – Phlebitis caused by a clot – S/S • Pain, redness, swelling – Complications • Pulmonary embolism

DVT

Pulmonary Embolism

Venous Stasis Ulcers • Result of chronic vein insufficiency • Lack of oxygen to peripheral tissues • Elevate leg & apply pressure • Irregular edges • “Aching” pain