Introduction Cardiovascular system heart blood and blood vessels
Introduction • Cardiovascular system: heart, blood, and blood vessels • Cardiac muscle – Makes up bulk of heart – Provides force to pump blood • Function: transports blood 2
The Anatomy of the Heart 3
Introduction • Located in the mediastinum • Surrounded by pericardial sac, which has two following parts: – Fibrous pericardium: outer layer, which is made of tough fibrous connective tissue and connects to the large blood vessels that enter and exit the heart. – Serous pericardium: inner layer, thin and delicate. 4
Introduction 5
The Layers of the Heart Wall • Epicardium/visceral pericardium: outermost layer, thin, transparent layer. • Pericardial cavity: separates epicardium and serous pericardium. This cavity contains a watery fluid called pericardial fluid, which reduces friction and erosion of tissue between these membranes as the heart expands and contracts during a cardiac cycle. • If an inflammation of the inner most layer of pericardial sac develops, it is known as pericarditis. • Myocardium: middle muscular layer, layer of cardiac muscle tissue. It is involuntary, striated, and branched. This layer is arranged in interlacing bundles and is the layer responsible for contraction of the heart. 6
• Endocardium: lines the third or innermost layer of the heart. Thin layer of connective tissue penetrated by tiny blood vessels and bundles of smooth muscle. It covers the valves of the heart and the chordae tendineae of the valves. 7
The Layers of the Heart Wall 8
The Layers of the Heart Wall (cont’d. ) 9
The Chambers of the Heart • Upper chambers: right and left atria. Each atrium has an external appendage called an auricle, names because of its similarity to the ear of a dog. Auricle increases the volume of the atrium. The two atria are separated from each other by an internal inter-atrial septum. • Lower chambers: right and left ventricles. They are internally separated from each other by interventricular septum. The irregular ridges and folds of the myocardium of the ventricles are called trabeculae carneae. • Chambers separated internally by septum • External separations by: – Coronary sulcus: separates atria and ventricles – Anterior and posterior Interventricular sulci: separate ventricles 10
The Great Vessels of the Heart • Right atrium receives blood from all parts of the body except the lungs. It receives this blood through three veins: superior/anterior vena cava( brings blood from upper parts of the body, head, neck, and arms), inferior vena cava/posterior vena cava( brings blood from the lower parts of the body, legs and abdomens) • Coronary sinus: drains blood from most of the vessels that supply the walls of the heart with blood. 11
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The Great Vessels of the Heart (cont’d. ) • The right ventricle pumps the blood into pulmonary trunk which splits into the right pulmonary artery and the left pulmonary artery, which carry the blood to the lungs. – They carry deoxygenated blood to lungs. • Pulmonary veins (four): return oxygenated blood to heart/left atrium. Then the blood is squeezed into the left ventricle. • Ascending aorta: carries oxygenated blood out to body, and to the coronary arteries ( which supply the walls of the heart with oxygenated blood), the arch of the aorta( which sends arteries to upper parts of the body). Descending thoracic aorta which becomes abdominal aorta. 13
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The Valves of the Heart • Atrioventricular – Tricuspid (three cusps) • Between right atrium and right ventricle – Bicuspid (two cusps)/atrioventricular valve/mitral valve • Between left atrium and right ventricle – Cusps attach to ventricles by chordae tendineae 15
The Valves of the Heart (cont’d. ) • Semilunar valves – Pulmonary semilunar valve • Right ventricle • Pulmonary trunk exits the heart – Aortic semilunar valve • Left ventricle • Ascending aorta leaves the heart 16
The Valves of the Heart (cont’d. ) 17
Blood Flow through the Heart 18
Blood Flow through the Heart (cont’d. ) • Deoxygenated blood enters right atrium via superior/inferior vena cava and coronary sinus. • Deoxygenated blood returns from body to right atrium • Sent to right ventricle passing tricuspid valve, which pumps blood to lungs via pulmonary trunk passing the pulmonary semilunar valve. • Left/right pulmonary arteries go to lungs to get oxygenated and return to heart in left atrium via left/right pulmonary veins. • Oxygenated blood returns to left atrium 19
Blood Flow through the Heart (cont’d. ) • Sent to left ventricle passing the bicuspid/mitral valve. • Left ventricle sends blood to the body via the ascending aorta passing the aortic semilunar valve. 20
Blood Flow through the Heart (cont’d. ) 21
The Conduction System of the Heart 22
The Conduction System of the Heart (cont’d. ) • Sinoatrial (SA) node: pacemaker; initiates impulse • Atrioventricular (AV) node: sends impulse to AV bundle • Bundle of His: sends impulses to both sides of system • Purkinje’s fibers: send impulse to myocardial cells 23
The Conduction System of the Heart (cont’d. ) 24 24
A Cardiac Cycle 25
A Cardiac Cycle (cont’d. ) • One cycle – Atria contract / ventricles relax – Ventricles contract / atria relax • Systole: contraction phase • Diastole: relaxation phase 26
Some Major Blood Circulatory Routes 27
Some Major Blood Circulatory Routes (cont’d. ) • Systemic circulation – All blood leaving left ventricle (oxygenated) – All blood returning to right atrium (deoxygenated) – Pulmonary: blood flow to lungs for gas exchange 28
Anatomy of Blood Vessels 29
Anatomy of Blood Vessels (cont’d. ) • Arteries and veins have three layers – Tunica intima: innermost layers – Tunica media: middle layer – Tunica adventitia: outer layer • Lumen: blood vessel cavity • Anastomosis: junction of blood vessels 30
Anatomy of Blood Vessels (cont’d. ) • Arteries: thicker and stronger than veins • Arterioles: small arteries attach to capillaries • Capillaries: gas nutrient and waste exchange • Venules: connect capillaries to veins • Veins: less elastic than arteries, contain valves 31
Anatomy of Blood Vessels (cont’d. ) 32
Major Arteries and Veins of the Body 33
Ascending Aorta Branches • Right and left coronary arteries branch off and supply the heart 34
Aortic Arch Branches • 1 st branch: brachiocephalic artery – Right common carotid artery and right subclavian artery • 2 nd branch: left common carotid artery – Left internal carotid artery and left external carotid artery • 3 rd branch: left subclavian artery – Vertebral artery, axillary artery, brachial artery, and radial and ulnar arteries 35
Thoracic Aorta Branches • • 10 pairs of intercostal arteries Bronchial arteries Esophageal arteries Phrenic arteries 36
Abdominal Aorta Branches • • • Celiac trunk Superior and inferior mesenteric arteries Right and left renal arteries Right and left gonadal arteries Lumbar arteries Right and left common iliac artery – Femoral artery 37
Abdominal Aorta Branches (cont’d. ) • Veins – Found closer to surface than arteries – Converge with • Superior vena cava • Inferior vena cava – Veins are often named identically to arteries 38
Veins Merging into the Superior Vena Cava • Radial and ulnar veins form brachial vein – Empties into axillary vein • • • Cephalic vein Basilic vein Subclavian vein Vertebral vein Internal jugular vein 39
Veins Merging into the Superior Vena Cava (cont’d. ) • Right and left brachiocephalic veins • Azygos vein 40
Veins Merging into the Inferior Vena Cava • Anterior and posterior tibial veins • Peroneal vein • Popliteal/femoral veins – External iliac vein • Great saphenous veins • Right and left common iliac veins • Right and left gonadal veins 41
Veins Merging into the Inferior Vena Cava (cont’d. ) • Right and left renal veins • Hepatic portal vein • Right and left hepatic veins 42
Summary • Named the layers of the heart wall • Named the chambers and valves of the heart • Described blood flow through the heart • Described the conduction system of the heart • Discussed the stages of the cardiac cycle 43
Summary (cont’d. ) • Compared the anatomy of a vein, artery and capillary • Named the major blood circulatory routes and blood vessels 44
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