Chapter 14 The Cardiovascular System 2 Introduction Cardiovascular

Chapter 14 The Cardiovascular System 2

Introduction • Cardiovascular system: heart, blood, and blood vessels • Cardiac muscle – Makes up bulk of heart – Provides force to pump blood • Function: transports blood 3

The Anatomy of the Heart 4

Introduction • Located in the mediastinum • Surrounded by pericardial sac – Fibrous pericardium: outer layer – Serous pericardium: inner layer 5

Introduction 6

The Layers of the Heart Wall • Epicardium: outermost layer • Pericardial cavity: separates epicardium and serous pericardium • Myocardium: middle muscular layer • Endocardium: lines the heart 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 Lower chambers: right and left ventricles Chambers separated internally by septum External separations – Coronary sulcus: separates atria and ventricles – Interventricular sulci: separate ventricles 10

The Great Vessels of the Heart • Superior vena cava – Receives blood from upper body • Inferior vena cava – Receives blood from lower body • Coronary sinus: drains blood from heart 11

The Great Vessels of the Heart (cont’d. ) • Pulmonary trunk: right and left artery – Carries deoxygenated blood to lungs • Pulmonary veins (four): return oxygenated blood to heart • Ascending aorta: carries oxygenated blood out to body – Aortic arch, descending thoracic, abdominal 12

The Great Vessels of the Heart (cont’d. ) 13

The Valves of the Heart • Atrioventricular – Tricuspid (three cusps) • Between right atrium and right ventricle – Bicuspid (two cusps) • Between left atrium and right ventricle – Cusps attach to ventricles by chordae tendineae 14

The Valves of the Heart (cont’d. ) • Semilunar – Pulmonary • Right ventricle • Pulmonary trunk exits the heart – Aortic • Left ventricle • Ascending aorta leaves the heart 15

The Valves of the Heart (cont’d. ) 16

Blood Flow through the Heart 17

Blood Flow through the Heart (cont’d. ) • Two atria contract while ventricles relax • Two ventricles contract while atria relax • Deoxygenated blood returns from body to right atrium • Sent to right ventricle, which pumps blood to lungs • Oxygenated blood returns to left atrium 18

Blood Flow through the Heart (cont’d. ) • Sent to left ventricle • Left ventricle sends blood to the body via the ascending aorta 19

Blood Flow through the Heart (cont’d. ) 20

The Conduction System of the Heart 21

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 22

The Conduction System of the Heart (cont’d. ) 23 23

A Cardiac Cycle 24

A Cardiac Cycle (cont’d. ) • One cycle – Atria contract / ventricles relax – Ventricles contract / atria relax • Systole: contraction phase • Diastole: relaxation phase 25

Some Major Blood Circulatory Routes 26

Some Major Blood Circulatory Routes (cont’d. ) • Systemic circulation – All blood leaving left ventricle (oxygenated) – All blood returning to right atrium (deoxygenated) – Subdivisions • Coronary circulation • Hepatic portal circulation 27

Some Major Blood Circulatory Routes (cont’d. ) • Pulmonary: blood flow to lungs for gas exchange • Cerebral: route to the brain • Fetal: between developing fetus and mother 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