The Cardiovascular System Chapter 14 The Cardiovascular System

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

The Anatomy of the Heart

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

The Layers of the Heart Wall Epicardium: outermost layer Pericardial cavity: separates epicardium and serous pericardium Myocardium: middle muscular layer Endocardium: lines the heart

The Layers of the Heart Wall (cont’d.)

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

The Chambers of the Heart (cont’d.)

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

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: oxygenated blood out to body Aortic arch, descending thoracic, abdominal

Four Chambers of the Heart and Great Vessels

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

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

Blood Flow Through the Heart

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

Blood Flow Through the Heart (cont’d.) Oxygenated blood returns to left atrium Sent to left ventricle Left ventricle sends blood to the body via the ascending aorta

The Conduction System of the Heart

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

The Conduction System of the Heart (cont’d.) Purkinje’s fibers: send impulse to myocardial cells

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

Animation – The Heart See the conduction system at work in the 3-D Heart animation. Click Here to Play Conduction System Animation

A Cardiac Cycle

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

Some Major Blood Circulatory Routes

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

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

Anatomy of Blood Vessels

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

Anatomy of Blood Vessels (cont’d.) Arteries: thicker and stronger than veins Arterioles: small arteries attach to capillaries Capillaries: gas nutrient and waste exchange

Anatomy of Blood Vessels (cont’d.) Venules: connect capillaries to veins Veins: less elastic than arteries, contain valves

Major Arteries and Veins of the Body

Ascending Aorta Branches Right and left coronary arteries branch off and supply the heart

Aortic Arch Branches 1st branch: brachiocephalic artery Right common carotid artery and right subclavian artery 2nd branch: left common carotid artery Left internal carotid artery and left external carotid artery

Aortic Arch Branches 3rd branch: left subclavian artery Vertebral artery, axillary artery, brachial artery and radial and ulnar arteries

Thoracic Aorta Branches 10 pairs of intercostal arteries Bronchial arteries Esophageal arteries Phrenic arteries

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

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

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

Veins Merging into the Superior Vena Cava (cont’d.) Internal jugular vein Right and left brachiocephalic veins Azygos vein

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

Veins Merging into the Inferior Vena Cava (cont’d.) Right and left gonadal veins Right and left renal veins Hepatic portal vein Right and left hepatic veins

Animation – Ventricular Fibrillation The following animation illustrates the seriousness of an ineffective quivering action of the ventricles of the heart, known as ventricular fibrillation Click Here to Play Ventricular Fibrillation Animation

Animation – Congestive Heart Failure Read about this condition in the Health Alert box on Congestive Heart Failure (CHF) in your textbook. Now watch the congestive heart failure animation. Click Here to Play Congestive Heart Failure Animation

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

Summary (cont’d.) Discussed the stages of the cardiac cycle Compared the anatomy of a vein, artery and capillary Named the major blood circulatory routes and blood vessels