Don Jake Saunders
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MAS TER COpy MD -8 INSTRUCTIONAL GUIDE litRe Property of: Learning Resources Center Bio-Information Center ' . CREIGHTON UNIVERSITY 28th & Burt Street Omaha, NE 68178 DON JAKE SAUNDERS An Exclusive Product of Medical Plastics Laboratory, Inc. POST OFFICE BOX 38/ GATESVILLE, TEXAS 76528/ AC 817·865·7221 @ Copyright 1979 Medical Plastics t.aboratory. tnc. PREFACE This instructional guide was prepared for use with code numbers and the regular type numbers refer to the DON JAKE SAUNDERS HEART MODEL from Medical page numbers. Plastics laboratory, Inc., of Gatesville, Texas. Recognition and thanks goes to Dr. Robert Daley The purpose of this guide is to provide a compre of Ohio University, who has read the manuscript and hensive introduction to the anatomy of the human has given the benefit of his constructive criticism. heart for students of allied health professions as well as college and university students. One of the ob For the illustrations, I am Indebted to Mr. Danny jectives is to provide an introduction to the gross Smith of Medical Plastics laboratory, Inc. for his ex structure of the human heart using the DON JAKE cellent work. SAUNDERS HEART MODEL to illustrate the structural last but certainly not least, special recognition relationships. The other objective is to apply the must be given to the late DON JAKE SAUNDERS (1921 knowledge of the anatomy of the heart to heart 1976) of Medical Plastics laboratory, Inc., who sculpt function. This guide is not intended to be a detailed ed the heart model which bears his name. His exper or lengthy discussion of cardiac physiology. tise as a medical artist has lead to the development The numbers in parentheses in the text of this of a model which is second to none In accuracy and guide refer to the key code numbers on the model. detail. Two types of key code lists have been Included. The first lists all coded structures In numerical order while the second has the numbers grouped according to location on the model. The index lists all structures in alphabetical order. The bold faced numbers in the index refer to key Grover C. Ericson, Ph.D. CONTENTS Introduction. .................................................................. 1 Location " . .. .. .. .. .. .. .......................... .. .. 1 Pericardium. ................................................................ .. 1 External Anatomy , 2 HeartWalls .................................................................... 2 Circulation Through the Heart , 2 Blood Supply of the Heart. ...................................................... 2 Coronary Arteries. ...................................................... .. 2 Coronary Veins. ........................................................ .. 4 Internal Features of the Heart , 4 Right Atrium 4 RightVentrlcle .......................................................... .. 5 Left Atrium. ............................................................. .. 6 LeftVentrlcle ............................................................. 6 Interventricular Septum. ................................................. .. 6 HeartValves , 6 Atrioventricular Valves , 7 Aortic and Pulmonic Valves ' 7 Conduction System of the Heart , 8 Sinoatrial Node " ....................................................... .. 8 Atrioventricular Node. ................................................... .. 8 Atrioventricular Bundle and Branches. ....................................... 8 Innervation of the Heart. ...................................................... .. 9 Fetal Circulation. .............................................................. 9 Circulatory Changes at Birth. .................................................... 9 Electrocardiography ......................................................... .. 12 Systole and Diastole , 12 HeartSounds ................................................................ .. 13 Aorta and Its Branches , 13 Superior Vena Cava and Its Tributaries 14 Lymphatic System. ........................................................... .. 14 Regional Key Code. .......................................................... .. 16 Numerical Key Code. ........................................................ .. 18 Index 19 INTRODUCTION the mediastinum behind and a little to the left of the sternum, and above the middle portion of the dlo The heart is a muscular organ that acts as a phragm. The upper portion of the mediastinum con double pump; the right side receives deoxygenated tains the large blood vessels (great vessels) entering blood from the body and pumps It to the lungs while and leaving the heart. the left side receives the oxygenated blood from the lungs and pumps It to the rest of the body. The atria act as the receiving chambers of the heart and the ventricles as the pumping chambers. PERICARDIUM The heart begins to beat toward the end of the first month of embryonic development and must con A double-walled sac known as the pericardium tinue to beat for the duration of the Individual's life. In encloses the heart and the roots of the great vessels a lifetime of 70 years, the heart would beat over 21/2 (Figure 1). The outer fibrous layer (fibrous peri billion times and would pump over 41 million gallons cardium) Is attached below to the diaphragm. (158 million liters) of blood. If 'the heart were to stop Above It blends with the outer layers of the great ves for even a short time, Irreversible changes would oc sels. The fibrous pericardium serves to limit the move cur and death would quickly follow. ment of the heart. The Inner layer of the pericardium (serous pericardium) Is a closed sac. It lines the This remarkable muscular pump is about the size fibrous pericardium (and Is known as the parietal of the Individual's clenched fist. The DON JAKE serous pericardium) and Is reflected around the SAUNDERS HEART MODEl Is approximately three times roots of the great vessels and becomes continuous life size. with a layer (vlseral serous pericardium) on the sur face of the heart. Between the two serous layers Is the perlcardlal ccvltv, A small quantity of serous peri LOCATION cardlal flUId, secreted by the cells of the serous lay ers, fills the limited space of the cavity. This fluid per The heart is located In the central portion of the mits frictionless movement of the heart when It beats. thorax called the mediastinum, which divides the The DON JAKE SAUNDERS HEART MODEL presents the thorax Into left and right cavItIes (pleural cavities) anatomy of the heart with the fibrous and parietal that contain the lungs. It lies in the lower portion of serous pericardium removed. Fibrous Pericardium Parietal tSerous Pericardium Visceral Perlcardlal Cavity Fig. 1. Section through the thoracic cavity showing the organ ization of the serous and fibrous parts of the pe ri cardium. The pericardial cavity lies between tneperietet and visceral layers ofthe serous pericardium. EXTERNAL ANATOMY ventricles. When the ventricles contract a wringing action results and the ventricular walls come to When the model Is sitting on Its wooden base, It is gether similar to a squeezing fist and exert pressure In the correct anatomical position. In 'this position, on the blood Inside. the right border of the heart Is formed by the right atrium (96). The left border is formed by the left ven the outer layer of the heart, the epicardium, Is the tricle (2) and a small part of the auricle of the left visceral serous pericardium which was discussed atrium (4). previously. This layer Is firmly attached to the myo cardium except at the coronary and Interventricular The sternocostal (or anterior) surface of the heart sulci where blood vessels and sizable deposits of fat is comprised of the auricle of the rlght,atrlum (3) and intervene between the epicardium and myocar the right and left ventricles (1,2). The right auricle (3) dium. and right ventricle (1) are separated from one an other by the coronary (atrioventricular) sulcus or groove which contains, In addition to fat, the right CIRCULATION THROUGH THE HEART coronary artery (23). The coronary sulcus continues around the heart separating the atria (95,96) and the The direction of blood flow through 'the heart Is In ventricles (1,2). The right and left ventricles on the an dicated by blue and red arrows on the modal, The terior surface are separated by the anterior interven heart receives blood by way of the veins and pumps tricular sulcus which contains the anterior Interven it out through the arteries. Deoxygenated blood tricular (or anterior descending) artery (30) and great (blue arrows) from the upper part of the body, drains cardiac vein (31). into the superior vena cava (8) and then Into the right The heart is cone-shaped and the posterior sur atrium (96). Blood from the lower part of the body en face of the heart is the base of the cone. The base (or ters the right atrium (96) through the Inferior vena posterior surface) of the heart Is formed mainly by cava (60). From the right atrium (96), the blood passes the left atrium (95) Into which the pulmonary veins through 'the tricuspid valve (93) Into the right ventricle (50,51) open. The right atrium (96) also forms a small (i), When the ventricles contract, the blood Is pum portion of this surface. ped through the pulmonic valve (66) Into the pulmo nary trunk (6) and then to the lungs by way of the pul The apex of the heart lies opposite the base and Is monary arteries (12,49). The pulmonary trunk (6) and formed by the left ventricle (2). It points downward, arteries (12,49) transport