DOCSLIB.ORG

The Cardiovascular System: the Heart: Part A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Cardiovascular System: the Heart: Part A PowerPoint® Lecture Slides prepared by Barbara Heard, Atlantic Cape Community College C H A P T E R 18 The Cardiovascular System: The Heart: Part A © Annie Leibovitz/Contact Press Images © 2013 Pearson Education, Inc. The Pulmonary and Systemic Circuits • Heart is transport system; two side-by-side pumps – Right side receives oxygen-poor blood from tissues • Pumps to lungs to get rid of CO2, pick up O2, via pulmonary circuit – Left side receives oxygenated blood from lungs • Pumps to body tissues via systemic circuit © 2013 Pearson Education, Inc. Figure 18.1 The systemic and pulmonary circuits. Capillary beds of lungs where gas exchange occurs Pulmonary Circuit Pulmonary arteries Pulmonary veins Aorta and branches Venae cavae Left atrium Left Right ventricle atrium Heart Right ventricle Systemic Circuit Capillary beds of all body tissues where Oxygen-rich, gas exchange occurs CO2-poor blood Oxygen-poor, CO2-rich blood © 2013 Pearson Education, Inc. Heart Anatomy • Approximately size of fist • Location: – In mediastinum between second rib and fifth intercostal space – On superior surface of diaphragm – Two-thirds of heart to left of midsternal line – Anterior to vertebral column, posterior to sternum PLAY Animation: Rotatable heart © 2013 Pearson Education, Inc. Heart Anatomy • Base (posterior surface) leans toward right shoulder • Apex points toward left hip • Apical impulse palpated between fifth and sixth ribs, just below left nipple © 2013 Pearson Education, Inc. Figure 18.2a Location of the heart in the mediastinum. Midsternal line 2nd rib Sternum Diaphragm Location of apical impulse © 2013 Pearson Education, Inc. Figure 18.2c Location of the heart in the mediastinum. Superior Aorta vena cava Parietal pleura (cut) Pulmonary Left lung trunk Pericardium (cut) Apex of heart Diaphragm © 2013 Pearson Education, Inc. Coverings of the Heart: Pericardium • Double-walled sac • Superficial fibrous pericardium – Protects, anchors to surrounding structures, and prevents overfilling © 2013 Pearson Education, Inc. Pericardium • Deep two-layered serous pericardium – Parietal layer lines internal surface of fibrous pericardium – Visceral layer (epicardium) on external surface of heart – Two layers separated by fluid-filled pericardial cavity (decreases friction) © 2013 Pearson Education, Inc. Figure 18.3 The pericardial layers and layers of the heart wall. Pulmonary trunk Fibrous pericardium Parietal layer of serous Pericardium pericardium Myocardium Pericardial cavity Epicardium (visceral layer of serous pericardium) Heart Myocardium wall Endocardium Heart chamber © 2013 Pearson Education, Inc. Homeostatic Imbalance • Pericarditis – Inflammation of pericardium – Roughens membrane surfaces pericardial friction rub (creaking sound) heard with stethoscope – Cardiac tamponade • Excess fluid sometimes compresses heart limited pumping ability © 2013 Pearson Education, Inc. Layers of the Heart Wall • Three layers of heart wall: – Epicardium – Myocardium – Endocardium • Epicardium – Visceral layer of serous pericardium © 2013 Pearson Education, Inc. Layers of the Heart Wall • Myocardium – Spiral bundles of contractile cardiac muscle cells – Cardiac skeleton: crisscrossing, interlacing layer of connective tissue • Anchors cardiac muscle fibers • Supports great vessels and valves • Limits spread of action potentials to specific paths © 2013 Pearson Education, Inc. Layers of the Heart Wall • Endocardium continuous with endothelial lining of blood vessels – Lines heart chambers; covers cardiac skeleton of valves © 2013 Pearson Education, Inc. Figure 18.3 The pericardial layers and layers of the heart wall. Pulmonary trunk Fibrous pericardium Parietal layer of serous Pericardium pericardium Myocardium Pericardial cavity Epicardium (visceral layer of serous pericardium) Heart Myocardium wall Endocardium Heart chamber © 2013 Pearson Education, Inc. Figure 18.4 The circular and spiral arrangement of cardiac muscle bundles in the myocardium of the heart. Cardiac muscle bundles © 2013 Pearson Education, Inc. Chambers • Four chambers: – Two superior atria – Two inferior ventricles • Interatrial septum – separates atria – Fossa ovalis – remnant of foramen ovale of fetal heart • Interventricular septum – separates ventricles © 2013 Pearson Education, Inc. Figure 18.5e Gross anatomy of the heart. Aorta Left pulmonary artery Superior vena cava Right pulmonary artery Left atrium Left pulmonary veins Pulmonary trunk Right atrium Mitral (bicuspid) valve Right pulmonary veins Fossa ovalis Aortic valve Pectinate muscles Pulmonary valve Tricuspid valve Right ventricle Left ventricle Chordae tendineae Papillary muscle Interventricular septum Trabeculae carneae Epicardium Inferior vena cava Myocardium Endocardium Frontal section © 2013 Pearson Education, Inc. Atria: The Receiving Chambers • Small, thin-walled • Contribute little to propulsion of blood • Three veins empty into right atrium: – Superior vena cava, inferior vena cava, coronary sinus • Four pulmonary veins empty into left atrium © 2013 Pearson Education, Inc. Ventricles: The Discharging Chambers • Most of the volume of heart • Right ventricle - most of anterior surface • Left ventricle – posteroinferior surface • Trabeculae carneae – irregular ridges of muscle on walls • Papillary muscles – anchor chordae tendineae © 2013 Pearson Education, Inc. Ventricles: The Discharging Chambers • Thicker walls than atria • Actual pumps of heart • Right ventricle – Pumps blood into pulmonary trunk • Left ventricle – Pumps blood into aorta (largest artery in body) © 2013 Pearson Education, Inc. Figure 18.5b Gross anatomy of the heart. Left common carotid artery Brachiocephalic trunk Left subclavian artery Superior vena cava Aortic arch Ligamentum arteriosum Right pulmonary artery Left pulmonary artery Ascending aorta Left pulmonary veins Pulmonary trunk Auricle of left atrium Right pulmonary veins Circumflex artery Right atrium Right coronary artery Left coronary artery (in coronary sulcus) (in coronary sulcus) Anterior cardiac vein Left ventricle Right ventricle Right marginal artery Great cardiac vein Anterior interventricular Small cardiac vein artery (in anterior Inferior vena cava interventricular sulcus) Apex Anterior view © 2013 Pearson Education, Inc. Figure 18.5a Gross anatomy of the heart. Aortic arch (fat covered) Pulmonary trunk Auricle of right atrium Auricle of left atrium Anterior interventricular artery Right ventricle Apex of heart (left ventricle) Anterior aspect (pericardium removed) © 2013 Pearson Education, Inc. Figure 18.5f Gross anatomy of the heart. Superior vena cava Ascending aorta (cut open) Pulmonary trunk Aortic valve Right ventricle anterior wall (retracted) Pulmonary valve Trabeculae carneae Interventricular septum (cut) Opening to right atrium Left ventricle Chordae tendineae Papillary muscles Right ventricle Photograph; view similar to (e) © 2013 Pearson Education, Inc. Heart Valves • Ensure unidirectional blood flow through heart • Open and close in response to pressure changes • Two atrioventricular (AV) valves – Prevent backflow into atria when ventricles contract – Tricuspid valve (right AV valve) – Mitral valve (left AV valve, bicuspid valve) – Chordae tendineae anchor cusps to papillary muscles • Hold valve flaps in closed position © 2013 Pearson Education, Inc. Figure 18.7 The atrioventricular (AV) valves. 1 Blood returning to the heart fills atria, pressing against the AV valves. Direction of The increased pressure forces AV blood flow valves open. Atrium Cusp of 2 As ventricles fill, AV valve flaps atrioventricular hang limply into ventricles. valve (open) Chordae 3 Atria contract, forcing additional tendineae blood into ventricles. Papillary Ventricle muscle AV valves open; atrial pressure greater than ventricular pressure Atrium Cusps of 1 Ventricles contract, forcing atrioventricular blood against AV valve cusps. valve (closed) 2 AV valves close. Blood in ventricle 3 Papillary muscles contract and chordae tendineae tighten, preventing valve flaps from everting into atria. AV valves closed; atrial pressure less than ventricular pressure © 2013 Pearson Education, Inc. Heart Valves • Two semilunar (SL) valves – Prevent backflow into ventricles when ventricles relax – Open and close in response to pressure changes – Aortic semilunar valve – Pulmonary semilunar valve © 2013 Pearson Education, Inc. Figure 18.8 The semilunar (SL) valves. Aorta Pulmonary trunk As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open. Semilunar valves open As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close. Semilunar valves closed © 2013 Pearson Education, Inc. Figure 18.6a Heart valves. Pulmonary valve Aortic valve Area of cutaway Mitral valve Tricuspid valve Myocardium Mitral (left atrioventricular) valve Tricuspid (right atrioventricular) valve Aortic valve Pulmonary valve Cardiac skeleton Anterior © 2013 Pearson Education, Inc. Figure 18.6b Heart valves. Pulmonary valve Aortic valve Area of cutaway Mitral valve Tricuspid valve Myocardium Mitral (left atrioventricular) valve Tricuspid (right atrioventricular) valve Aortic valve Pulmonary valve © 2013 Pearson Education, Inc. Figure 18.6c Heart valves. Pulmonary valve Aortic valve Area of cutaway Mitral valve Tricuspid valve Chordae tendineae attached Papillary to tricuspid valve flap muscle © 2013 Pearson Education, Inc. Figure 18.6d Heart valves. Pulmonary valve Aortic valve
Load more

Recommended publications
  • Te2, Part Iii
    TERMINOLOGIA EMBRYOLOGICA Second Edition International Embryological Terminology FIPAT The Federative International Programme for Anatomical Terminology A programme of the International Federation of Associations of Anatomists (IFAA) TE2, PART III Contents Caput V: Organogenesis Chapter 5: Organogenesis (continued) Systema respiratorium Respiratory system Systema urinarium Urinary system Systemata genitalia Genital systems Coeloma Coelom Glandulae endocrinae Endocrine glands Systema cardiovasculare Cardiovascular system Systema lymphoideum Lymphoid system Bibliographic Reference Citation: FIPAT. Terminologia Embryologica. 2nd ed. FIPAT.library.dal.ca. Federative International Programme for Anatomical Terminology, February 2017 Published pending approval by the General Assembly at the next Congress of IFAA (2019) Creative Commons License: The publication of Terminologia Embryologica is under a Creative Commons Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0) license The individual terms in this terminology are within the public domain. Statements about terms being part of this international standard terminology should use the above bibliographic reference to cite this terminology. The unaltered PDF files of this terminology may be freely copied and distributed by users. IFAA member societies are authorized to publish translations of this terminology. Authors of other works that might be considered derivative should write to the Chair of FIPAT for permission to publish a derivative work. Caput V: ORGANOGENESIS Chapter 5: ORGANOGENESIS
    [Show full text]
  • Cardiovascular System 9
    Chapter Cardiovascular System 9 Learning Outcomes On completion of this chapter, you will be able to: 1. State the description and primary functions of the organs/structures of the car- diovascular system. 2. Explain the circulation of blood through the chambers of the heart. 3. Identify and locate the commonly used sites for taking a pulse. 4. Explain blood pressure. 5. Recognize terminology included in the ICD-10-CM. 6. Analyze, build, spell, and pronounce medical words. 7. Comprehend the drugs highlighted in this chapter. 8. Describe diagnostic and laboratory tests related to the cardiovascular system. 9. Identify and define selected abbreviations. 10. Apply your acquired knowledge of medical terms by successfully completing the Practical Application exercise. 255 Anatomy and Physiology The cardiovascular (CV) system, also called the circulatory system, circulates blood to all parts of the body by the action of the heart. This process provides the body’s cells with oxygen and nutritive ele- ments and removes waste materials and carbon dioxide. The heart, a muscular pump, is the central organ of the system. It beats approximately 100,000 times each day, pumping roughly 8,000 liters of blood, enough to fill about 8,500 quart-sized milk cartons. Arteries, veins, and capillaries comprise the network of vessels that transport blood (fluid consisting of blood cells and plasma) throughout the body. Blood flows through the heart, to the lungs, back to the heart, and on to the various body parts. Table 9.1 provides an at-a-glance look at the cardiovascular system. Figure 9.1 shows a schematic overview of the cardiovascular system.
    [Show full text]
  • Chapter Xi the Circulatory System and Blood
    CHAPTER XI THE CIRCULATORY SYSTEM AND BLOOD Page General characterlstlcs______ __ __ _ __ __ __ __ __ __ _ 239 of these organs are independent of the beating of The pericardium ___ __ __ __ 239 the principal heart, and their primary function is The heart. _____ __ __ 240 Physiology of the heart.______________________________________________ 242 to oscillate the blood within the pallial sinuses. Automatism of heart beat. _ 242 The pacemaker system_ 245 THE PERICARDIUM Methods of study of heart beat_____________________________________ 247 Frequency of beat___ __ __ _ 248 Extracardlac regulatlon____ __ __ _ 250 The heart is located in the pericardium, a thin­ Effects of mineral salts and drugs___________________________________ 251 Blood vessels_ __ ___ _ 253 walled chamber between the visceral mass and the The arterial system______ __ __ ___ __ __ __ __ __ 253 adductor muscle (fig. 71). In a live oyster the The venous system_________________________________________________ 254 location of the heart is indicated by the throbbing The accessory heart._____________ 258 The blood______ __ __ __ __ __ __ __ 259 of the wall of the pericardium on the left side. Color of blood_ __ __ 261 Here the pericardium wall lies directly under the The hyaline cells___________________________________________________ 261 The granular cells .______________________________________ 262 shell. On the right side the promyal chamber Specific gravity of blood____________________________________________ 265 extends down over the heart region and the mantle Serology ___ __________ __________________ ____ __ ______________________ 265 Bibliography __ __ __ __ __ __ __ 266 separates the pericardium wall from the shell. The cavity in which the heart is lodged is slightly A heart, arteries, veins, and open sinuses form asymmetrical; on the right side it extends farther the circulatory system of oysters and other bi­ along the anterior part of the adductor muscle valves.
    [Show full text]
  • A Direct Examination of Papillary Muscle Function in the Canine Left Ventricle
    Loyola University Chicago Loyola eCommons Master's Theses Theses and Dissertations 1968 A Direct Examination of Papillary Muscle Function in the Canine Left Ventricle Robert Emmet Cronin Loyola University Chicago Follow this and additional works at: https://ecommons.luc.edu/luc_theses Part of the Medicine and Health Sciences Commons Recommended Citation Cronin, Robert Emmet, "A Direct Examination of Papillary Muscle Function in the Canine Left Ventricle" (1968). Master's Theses. 2081. https://ecommons.luc.edu/luc_theses/2081 This Thesis is brought to you for free and open access by the Theses and Dissertations at Loyola eCommons. It has been accepted for inclusion in Master's Theses by an authorized administrator of Loyola eCommons. For more information, please contact [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. Copyright © 1968 Robert Emmet Cronin A DIRECT EXAMINATION OF PAPILLARY MUSCLE FUNCTION IN THE CANINE LEFT VENTRICLE by Robert Emmet Cronin A Thesis Submitted to the Faculty of the Graduate School of Loyola University in Partial Fulfillment of the Requirements for the Degree of Master of Science June 1968 LIFE Robert E. Cronin was born in Chicago, Illinois, on March 26, 1942. He attended St. Ignatius High School, in Chicago, Illinois, and then Holy Cross College in Worcester, Massachusetts, where he received his Bachelor of Arts degree in 1964. Since September, 1964, he has been a medical student at Loyola Uni­ versity, Stritch School of Medicine, and will receive his M.D. degree in June, 1968. For the past three years he has been enrolled in the combined Master of Science - Medical .
    [Show full text]
  • Venous Circulation of the Human Cardiac Conduction System
    Br Heart J: first published as 10.1136/hrt.42.5.508 on 1 November 1979. Downloaded from British Heart J7ournal, 1979, 42, 508-513 Venous circulation of the human cardiac conduction system 0. ELI SKA AND M. ELI KoVA From the Department of Anatomy, Faculty of Medicine, Prague 2, U nemocnice 3, Czechoslovakia summARY The venous bed ofthe sinuatrial node in 25 human hearts and the atrioventricular conduction system in 50 human hearts were investigated after injection into different veins of the heart. Blood is drained from the sinuatrial node in two directions; that from the intermediate and upper parts of the node blood is directed upwards, draining into the junctional area ofthe superior vena cava with the right atrium. From the intermediate and the lower parts ofthe node the venous return is directed downwards, draining directly into the right atrium between the musculi pectinati. The venous return from the ventricular conduction system is drained by three routes. The main route from the atrioventricular node and the atrioventricular bundle passes into the thebesian vein, which opened in 78 per cent of the cases studied into the right atrium next to the coronary sinus. The other route from the node and bundle is via a vein which accompanies the atrioventricular nodal artery, draining eventually into the middle cardiac vein. The third route takes venous blood from the lower part ofthe atrioventricular bundle and is drained to the tributaries of the great cardiac vein, interconnecting with the branches of the above two veins. The venous return from the ventricular bundle-branches is drained into the oblique septal veins.
    [Show full text]
  • Cellular and Molecular Mechanisms of Functional Hierarchy of Pacemaker Clusters in the Sinoatrial Node: New Insights Into Sick Sinus Syndrome
    Journal of Cardiovascular Development and Disease Review Cellular and Molecular Mechanisms of Functional Hierarchy of Pacemaker Clusters in the Sinoatrial Node: New Insights into Sick Sinus Syndrome Di Lang and Alexey V. Glukhov * Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; [email protected] * Correspondence: [email protected] Abstract: The sinoatrial node (SAN), the primary pacemaker of the heart, consists of a heterogeneous population of specialized cardiac myocytes that can spontaneously produce action potentials, generat- ing the rhythm of the heart and coordinating heart contractions. Spontaneous beating can be observed from very early embryonic stage and under a series of genetic programing, the complex heteroge- neous SAN cells are formed with specific biomarker proteins and generate robust automaticity. The SAN is capable to adjust its pacemaking rate in response to environmental and autonomic changes to regulate the heart’s performance and maintain physiological needs of the body. Importantly, the origin of the action potential in the SAN is not static, but rather dynamically changes according to the prevailing conditions. Changes in the heart rate are associated with a shift of the leading pacemaker location within the SAN and accompanied by alterations in P wave morphology and PQ interval on ECG. Pacemaker shift occurs in response to different interventions: neurohormonal modulation, cardiac glycosides, pharmacological agents, mechanical stretch, a change in temperature, Citation: Lang, D.; Glukhov, A.V. and a change in extracellular electrolyte concentrations. It was linked with the presence of distinct Cellular and Molecular Mechanisms anatomically and functionally defined intranodal pacemaker clusters that are responsible for the of Functional Hierarchy of Pacemaker Clusters in the Sinoatrial Node: New generation of the heart rhythm at different rates.
    [Show full text]
  • Vocabulario De Morfoloxía, Anatomía E Citoloxía Veterinaria
    Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) Servizo de Normalización Lingüística Universidade de Santiago de Compostela COLECCIÓN VOCABULARIOS TEMÁTICOS N.º 4 SERVIZO DE NORMALIZACIÓN LINGÜÍSTICA Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) 2008 UNIVERSIDADE DE SANTIAGO DE COMPOSTELA VOCABULARIO de morfoloxía, anatomía e citoloxía veterinaria : (galego-español- inglés) / coordinador Xusto A. Rodríguez Río, Servizo de Normalización Lingüística ; autores Matilde Lombardero Fernández ... [et al.]. – Santiago de Compostela : Universidade de Santiago de Compostela, Servizo de Publicacións e Intercambio Científico, 2008. – 369 p. ; 21 cm. – (Vocabularios temáticos ; 4). - D.L. C 2458-2008. – ISBN 978-84-9887-018-3 1.Medicina �������������������������������������������������������������������������veterinaria-Diccionarios�������������������������������������������������. 2.Galego (Lingua)-Glosarios, vocabularios, etc. políglotas. I.Lombardero Fernández, Matilde. II.Rodríguez Rio, Xusto A. coord. III. Universidade de Santiago de Compostela. Servizo de Normalización Lingüística, coord. IV.Universidade de Santiago de Compostela. Servizo de Publicacións e Intercambio Científico, ed. V.Serie. 591.4(038)=699=60=20 Coordinador Xusto A. Rodríguez Río (Área de Terminoloxía. Servizo de Normalización Lingüística. Universidade de Santiago de Compostela) Autoras/res Matilde Lombardero Fernández (doutora en Veterinaria e profesora do Departamento de Anatomía e Produción Animal.
    [Show full text]
  • Abnormalities Caused by Left Bundle Branch Block - Print Article - JAAPA
    Marquette University e-Publications@Marquette Physician Assistant Studies Faculty Research and Physician Assistant Studies, Department Publications 12-17-2010 Abnormalities Caused by Left undB le Branch Block James F. Ginter Aurora Cardiovascular Services Patrick Loftis Marquette University, [email protected] Published version. Journal of the American Academy of Physician Assistants, Vol. 23, No. 12 (December 2010). Permalink. © 2010, American Academy of Physician Assistants and Haymarket Media Inc. Useded with permission. Abnormalities caused by left bundle branch block - Print Article - JAAPA http://www.jaapa.com/abnormalities-caused-by-left-bundle-branch-block/... << Return to Abnormalities caused by left bundle branch block James F. Ginter, MPAS, PA-C, Patrick Loftis, PA-C, MPAS, RN December 17 2010 One of the keys to achieving maximal cardiac output is simultaneous contraction of the atria followed by simultaneous contraction of the ventricles. The cardiac conduction system (Figure 1) coordinates the polarization and contraction of the heart chambers. As reviewed in the earlier segment of this department on right bundle branch block (RBBB), the process begins with a stimulus from the sinoatrial (SA) node. The stimulus is then slowed in the atrioventricular (AV) node, allowing complete contraction of the atria. From there, the stimulus proceeds to the His bundle and then to the left and right bundle branches. The bundle branches are responsible for delivering the stimulus to the Purkinje fibers of the left and right ventricles at the same speed, which allows simultaneous contraction of the ventricles. Bundle branch blocks are common disorders of the cardiac conduction system. They can affect the right bundle, the left bundle, or one of its branches (fascicular block), or they may occur in combination.
    [Show full text]
  • Location of the Human Sinus Node in Black Africans
    ogy: iol Cu ys r h re P n t & R y e s Anatomy & Physiology: Current m e o a t r a c n h A Research Meneas et al., Anat Physiol 2017, 7:5 ISSN: 2161-0940 DOI: 10.4172/2161-0940.1000279 Research article Open Access Location of the Human Sinus Node in Black Africans Meneas GC*, Yangni-Angate KH, Abro S and Adoubi KA Department of Cardiovascular and Thoracic Diseases, Bouake Teaching Hospital, Cote d’Ivoire, West-Africa *Corresponding author: Meneas GC, Department of Cardiovascular and Thoracic Diseases, Bouake Teaching Hospital, Cote d’Ivoire, West-Africa, Tel: +22507701532; E-mail: [email protected] Received Date: August 15, 2017; Accepted Date: August 22, 2017; Published Date: August 29, 2017 Copyright: © 2017 Meneas GC, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited. Abstract Objective: The purpose of this study was to describe, in 45 normal hearts of black Africans adults, the location of the sinoatrial node. Methods: After naked eye observation of the external epicardial area of the sinus node classically described as cavoatrial junction (CAJ), a histological study of the sinus node area was performed. Results: This study concluded that the sinus node is indistinguishable to the naked eye (97.77% of cases), but still identified histologically at the CAJ in the form of a cluster of nodal cells surrounded by abundant connective tissues. It is distinguished from the Myocardial Tissue.
    [Show full text]
  • Physiology of Heart Unit-4 (ZOOA-CC4-9-TH)
    Physiology of Heart Unit-4 (ZOOA-CC4-9-TH) Coronary Circulation: The heart muscle, like every other organ or tissue in your body, needs oxygen-rich blood to survive. Blood is supplied to the heart by its own vascular system, called coronary circulation. The aorta (the main blood supplier to the body) branches off into two main coronary blood vessels (also called arteries). These coronary arteries branch off into smaller arteries, which supply oxygen-rich blood to the entire heart muscle. The right coronary artery supplies blood mainly to the right side of the heart. The right side of the heart is smaller because it pumps blood only to the lungs. The left coronary artery, which branches into the left anterior descending artery and the circumflex artery, supplies blood to the left side of the heart. The left side of the heart is larger and more muscular because it pumps blood to the rest of the body. Coronary circulation is the circulation of blood in the blood vessels that supply the heart muscle (myocardium). Coronary arteries supply oxygenated blood to the heart muscle, and cardiac veins drain away the blood once it has been deoxygenated. Because the rest of the body, and most especially the brain, needs a steady supply of oxygenated blood that is free of all but the slightest interruptions, the heart is required to function continuously. Therefore its circulation is of major importance not only to its own tissues but to the entire body and even the level of consciousness of the brain from moment to moment.
    [Show full text]
  • 4B. the Heart (Cor) 1
    Henry Gray (1821–1865). Anatomy of the Human Body. 1918. 4b. The Heart (Cor) 1 The heart is a hollow muscular organ of a somewhat conical form; it lies between the lungs in the middle mediastinum and is enclosed in the pericardium (Fig. 490). It is placed obliquely in the chest behind the body of the sternum and adjoining parts of the rib cartilages, and projects farther into the left than into the right half of the thoracic cavity, so that about one-third of it is situated on the right and two-thirds on the left of the median plane. Size.—The heart, in the adult, measures about 12 cm. in length, 8 to 9 cm. in breadth at the 2 broadest part, and 6 cm. in thickness. Its weight, in the male, varies from 280 to 340 grams; in the female, from 230 to 280 grams. The heart continues to increase in weight and size up to an advanced period of life; this increase is more marked in men than in women. Component Parts.—As has already been stated (page 497), the heart is subdivided by 3 septa into right and left halves, and a constriction subdivides each half of the organ into two cavities, the upper cavity being called the atrium, the lower the ventricle. The heart therefore consists of four chambers, viz., right and left atria, and right and left ventricles. The division of the heart into four cavities is indicated on its surface by grooves. The atria 4 are separated from the ventricles by the coronary sulcus (auriculoventricular groove); this contains the trunks of the nutrient vessels of the heart, and is deficient in front, where it is crossed by the root of the pulmonary artery.
    [Show full text]
  • Blood Vessels
    BLOOD VESSELS Blood vessels are how blood travels through the body. Whole blood is a fluid made up of red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes), and plasma. It supplies the body with oxygen. SUPERIOR AORTA (AORTIC ARCH) VEINS & VENA CAVA ARTERIES There are two basic types of blood vessels: veins and arteries. Veins carry blood back to the heart and arteries carry blood from the heart out to the rest of the body. Factoid! The smallest blood vessel is five micrometers wide. To put into perspective how small that is, a strand of hair is 17 micrometers wide! 2 BASIC (ARTERY) BLOOD VESSEL TUNICA EXTERNA TUNICA MEDIA (ELASTIC MEMBRANE) STRUCTURE TUNICA MEDIA (SMOOTH MUSCLE) Blood vessels have walls composed of TUNICA INTIMA three layers. (SUBENDOTHELIAL LAYER) The tunica externa is the outermost layer, primarily composed of stretchy collagen fibers. It also contains nerves. The tunica media is the middle layer. It contains smooth muscle and elastic fiber. TUNICA INTIMA (ELASTIC The tunica intima is the innermost layer. MEMBRANE) It contains endothelial cells, which TUNICA INTIMA manage substances passing in and out (ENDOTHELIUM) of the bloodstream. 3 VEINS Blood carries CO2 and waste into venules (super tiny veins). The venules empty into larger veins and these eventually empty into the heart. The walls of veins are not as thick as those of arteries. Some veins have flaps of tissue called valves in order to prevent backflow. Factoid! Valves are found mainly in veins of the limbs where gravity and blood pressure VALVE combine to make venous return more 4 difficult.
    [Show full text]