Sudden Death in Racehorses: Postmortem Examination Protocol
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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. -
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Folia Morphol. Vol. 78, No. 2, pp. 283–289 DOI: 10.5603/FM.a2018.0077 O R I G I N A L A R T I C L E Copyright © 2019 Via Medica ISSN 0015–5659 journals.viamedica.pl Observations of foetal heart veins draining directly into the left and right atria J.H. Kim1, O.H. Chai1, C.H. Song1, Z.W. Jin2, G. Murakami3, H. Abe4 1Department of Anatomy and Institute of Medical Sciences, Chonbuk National University Medical School, Jeonju, Korea 2Department of Anatomy, Wuxi Medical School, Jiangnan University, Wuxi, China 3Division of Internal Medicine, Jikou-kai Clinic of Home Visits, Sapporo, Japan 4Department of Anatomy, Akita University School of Medicine, Akita, Japan [Received: 19 June 2018; Accepted: 8 August 2018] Evaluation of semiserial sections of 14 normal hearts from human foetuses of gestational age 25–33 weeks showed that all of these hearts contained thin veins draining directly into the atria (maximum, 10 veins per heart). Of the 75 veins in these 14 hearts, 55 emptied into the right atrium and 20 into the left atrium. These veins were not accompanied by nerves, in contrast to tributaries of the great cardiac vein, and were negative for both smooth muscle actin (SMA) and CD34. However, the epithelium and venous wall of the anterior cardiac vein, the thickest of the direct draining veins, were strongly positive for SMA and CD34, respectively. In general, developing fibres in the vascular wall were positive for CD34, while the endothelium of the arteries and veins was strongly positive for the present DAKO antibody of SMA. -
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. -
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. -
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. -
Ultrastructure of the Normal Atrial Endocardium R
Brit. Heart J., 1966, 28, 785. Ultrastructure of the Normal Atrial Endocardium R. A. LANNIGAN AND SALEH A. ZAKI From the Department of Pathology, University of Birmingham, and the Department of Pathology, University of Assiut, U.A.R. Surgical biopsies of the heart and early needle Thin sections were then cut and examined on an A.E.I. "biopsies" at necropsy now permit ultrastructural E M 6 electron microscope. investigations into many cardiac conditions. There For light microscopy, blocks of the whole circum- are, however, very few such studies on normal human ference were embedded in paraffin and sections were stained with Ehrlich's hTmatoxylin and eosin, van myocardium and none are available on human or Gieson's stain, Lawson's modification of the Weigert- animal endocardium. The commonest surgical Sheridan elastic stain, the periodic-acid Schiff reaction, specimens from the heart are from the left or right and Hale's dialysed iron. atrial appendages, and this material has been used to study normal structure, as a baseline for the investigation of cardiac diseases such as rheumatic RESULTS heart disease and fibro-elastosis, etc. For obvious Light Microscopy reasons, it is difficult to obtain fresh material from "normal" hearts, and specimens were selected for The structure of the left atrial wall has been electron microscopy which were within normal described by Koniger (1903), Nagayo (1909), Von limits on the light microscope (Lannigan, 1959). Glahn (1926), and Gross (1935), and the structure of the atrial appendages, which was shown to be similar to that of the atrium, was described by MATERIAL AND METHODS Waaler (1952), Lannigan (1959), and Ling, Wang, Three left atrial appendages and three right append- and Kuo (1959). -
Abnormally Enlarged Singular Thebesian Vein in Right Atrium
Open Access Case Report DOI: 10.7759/cureus.16300 Abnormally Enlarged Singular Thebesian Vein in Right Atrium Dilip Kumar 1 , Amit Malviya 2 , Bishwajeet Saikia 3 , Bhupen Barman 4 , Anunay Gupta 5 1. Cardiology, Medica Institute of Cardiac Sciences, Kolkata, IND 2. Cardiology, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Shillong, IND 3. Anatomy, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Shillong, IND 4. Internal Medicine, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Shillong, IND 5. Cardiology, Vardhman Mahavir Medical College (VMMC) and Safdarjung Hospital, New Delhi, IND Corresponding author: Amit Malviya, [email protected] Abstract Thebesian veins in the heart are subendocardial venoluminal channels and are usually less than 0.5 mm in diameter. The system of TV either opens a venous (venoluminal) or an arterial (arterioluminal) channel directly into the lumen of the cardiac chambers or via some intervening spaces (venosinusoidal/ arteriosinusoidal) termed as sinusoids. Enlarged thebesian veins are reported in patients with congenital heart disease and usually, multiple veins are enlarged. Very few reports of such abnormal enlargement are there in the absence of congenital heart disease, but in all such cases, they are multiple and in association with coronary artery microfistule. We report a very rare case of a singular thebesian vein in the right atrium, which was abnormally enlarged. It is important to recognize because it can be confused with other cardiac structures like coronary sinus during diagnostic or therapeutic catheterization and can lead to cardiac injury and complications if it is attempted to cannulate it or pass the guidewires. -
Electrocardiography: a Technologist's Guide to Interpretation
CONTINUING EDUCATION Electrocardiography: A Technologist’s Guide to Interpretation Colin Tso, MBBS, PhD, FRACP, FCSANZ1,2, Geoffrey M. Currie, BPharm, MMedRadSc(NucMed), MAppMngt(Hlth), MBA, PhD, CNMT1,3, David Gilmore, ABD, CNMT, RT(R)(N)3,4, and Hosen Kiat, MBBS, FRACP, FACP, FACC, FCCP, FCSANZ, FASNC, DDU1,2,3,5 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia; 2Cardiac Health Institute, Sydney, New South Wales, Australia; 3Faculty of Science, Charles Sturt University, Wagga Wagga, New South Wales, Australia; 4Faculty of Medical Imaging, Regis College, Boston, Massachusetts; and 5Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia CE credit: For CE credit, you can access the test for this article, as well as additional JNMT CE tests, online at https://www.snmmilearningcenter.org. Complete the test online no later than December 2018. Your online test will be scored immediately. You may make 3 attempts to pass the test and must answer 80% of the questions correctly to receive 1.0 CEH (Continuing Education Hour) credit. SNMMI members will have their CEH credit added to their VOICE transcript automatically; nonmembers will be able to print out a CE certificate upon successfully completing the test. The online test is free to SNMMI members; nonmembers must pay $15.00 by credit card when logging onto the website to take the test. foundation for understanding the science of electrocardiog- The nuclear medicine technologist works with electrocardio- raphy and its interpretation. graphy when performing cardiac stress testing and gated cardiac imaging and when monitoring critical patients. -
Basic ECG Interpretation
12/2/2016 Basic Cardiac Anatomy Blood Flow Through the Heart 1. Blood enters right atrium via inferior & superior vena cava 2. Right atrium contracts, sending blood through the tricuspid valve and into the right ventricle 3. Right ventricle contracts, sending blood through the pulmonic valve and to the lungs via the pulmonary artery 4. Re-oxygenated blood is returned to the left atrium via the right and left pulmonary veins 5. Left atrium contracts, sending blood through the mitral valve and into the left ventricle 6. Left ventricle contracts, sending blood through the aortic Septum valve and to the body via the aorta 1 http://commons.wikimedia.org/wiki/File:Diagram_of_the_human_heart 2 _(cropped).svg Fun Fact….. Layers of the Heart Pulmonary Artery – The ONLY artery in the body that carries de-oxygenated blood Pulmonary Vein – The ONLY vein in the body that carries oxygenated blood 3 4 Layers of the Heart Endocardium Lines inner cavities of the heart & covers heart valves (Supplies left ventricle) Continuous with the inner lining of blood vessels Purkinje fibers located here; (electrical conduction system) Myocardium Muscular layer – the pump or workhorse of the heart “Time is Muscle” Epicardium Protective outer layer of heart (Supplies SA node Pericardium in most people) Fluid filled sac surrounding heart 5 6 http://stanfordhospital.org/images/greystone/heartCenter/images/ei_0028.gif 1 12/2/2016 What Makes the Heart Pump? Electrical impulses originating in the right atrium stimulate cardiac muscle contraction Your heart's -
Structures of the Heart
Anatomy Tip Structures of the Heart In an effort to aid Health Information Management Coding Professionals for ICD-10, the following anatomy tip is provided with an educational intent. TIP: The Heart is made up of three main structures: 1. The Pericardium 2. The Heart Wall 3. The Chambers of the Heart The pericardium surrounds the heart. The outer layer, called the fibrous pericardium, secures the heart to surrounding structures like the blood vessels and the diaphragm. The inner layer, called the serous pericardium, is a double-layered section of the heart. Inside the two layers, serous fluid, known as pericardial fluid, lubricates and helps the heart move fluidly when beating. The heart wall is made up of three tissue layers: the epicardium, the myocardium, and the endocardium. The epicardium, which is the outermost layer, is also known as the visceral pericardium because it is also the inner wall of the pericardium. The middle layer, known as the myocardium, is formed out of contracting muscle. The endocardium, the innermost layer, covers heart valves and acts as a lining of the heart chambers. It is also in contact with the blood that is pumped through the heart, in order to push blood into the lungs and throughout the rest of the body. The four heart chambers are crucial to the heart’s function, composed of the atria, the right atrium and left atrium, and ventricles, the right ventricle and left ventricle. The right and left atria are thin-walled chambers responsible for receiving blood from veins, while the left and right ventricle are thick-walled chambers responsible for pumping blood out of the heart. -
Functions of the Heart • Generaqon of Blood Pressure • Rouqng of Blood
Functions of the Heart • Generaon of blood pressure • Rou'ng of blood • Ensuring unidirecon flow of blood • Regula'on of blood supply 1 2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduc'on or display. CO2 O2 Pulmonary circuit O2-poor, CO2-rich O2-rich, blood CO2-poor blood Systemic circuit CO2 O2 3 4 5 6 7 8 9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduc'on or display. Le AV (bicuspid) valve Right AV (tricuspid) valve Fibrous skeleton Openings to coronary arteries AorCc valve Pulmonary valve (a) 10 11 12 13 14 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduc'on or display. 10 1 Blood enters right atrium from superior and inferior venae cavae. 2 Blood in right atrium flows through right Aorta Le pulmonary AV valve into right ventricle. 11 artery 3 Contracon of right ventricle forces 5 5 pulmonary valve open. 4 Blood flows through pulmonary valve 9 Pulmonary trunk Superior into pulmonary trunk. vena cava 4 Le pulmonary 6 5 Blood is distributed by right and le veins pulmonary arteries to the lungs, where it Right 6 unloads CO and loads O . pulmonary 2 2 Le atrium veins 1 AorCc valve 6 Blood returns from lungs via pulmonary veins to leE atrium. 3 7 Le AV 7 Blood in le atrium flows through le AV Right (bicuspid) valve 8 valve into leE ventricle. atrium Le ventricle 2 8 Contracon of leE ventricle (simultaneous with Right AV step 3 ) forces aorCc valve open. (tricuspid) valve 9 Blood flows through aorCc valve into Right ascending aorta. -
Development of the Endocardium
Pediatr Cardiol DOI 10.1007/s00246-010-9642-8 RILEY SYMPOSIUM Development of the Endocardium Ian S. Harris • Brian L. Black Received: 7 January 2010 / Accepted: 17 January 2010 Ó The Author(s) 2010. This article is published with open access at Springerlink.com Abstract The endocardium, the endothelial lining of the cardiac crescent. We propose a third model that reconciles heart, plays complex and critical roles in heart develop- these two views and suggest future experiments that might ment, particularly in the formation of the cardiac valves resolve this question. and septa, the division of the truncus arteriosus into the aortic and pulmonary trunks, the development of Purkinje Keywords Endocardium Á Endothelial Á Heart fibers that form the cardiac conduction system, and the formation of trabecular myocardium. Current data suggest that the endocardium is a regionally specialized endothe- Overview of Cardiogenesis lium that arises through a process of de novo vasculogen- esis from a distinct population of mesodermal cardiogenic The cardiovascular system is the first organ system to form precursors in the cardiac crescent. In this article, we review and function in the vertebrate embryo. The heart forms recent developments in the understanding of the embryonic when regions of bilaterally symmetrical cardiac progenitor origins of the endocardium. Specifically, we summarize cells in the anterior lateral mesoderm fuse at the ventral vasculogenesis and specification of endothelial cells from midline to form a linear tube, which is continuous with the mesodermal precursors, and we review the transcriptional dorsal aorta anteriorly and the cardinal veins posteriorly pathways involved in these processes. We discuss the [5].