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The Heart Surgical Society | Junior Anatomy Series Lecture 5 17 January 2023 Presented By Rebecca Irvine Learning Objectives 1 mins Structure of Chambers of the heart 10 mins the Session Main vessels of the heart and their role in 5 mins pulmonary or systemic circulation Branches of the aortic arch 2 mins Venous return from systemic circulation 2 mins Heart valves, chordae tendineae and 10 mins papillary muscles. KEY POINT Coronary arteries and veins 10 mins EXTRA MATERIAL Brief overview of conducting system of the 5 mins heart REVISION TIP Summary, Tips and Practice Questions 15 mins Surgical Society| Junior Anatomy SeriesLearning Objectives Heart & pericardium: Describe the anatomy of the heart, chambers, heart valves, the conducting system of heart; and the pericardium including its relevance in cardiac tamponade and pericarditis. Demonstrate surface markings of the heart, sites of auscultation of heart valves, and the site and palpation of apex beat. Coronary arteries: Describe the anatomy of coronary arteries and their involvement in ischaemic heart disease. Great vessels, arterial pulses and venous access: Describe the course of great arteries and great veins including their major branches. Demonstrate surface marking of the great vessels; common sites of venous access; and palpation of major arterial pulses around the body. Diagnostic Imaging of the Chest: Identify major thoracic structures on standard diagnostic images e.g. CT, MRI, X-ray and ultrasound. Surgical Society| Junior Anatomy SeriesChambers of the heart • 4 main chambers: • Right ventricle • Left ventricle • Right atrium • Left atrium • Also: • Fossa ovalis (and foramen ovale) • Right and left auricle Surgical Societynior Anatomy SeriesRight Atrium • Coronary sinus - returns blood from the heart into the RA • Right auricle - small appendage arising from each atrium • Fossa ovalis - remnant of the foramen ovale (allows blood to bypass the lungs in the fetus) • Musculi pectinate are ridges covering the wall of the right auricle • Crista terminalis is a smooth, muscular ridge at the roof of the atrium Surgical Societynior Anatomy SeriesRight Ventricle • The right ventricle receives deoxygenated blood from the right atrium, and pumps it through the pulmonary orifice (guarded by the pulmonary valve), into the pulmonary artery. • Forms the majority of the anterior border of the heart. • The interventricular septum separates the two ventricles Surgical Societynior Anatomy Series Left Atrium • Receives oxygenated blood from the four pulmonary veins. • Pumps it through the left atrioventricular orifice (guarded by the mitral valve) into the left ventricle. • Forms the posterior border (base) of the heart. • Left auricle Surgical Societynior Anatomy SeriesLeft Ventricle • Receives oxygenated blood from the left atrium, and pumps it through the aortic orifice (guarded by the aortic valve) into the aorta. • Forms the apex of the heart, as well as the left and diaphragmatic borders. Surgical Societynior Anatomy SeriesMain Vessels of the Heart • Pulmonary Artery • Transports blood to the lungs • Aorta • Transports blood to the body • Pulmonary Vein • Transports blood from the lungs • Vena Cava • Superior: Upper part of body • Inferior: Lower part of body Surgical Societyunior Anatomy SeriesAorta • Arises from the aortic orifice, with inflow via the aortic valve. • Ascending aorta, lies within the pericardium, rom it branch the coronary arteries. • Arch of the aorta, from which branch the major arteries to the head, neck and upper limbs. • Descending aorta which continues down through the diaphragm into the KEY POINT abdomen. The aorta pierces the diaphragm at T12. Surgical Societyior Anatomy SeriesBranches of the Aortic Arch • 3 major branches: • Brachiocephalic trunk: Splits into the right common carotid and right subclavian arteries. • Left common carotid artery • Left subclavian artery • The aortic arch ends at the T4. EXTRA MATERIAL Connected to the pulmonary trunk by the ligamentum arteriosum Surgical SocietyJunior Anatomy SeriesPulmonary Arteries • Receive deoxygenated blood and deliver it to the lungs. • Begin as the pulmonary trunk, separated from the right ventricle by the pulmonary valve. • At around the level of T5-T6, the pulmonary trunk splits into the right and left pulmonary arteries. Surgical Societyior Anatomy SeriesPulmonary Veins • Receive oxygenated blood from the lungs. • Four pulmonary veins, drain into the left atrium. • The oblique pericardial sinus can be found within the pericardium, between the left and right veins • The superior pulmonary veins return blood from the upper lobes of the lung, with the inferior veins returning blood from the lower lobes. Surgical Societynior Anatomy SeriesSuperior and Inferior Vena Cava • SVC receives deoxygenated blood from the upper body, into right atrium. • SVC formed by merging of the brachiocephalic veins. • IVC. receives deoxygenated blood from the lower body. • Formed in the pelvis by the common iliac veins joining together, and travels through the abdomen, collecting blood from the hepatic, lumbar, gonadal, renal and phrenic veins. KEY POINT The IVC pierces the diaphragm at T8. Surgical Societyior Anatomy SeriesHeart Valves • Atrioventricular valves: tricuspid and mitral • Semilunar valves: pulmonary and aortic • Atrioventricular valves: • Chordae tendinae • Papillary muscles – 3 support tricuspid, 2 support mitral REVISION TIP Tri = 3 Tricuspid has 3 papillary muscles Surgical Societyunior Anatomy SeriesT ricuspid Valve •Between the right atrium and the right ventricle •Three cusps: •Anterior •Septal •Posterior Surgical Societynior Anatomy Series Mitral Valve •Between the left atrium and the left ventricle •Two cusps: •Anterior •Posterior KEY POINT REVISION TIP The only valve to have TWO cusps, as MitraL Left hand side opposed to three Surgical Societyior Anatomy SeriesPulmonary Valve • Between right ventricle and the pulmonary trunk. • Three cusps: • Left • Right • Anterior • Sinus - wall of outflow vessel slightly dilated where sides of valve leaflet attaches • Lunule - free superior edge thickened • Nodule - free superior edge widest in midline Surgical Societyunior Anatomy SeriesAortic Valve • Between left ventricle and the ascending aorta • Three cusps: • Left • Right • Posterior • The L&R aortic sinuses mark the origin of the L&R coronary arteries Surgical Societynior Anatomy SeriesCoronary Arteries • Two main coronary arteries - left and right coronary arteries • Arise from the left and right aortic sinuses within the aorta. • Left coronary artery (LCA) branches into: • Left anterior descending (LAD) • Left marginal artery (LMA) • Left circumflex artery (LCx) • Right coronary artery (RCA) branches into: • Right marginal artery (RMA) • Posterior interventricular artery (PIv) posteriorly (in 80-85% of individuals) Surgical Societyunior Anatomy SeriesCardiac Veins • The cardiac veins drain into the coronary sinus • Empties into the right atrium • Main tributaries of the coronary sinus: • Great cardiac vein - largest tributary. • Small cardiac vein • Middle cardiac vein • Posterior cardiac vein Surgical Societynior Anatomy SeriesConducting System • Sequence of electrical events during one full contraction of the heart muscle: • Action potential is created by the sinoatrial (SA) node. • Spreads across the atria, causing them to contract. • Signed is delayed at the atrioventricular (AV) node. • Conducted into the bundle of His, down the interventricular septum. • Purkinje fibres spread the wave impulses along the ventricles, causing them to contract. Surgical Societyunior Anatomy Series Sinoatrial Node • Collection of pacemaker cells – generate electrical impulses. • Located in the upper wall of the right atrium, at the junction where the superior vena cava enters. • Wave of excitation spreads via gap junctions across both atria, resulting in atrial systole. • The rate at which the SA node generates impulses is influenced by the autonomic nervous system: Sympathetic nervous system – ↑ firing rate of the SA node, ↑ heart rate. Parasympathetic nervous system – ↓ firing rate of the SA node, ↓ heart rate. Surgical Societynior Anatomy SeriesAtrioventricular Node • Located within the atrioventricular septum, near the opening of the coronary sinus. • Delay the impulses by approximately 120ms - ensure atria have enough time to fully eject blood into the ventricles before ventricular systole. • The wave of excitation passes from the atrioventricular node into the atrioventricular bundle… Surgical Societynior Anatomy Series Bundle of His • AKA atrioventricular bundle • Continuation of the specialised tissue of the AV node • Transmits the electrical impulse from the AV node to the Purkinje fibres of the ventricles. • Descends down the interventricular septum, and divides into two main bundles: • Right bundle branch – conducts the impulse to the Purkinje fibres of the R ventricle • Left bundle branch – conducts the impulse to the Purkinje fibres of the L ventricle. Surgical Societynior Anatomy SeriesPurkinje Fibres • The Purkinje fibres are a network of specialised cells. • Abundent with glycogen and have extensive gap junctions. • Located in the subendocardial surface of the ventricular walls. • Rapid conduction allows coordinated ventricular contraction. Surgical Societynior Anatomy Series SBA Practice Questions PRACTICE QUESTION PRACTICE QUESTION PRACTICE QUESTION 1. At what vertebral level 3. What are the cusps of the 5. What does most of the does the aorta piece the pulmonary value? venous drainage of the heat diaphragm? • Superior, anterior, • T10 posterior • Middle cardiac vein • T4 • Left, right posterior • Great cardiac vein • T12 • Anterior, posterior, medial • Coronary sinus • T8 • Septal, anterior, posterior • Small cardiac vein • T6 • Left, right, anterior • Posterior cardiac vein 2. What is the name of the 4. Where do the main 6. What generates the embryological remanent that coronary arteries arise from? electrical impulses of the heat? connected the two atria? • Aortic sinuses • Sympathetic nervous • Marginal arteries system • Fossae ovalae • Atrioventricular node • Foramen ovalae • Posterior interventricular • Foramina ovali artery • Sinoatrial node • Fossa ovalis • Ascending aorta • Bundle of His • Parasympathetic nervous system Surgical Society| Junior Anatomy Series SBA Practice Questions PRACTICE QUESTION PRACTICE QUESTION PRACTICE QUESTION 1. At what vertebral level 3. What are the cusps of the 5. What does most of the does the aorta piece the tricuspid value? venous drainage of the heat diaphragm? • Superior, anterior, • T10 posterior • Middle cardiac vein • T4 • Left, right, posterior • Great cardiac vein •T12 • Anterior, posterior, medial •Coronary sinus • T8 • Septal, anterior, posterior • Small cardiac vein • T6 •Left, right, anterior • Posterior cardiac vein 2. What is the name of the 4. Where do the main 6. What generates the embryological remanent that coronary arteries arise from? electrical impulses of the heat? connected the two atria? • Aortic sinuses • Sympathetic nervous • Marginal arteries system • Fossae ovalae • Atrioventricular node • Foramen ovalae • Posterior interventricular •Sinoatrial node • Foramina ovali artery • Bundle of His •Fossa ovalis • Ascending aorta • Parasympathetic nervous system Surgical Society| Junior Anatomy SeriesQ1 Surgical Society | Junior Anatomy SeriesAnswer Brachiocephalic trunk Surgical Societynatomy SeriesQ2 Surgical Society | Junior Anatomy SeriesAnswer Ascending aorta Surgical Societynatomy SeriesQ3 Surgical Society | Junior Anatomy Series Answer Atrioventricular node Surgical Societynatomy SeriesQ4 Surgical Society | Junior Anatomy Series Answer Aortic valve Surgical Societynatomy SeriesQ5 Surgical Society | Junior Anatomy SeriesAnswer Right coronary artery Surgical Societynatomy SeriesQ6 Surgical Society | Junior Anatomy SeriesAnswer Anterior interventricul ar branch (of the LCA) Surgical SocietyAnatomy SeriesQ7 Surgical Society | Junior Anatomy SeriesAnswer Left pulmonary veins Surgical Societynatomy SeriesQ8 Surgical Society | Junior Anatomy SeriesAnswer Right auricle Surgical Societynatomy SeriesQ9 Bonus! Surgical Societynior Anatomy SeriesAnswer Descending aorta Bonus: oesophagus Surgical Societyr Anatomy SeriesQ10 Surgical Society | Junior Anatomy SeriesAnswer Pulmonary trunk Surgical Societyatomy SeriesSurgical Society | Junior Anatomy Series Rebecca Irvine JAS LEADS Contact Phase 1a: Anya Nanchahal (sn1119) ri20@ic.ac.uk Phase 1b: Andrea Perez Navarro (ap6618) CPA Lead: Defne Artun (da1019) Feedback Please fill out the following feedback form in order to receive a copy of the slides on MedAll, along with bonus VSAQs to aid your Form revision! our next lecture on the Mediastinum.e you on Tuesday 24th January 2022 for http://bit.ly/3iwPrXE