Heart and Its Components (ANAT)LEC_203 PDF
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Uploaded by VeritableJadeite
University of Northern Philippines
2021
Dr. Leslie Asuncion-Viado
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This document is a lecture on heart anatomy, covering introduction to heart components, function, and location. It includes details on the sternum, pericardial sinuses, nerve supply, functional circuits, surfaces, borders, structures, and the fibrous skeleton of the heart.
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(003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION)...
(003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 STERNAL ANGLE (ANGLE OF LOUIS) OUTLINE - Articulation of the manubrium with the body of I. STERNUM the sternum II. PERICARDIUM - Presence of a transverse ridge on the anterior aspect of the sternum which lies at the 2nd level III. PERICARDIAL SINUSES of the costal cartilage IV. NERVE SUPPLY OF PERICARDIUM - Lies opposite the intervertebral disc between V. COMPONENTS OF BECK’S TRIAD IN T4 and T5 vertebrae. CARDIAC TAMPONADE XIPHISTERNAL JOINT - Opposite the body of the T9 vertebrae. VI. HEART (INTRODUCTION) VII. FUNCTIONAL CIRCUITS OF THE HEART A. PARTS OF THE STERNUM VIII. ORIENTATION OF THE HEART IX. SURFACES OF THE HEART 1. MANUBRIUM X. BORDERS OF THE HEART - Upper part of the sternum - Articulates with the body of the sternum at the XI. STRUCTURES OF THE HEART manubriosternal joint XII. FIBROUS SKELETON OF THE HEART - Articulates with the clavicles and with the 1st XIII. TEST YOUR KNOWLEDGE costal cartilage and the upper part of the 2nd I. STERNUM costal cartilages on each side - Lies in the midline of the anterior chest wall - Lies opposite the 3 and 4 thoracic vertebrae - It is a flat bone divided in to 3 parts: 2. BODY OF STERNUM a. Manubrium - Articulates above with the manubrium at the b. Body of the sternum manubriosternal joint and below with the xiphoid c. Xiphoid process process at the xiphisternal joint on each side - Articulates with the 2 to 7 costal cartilages 3. XIPHOID PROCESS - Thin plate of cartilage that becomes ossified at its proximal end during adult life - No ribs or costal cartilages are attached to it II. PERICARDIUM Figure 1. The sternum. Connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Figure 2. The pericardium. Also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. Page 1 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 Pericardium - Fibrous sac - Encloses the heart and the roots of the great vessels - Double layer sac - Functions: - Restrict excessive movements of the heart as a whole (does not allow the heart to go swinging inside the mediastinum) - Serve as a lubricated container in which the different parts of the heart can contract (prevents creation of friction between the heart and the mediastinal organs when the heart contracts Figure 3. Parts of the pericardium. Location of the heart - Within the middle mediastinum ** Pericardial Cavity - Posterior to the body of the sternum and the 2nd to Slit-like space between the parietal and visceral the 6th costal cartilages layers - Anterior to the T5 – T8 vertebrae Pericardial fluid = 50 mL - Acts as a lubricant to facilitate movements of A. PARTS OF THE PERICARDIUM the heart without friction or rubbing 1. Fibrous Pericardium - Outermost part / superficial layer - Strong fibrous part of the sac (consists of dense, loose connective tissue) - Firmly attached below the central tendon of the diaphragm - Fuses with the outer coats of the great blood vessels passing through it (aorta, pulmonary trunk, superior and inferior vena cava, pulmonary trunk) - Attached in front to the sternum by the sternopericardial ligaments - Protects the heart from overfilling because it is fibrous and unyielding 2. Serous Pericardium Figure 4. The Pericardial Cavity. - Innermost part - Lines the fibrous pericardium III. PERICARDIAL SINUSES - Coats the heart - 2 Layers: - Spaces posterior to the heart Parietal layer - Heart is being lifted from the central tendon - Lines the fibrous pericardium - Pericardial sinuses form as a consequence of - Reflected around the roots of the great vessels to the way the heart bends during development become continuous with the visceral layer - Extensions of the pericardial cavity and not - Holds the heart in place in the chest cavity and separate compartmental spaces protects from infections Visceral layer - Closely attached to the heart - Often called epicardium Page 2 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 IV. NERVE SUPPLY OF PERICARDIUM Figure 5. Pericardial sinuses. Figure 7. Nerve supply of pericardium. Types of Sinuses: Phrenic Nerve 1. Oblique Sinus - A mixed motor/sensory nerve which originates from - Found in the posterior surface of the heart the C3-C5 spinal nerves in the neck - Bounded laterally by the entrance of the pulmonary - Important for breathing because it provides veins and inferiorly by the orifice of the inferior vena exclusive motor control of the diaphragm, the cava primary muscle of respiration - Reflection around the large veins (inferior and superior - Supplies: vena cava) a. Fibrous pericardium b. Parietal layer of serous pericardium - Forms an inverted U-shaped Cul-de- sac - Runs along the long axis of the heart from the apex to the ascending aorta Vagus Nerve & Sympathetic Branches - Space behind the heart - the tenth cranial nerve or CN X, and interfaces with 2. Transverse Sinus the parasympathetic control of the heart, lungs, and digestive tract - Short horizontal space (superiorly) - Supplies: - Lies between the reflection of the serous pericardium o Visceral layer of serous pericardium around the aorta and pulmonary trunk and the reflection around the large veins - Posterior to the ascending aorta and pulmonary V. BECK’S TRIAD trunk and anterior to the superior vena cava - Collection of three clinical signs associated with pericardial tamponade which is due to an excessive accumulation of fluid within the pericardial sac. Figure 6. Locations of the pericardial sinuses. Page 3 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 1. Jugular vein distention (JVD) - Due to the pressure **Atrioventricular groove separates the atria from the exerted on the right ventricle, diastolic filling decreases. This ventricles *AV grooves contains the coronary arteries: causes blood to back up into the right atria and the veins that 1. Right AV groove will contain right coronary artery. return blood to the heart, most notably the jugular veins. In a 2. Left AV groove will contain left anterior descending. patient with cardiac tamponade, jugular vein distension will **Interventricular groove separates the right and left ventricle. be present even when they are sitting upright. 2. Muffled heart sounds - occurs because of the insulating VII. FUNCTIONAL CIRCUITS OF THE effect of the fluid in the pericardial sac. When sound travels HEART through fluid, it sounds distant or suppressed because it is traveling through a thicker median. 3. Hypotension - occurs because the heart is hindered in its ability to pump blood. When the heart cannot work efficiently, the rest of the body does not get supplied with the necessary amount of blood. This can result in the body going into shock and even cardiac arrest. **When the pericardial fluid in the pericardial sac is increased more than 100 ml, it creates a cardiac tamponade. *Cardiac tamponade, also known as pericardial tamponade, is when fluid in the pericardium (the sac around the heart) builds up, resulting in compression of the heart. VI. HEART (INTRODUCTION) - Hollow muscular organ - Pyramid shaped - Lies within the pericardium in middle of the mediastinum - Connected at its base to the great blood vessels - Lies freely within the pericardium - Coronary arteries are embedded beneath the fats in the AV and IV grooves **Making a fist is the size of a normal heart **Heart is not really in the middle. 1/3 is on the right side. 2/3 is on the left side. Tilted to the left. Figure 9. Pulmonary and Systemic pathways. a. Pulmonary Circuit Right side of the heart Blood travels short distance to the lungs Against low peripheral resistance (lungs) Transport blood between the heart and the lungs b. Systemic Circuit Left side of the heart Blood travels a long distance through the body Against high peripheral resistance (arteries of peripheral vascular system) Closed circuit between the heart and the rest of the body Figure 8. Grooves of the Heart. Page 4 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 VIII. ORIENTATION OF THE HEART 2. Diaphragmatic surface (inferior surface) - Formed mainly by the right and left ventricles, - Aligned obliquely within the thorax which are separated by the posterior interventricular groove - Two-thirds of the heart lies to the left of the - Formed also by the inferior surface of the right midline and one-third to the right of the midline atrium where inferior vena cava opens 3. Base of the Heart (posterior surface) - Apex (pointed end) - Formed mainly by the left atrium with the openings o directed downward, forward, and to the of the pulmonary veins and, to a lesser extent, by left the right atrium - Lies opposite the apex o formed from left ventricle (inferolateral - Called base due to its pyramid shape part of the LV) 4. Apex of the Heart o lies at the level of the fifth left - Tip of the heart intercostal space, left mid clavicular - Formed by the left ventricle line - Directed downwards, forward, to the left o 3.5 inches (9 cm) from the midline - Lies at 5th intercostal space left mid-clavicular line o Apex beat can be seen and palpated - 3.5 inches (9 cm) from the midline - Apex beat can usually be seen and palpated in the living patient X. BORDERS OF THE HEART Figure 10. Anatomical position of the heart. IX. SURFACES OF THE HEART 1. Sternocostal surface (anterior surface) Figure 11. Borders and Surfaces of the Heart. - Formed mainly by the right atrium and the right ventricle which are separated by vertical Right border atrioventricular groove/sulcus - Formed by the right atrium - Right ventricle is separated from the left ventricle Left border by the anterior interventricular groove - Formed by the left atrium/auricle ABOVE & inferior portion of left ventricle Lower border - Formed by right ventricle but also by right atrium Apex - Formed by left ventricle, the tip of the heart NOTE: Border is important to recognize when examining the posteroanterior and lateral view of radiograph of the heart. Also, to determine which “bump” is abnormal in size Page 5 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 2. Epicardium 1. Covered externally with serous pericardium 2. the outermost covering of the heart or part of the heart which is also known as the visceral layer of the serous pericardium 3. Endocardium 1. Lined internally with a layer of endothelium 2. found in the inner most part which line the endothelium ** The atrial portion of the heart has relatively thin walls, whereas the ventricular portion of the heart has thick walls. Left image: Normal Radiograph/ Chest X-ray Right border – RA Inferior border – RV Left border - 1st bump – aorta - 2nd bump – pulmonary artery - 3rd bump – left atrium - 4th bump – left ventricle ** 1st bump is enlarged – aneurysm ** 2nd bump is very bulging – pulmonary arterial hypertension ** 3rd bump big – left arterial enlargement (but left atrium is found in the posterior side of the heart) Figure 11. The walls of the heart. The heart has three distinct layers NOTE: Very important to ask for a lateral view because namely Epicardium, Myocardium, and Endocardium the spaces between are seen. ** If left atrium is enlarged, the space between the heart B. CARDIAC INTERNAL SEPTUM and thoracic vertebrae will be obscured. 2 parts: ** If the space between the sternum and the heart is obscured, the right ventricle is enlarged. 1. Interatrial Septum a) Separating left and right atria. XI. STRUCTURES OF THE HEART b) Runs from the anterior wall of the heart backward and to the right A. WALLS OF THE HEART 2. Interventricular Septum 1. Myocardium a) Separates the right and left a) Cardiac muscle ventricles b) The myocardium consists of cardiac muscles in a b) Lies obliquely spiral arrangement of myocardium that squeeze blood c) The right surface facing forward through the heart in the proper directions (inferiorly and to the right and the left surface through the atria and superiorly through the facing backward and to the left ventricles). Unlike all other types of muscle cells, d) Lower, thicker muscular part in the cardiac muscle cells: smaller upper, thinner a) Branch, membranous part b) Join at complex junctions called intercalated discs so that they form cellular networks, **has two parts, the membranous part which is found c) Each contains single, centrally located nuclei. A cardiac muscle cell is not called a fiber. The above and the muscular part below term cardiac muscle fiber, when used, refers. to a long row of joined cardiac muscle cells. Page 6 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 **This is important because in this area, congenital C. RIGHT ATRIUM anomalies will be present. One has to tell if there is a hole in the septum, whether if it is the membranous (above) or 2 parts: the muscular type of ventricular septum. The most a) Main cavity common would be that membranous type. b) Auricle (a small outpouching) **The muscular part of the interventricular septum will Sulcus terminalis indicate where the conducting system device is, thus, - Vertical groove outside the heart this part of the heart is very important. - Junction between the right atrium and the right auricle - A groove on the external side of the heart, resulting from lining of crista terminalis on the internal. This is a useful landmark in approximating the location of the sinoatrial node (pacemaker of the conduction system). **Anterior and posterior interventricular grooves on the surface of the heart mark the position of the ventricular Crista terminalis septum. - Ridge inside the heart - Boundary between atrium proper and the right **Looking at the heart grossly, one can note of the fat that is auricle in vertical line anteriorly. This is the anterior interventricular groove where the left anterior descending artery is. This marks the position of the ventricular septum. Figure 14. The Crista Terminalis. (crista = "crest" + "terminal"), representing the end of the smooth wall and the beginning of the pectinate wall of the heart. Page 7 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 I. Main Cavity - Posterior to Crista terminals - Embryologically from sinus venosus - Smooth-walled - In the right atrial cavity, the fossa ovalis is usually seen but it is closed. II. Right Auricle - Roughened or trabeculated by bundles of a muscle fiber called musculi pectinate, the ridges or roughened surfaces of right auricle. - Embryologically from primitive atrium Figure 15. Inferior and Superior Vena Cava. The heart receives deoxygenated blood from the body through the Superior Vena Cava (Upper arrow) and Lower Vena Cava (Lower arrow). 3. Coronary Sinus - Drains most of the blood from the heart wall - Between the inferior vena cava and the atrioventricular orifice - It is guarded by a rudimentary, nonfunctioning valve (THEBESIAN VALVAE) - The coronary sinus is located on the posterior (inferior) side of the heart and receives almost all of the deoxygenated blood from the vasculature of the heart. The coronary sinus opens into the right atrium anteriorly and inferiorly to the orifice of the inferior vena cava. 4. Right Atrioventricular Orifice 4 openings of the Right Atrium - Anterior to in inferior vena cava 1. Superior Vena Cava - Guarded by TRICUSPID VALVE - Opens into the upper part - Tricuspid valve guards the right atrium from the - No valve right ventricle - Returns the blood to the heart from the upper half of the body 2. Inferior Vena Cava - Opens into the lower part - Guarded by a rudimentary, nonfunctioning valve Eustachian valve o This valve is very important when it becomes prominent because it may cause obstruction to blood flow and thrombosis. - Returns the blood to the heart from the lower half of the body Figure 16. Coronary sinus and Right AV Orifice. The Coronary sinus (yellow arrow) is the large vessel that collects blood from the myocardium while the right AV Orifice (blue aperture) serves as communication between right atrium and ventricle. Page 8 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 D. RIGHT VENTRICLE Tricuspid Valves - Guards AV orifices - Connects the RA and pulmonary trunk - With cusps from folds of endocardium - Infundibulum - Composed of anterior, septal, and inferior o funnel-shaped narrowing cusps o approaches the pulmonary orifice - Bases attached to fibrous skeleton o constitutes the Right Ventricular - Free edges and ventricular surfaces attached Outflow Tract (RVOT) to chordae tendinae - Thicker than RA, crescent-shaped, and shows o Chordae tendinae prevents prolapse several internal projecting ridges formed of **When there is myocardial infraction, there is poor muscle bundles. supply of blood into the heart’s muscles. Therefore, - Communicates with the right atrium through the the chordae may be detached or not fully functioning atrioventricular orifice and with the pulmonary well so there will be prolapse of the tricuspid leaflet trunk through the pulmonary orifice causing tricuspid regurgitation. It is very important that the chordae tendinae and the papillary muscles **It is important to remember that the infundibulum may are very good or functioning well to prevent prolapse be stenosed, or not formed. So, it may cause right of the tricuspid valves. ventricular outflow tract (RVOT) obstruction. It may be found in congenital heart diseases like Tetralogy of Fallot. Pulmonic Valve Leaflets Trabeculae Carneae - Guards pulmonary orifices - Sponge-like structure - 3 cusps from folds of endocardium: o Anterior, right, and left cusps. - Internal projecting ridges formed of muscle o The bases of the cusps are bundles attached to the fibrous ring of the 3 Types: skeleton of the heart, whereas 1. Papillary Muscles their free edges and ventricular - Project inward surfaces are attached to the - Bases to the ventricular wall chordae tendineae. - Apices to chordae tendinae to the - Pulmonary Sinus cusps of the Tricuspid valve o Curved lower margins and 2. Moderator Band (Septomarginal Trabecula) sides of each cusp attached to - From the septal to the anterior arterial wall ventricular wall o Forming a cup-like cavity - Transports the right branch of the - Cusps open towards the pulmonic trunk atrioventricular bundle - No chordae tendinae nor papillary - Resists over distension of the muscles attached ventricular wall - Systole: cusps pressed against 3. Ridges pulmonary artery - Diastole: blood fill cusps, closing them Page 9 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 **During ventricular systole, the cusps of the valve are pressed against the wall of the pulmonary trunk by the outrushing blood. **During diastole, blood flows back toward the heart and enters the sinuses; the valve cusps fill, come into apposition in the center of the lumen, and close the pulmonary orifice. E. LEFT ATRIUM - Main cavity and auricle - Located posterior to RA and forms the greater part of the base or the posterior surface of the heart - Forms mostly the base of the heart - Behind lie the oblique sinus and the serous pericardium, the fibrous pericardium separates it from the esophagus - Fossa ovalis not prominent - Auricle has ridges (PECTINATE MUSCLE) - No crista terminalis - 4 pulmonary veins (no valves) open to LA - Blood flow goes into the left ventricle and is guarded by mitral valve. - The interior of the left atrium is smooth, but the left auricle XII. FIBROUS CARDIAC SKELETON possesses muscular ridges as in the right auricle. The fibrous cardiac skeleton is a dense connective *the right atrium is more anterior than the left tissue that forms the heart wall aside from the cardiac F. LEFT VENTRICLE muscle tissue - Blood from LA goes to LV, the aorta (communicate with Fibrous cardiac skeleton is consist of 4 dense connective LA and Aorta) tissue rings that surrounds the atrioventricular, - Aortic vestibule – below the aortic orifice (LVOT) pulmonary and aortic valve orifices and are continuous - Cross section – circular with the lower part of atrial septum and the upper - 3x thicker than RV membranous part of ventricular septum - 6x higher BP than RV 1. Pulmonary fibrous ring - Well-developed trabeculae carnae 2. Aortic fibrous ring o With 2 papillary muscles 3. Right atrioventricular fibrous ring Mitral Valve 4. Left atrioventricular fibrous ring - Guards atrioventricular orifice - 2 cusps (anterior and posterior) - Anterior MV is larger than posterior MV Aortic Valve - Guards aortic orifice - Right; left and posterior - Contains sinuses - Coronary arteries - One cusp is situated on the anterior wall (right cusp) and two are located on the posterior wall (left and posterior cusps). - Behind each cusp, the aortic wall bulges to form an aortic sinus. **The name of the aortic valve is based on the coronary artery that is being given off. **The posterior valve is also known as the non- coronary aortic cusp. **The left coronary cusp will give off the left main coronary artery, which divides into circumflex and left anterior descending artery. **The right aortic cusp will give off the right coronary artery. Page 10 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 Functions: TEST YOUR KNOWLEDGE - Separate the muscular walls of the atria from those of ventricles but provide attachment for the “Relax and take a deep breath. Now it’s muscle fibers time to test what we’ve learned!” - Support & attachment for the bases of valve cusps 1. A fibrous sac which encloses the heart and the roots of o Prevent the valves from stretching and the great vessels. becoming incompetent a. endocardium b. pericardium o Keep valve orifices patent c. myocardium - Electrical insulation between atria and ventricles d. perineurium o Electrical discontinuity from atria & 2. Functions of the above structure. Select all that apply. ventricles a. restrict excessive movements of the heart as a whole b. serve as a lubricated container in which the different parts of the heart can contract c. allows extensive expansion of the heart during contraction d. prevents creation of friction e. does not allow the heart to go swinging 3. It is the outermost part, consists of dense, loose connective tissue and a strong fibrous part of the sac. 4. It is the outermost part, consists of dense, loose connective tissue and a strong fibrous part of the sac. 5. It is the innermost part of the sac that coats the heart. 6. The two layers of the serous pericardium. a. endocardium & pericardium b. endoneurium & perineurium c. parietal & visceral d. oblique & transverse Figure 17. Fibrous cardiac skeleton. - Anchors the valves of the heart, and gives attachment to the myocardium, 7. Normally, how much volume of fluid is there in the above and below. pericardial cavity? a. 30 mL b. 75 mL c. 45 mL d. 50 mL 8. Identify the structure. BLUE RECTANGLE 9. Identify the structure. GREEN RECTANGLE Page 11 of 13 CMED 1A (003) HEART AND ITS COMPONENTS (INTRODUCTION, FUNCTION, AND LOCATION) DR. LESLIE ASUNCION-VIADO | 01/04/21 10. The phrenic nerve supplies this/these structure/s. 17. True or False. The pulmonary circuit is against a. visceral layer high peripheral resistance. b. parietal layer & visceral layer 18. True or False. The systemic circuit is against c. parietal layer & fibrous pericardium high peripheral resistance. d. visceral layer & fibrous pericardium 19. The apex of the heart lies at the? 11. The vagus nerve & sympathetic branches supplies a. 5th intercostal space, left midclavicular line this/these structure/s. b. 6th intercostal space, left midclavicular line a. visceral layer c. 4th intercostal space, left midclavicular line b. parietal layer & visceral layer 20. It is formed by the right atrium. c. parietal layer & fibrous pericardium a. left border d. visceral layer & fibrous pericardium b. right border 12. It is a disorder characterized by an excessive c. lower border accumulation of fluid within the pericardial sac. d. apex 13. What are the 3 main manifestations of the above 21. What structure lies at the 3rd bump of the left disorder? The “Becks Triad” border of the heart? a. muffled lung sound, muffled heart sound, a. aorta hypertension b. pulmonary artery b. jugular vein distention, muffled heart sound, c. left atrium hypertension d. left ventricle c. jugular vein distention, hypotension, muffled 22. Identify the walls of the heart. 1. GREEN, 2. BLACK, lung sound 3. ORANGE d. jugular vein distention, muffled heart sound, hypotension 15. Identify the structure. RED RECTANGLE 16. Identify the structure. ORANGE RECTANGLE 23. It is the roughened or trabeculated by bundles of a muscle fiber. 24. What is the shape of the right ventricle when cut cross sectionally? 25. True or False. The tricuspid valve is composed of anterior and inferior cusps only. 26. True or False. The left atrium has crista terminalis. 27. True or False. The left ventricle has a circular shape when cut cross-sectionally. 28. Functions of Fibrous Cardiac Skeleton. Select all that apply. a. separate the muscular walls of the atria from those of ventricles b. support & attachment for the bases of valve cusps c. electrical insulation between atria and ventricles d. a & b only Page 12 of 13 CMED 1A CMED 1A Page 13 of 13 ANSWER KEY 1. B 2. A, B, D, E 3. Fibrous Pericardium 4. Sternopericardial Ligaments 5. Serous Pericardium 6. C 7. D 8. Transverse Sinus 9. Oblique Sinus 10. C 11. A 12. Cardiac Tamponade 13. D 14. A 15. Antrioventricular Groove 16. Interventricular Groove 17. False 18. False 19. A 20. B 21. C 22. 1.Epicardium, 2.Myocardium, 3.Endocardium 23. Musculi Pectinate 24. Crescent 25. False 26. Fale 27. True 28. A,B,C 3. Lecture Video Anatomy (7th ed.) Saunders Elsevier 2. Netter,Frank H. MD(2018) Atlas of Human Regions (10th ed.) Lippincott, Williams & Wilkins. 1. Snell, Richard (2012). Snell’s Clinical Anatomy by REFERENCES DR. LESLIE ASUNCION-VIADO | 01/04/21 (INTRODUCTION, FUNCTION, AND LOCATION) (003) HEART AND ITS COMPONENTS