L1. Anatomy of the Heart.pdf

Ana to m y T ea m 443 Anatomy of the Heart Cardiovascular Block Color Index Main Text Female Slides Male Slides Drs' Notes Important Extra info The Editing File Objectives Describe the shape of heart regarding: Apex, base, sternocostal and diaphragmatic surfaces. Describe the interior of heart chamb...

Ana to m y T ea m 443 Anatomy of the Heart Cardiovascular Block Color Index Main Text Female Slides Male Slides Drs' Notes Important Extra info The Editing File Objectives Describe the shape of heart regarding: Apex, base, sternocostal and diaphragmatic surfaces. Describe the interior of heart chambers: Right atrium, right ventricle, left atrium and left ventricle. List the orifices of the heart: Right atrioventricular (Tricuspid) orifice, pulmonary orifice, left atrioventricular (Mitral) orifice, aortic orifice. Describe the innervation of the heart. Briefly describe the conduction system of the heart. You can find more quizzes by Clicking HERE! Special Thanks to Saleh Aljanah and Nawaf Alqahtani! You can find Atlas by Clicking HERE! The Heart Overview It lies in the middle mediastinum. It is surrounded by a fibroserous sac called pericardium which is differentiated into: 1- Outer fibrous layer (Fibrous pericardium). 2- Inner serous sac (Serous pericardium). It is somewhat pyramidal in shape. Features of the heart External features: Apex Internal features: Consists of 4 chambers: Sterno-costal (anterior surface) 2 atria (right & left) Diaphragmatic (inferior surface) 2 ventricles (right & left) Borders of the Heart Base (posterior surface) Orifices Upper Border ○ ○ Formed by the 2 atria. Concealed by ascending aorta & pulmonary trunk. Right Border ○ Formed by the right atrium. Lower Border ○ Formed mainly by the right ventricle + apical part of the left ventricle. Left Border ○ Formed mainly by the left ventricle + auricle of the left atrium. External Features of the Heart Apex of the Heart Base of the Heart (Posterior Surface) SAQ Directed downwards, forwards, and to the left. It is formed by the left ventricle. Lies at the level of left 5th intercostal space, approximately 3.5 inch from midline. ○ Note that: 1- Base of the heart is called the base because the heart is pyramid in shape. 2- The base lies opposite to the apex. 3- The heart does not rest on its base; it rests on its diaphragmatic (inferior) surface. 1 SAQ It is formed by the 2 atria, mainly left atrium, into which open the 4 pulmonary veins. It is directed backwards. Lies opposite middle thoracic vertebrae (T5-T7). It is separated from the vertebral column by descending aorta, esophagus, and oblique sinus of pericardium. Bounded inferiorly by the posterior part of coronary sulcus, which lodges the coronary sinus. 2 Left Atrium Base Coronary sinus Sterno-costal (Anterior) Surface Divided by coronary (atrio-ventricular) groove into: ❖ Atrial part: Formed mainly by the right atrium. ❖ Ventricular part: The right 2/3 is formed by right ventricle, while the left 1/3 is formed by left ventricle. So, it is also formed of some of the left ventricle. The coronary groove lodges the right coronary artery. The 2 ventricles are separated by anterior interventricular groove, which lodges: 1. Anterior interventricular artery (a branch of the left coronary artery) 2. Great cardiac vein 3 4 Diaphragmatic (Inferior) Surface Formed by the 2 ventricles, mainly left ventricle (left 2/3) + small portion of right ventricle. Slightly concave as it rests on diaphragm. Directed inferiorly & backward. Separated from base of heart by posterior part of coronary sulcus. The 2-ventricles are separated by posterior interventricular groove which lodges: 1. Posterior interventricular artery (a branch of the right coronary artery) 2. Middle cardiac vein Chambers of the Heart SAQ The heart is divided by vertical septa into four chambers: the right and left atria, and the right and left ventricles. The right atrium lies anterior to the left atrium, and the right ventricle lies anterior to the left ventricle. 1- Right Atrium The right atrium consists of a main cavity and a small outpouching, the auricle. On the outside of the heart, at the junction between the right atrium and the right auricle, is a vertical groove, the sulcus terminalis, which on the inside forms a ridge, the crista terminalis. Crista terminalis divides the right atrium into: 1. Anterior part: It is rough and trabeculated by bundles of muscle fibres (musculi pectinati). 2. Posterior part (sinus venarum): It is smooth. The interatrial septum carries an oval depression called Fossa ovalis. The margin of this depression is called Anulus ovalis. The blood leaves right atrium to right ventricle via tricuspid valve. Openings in right atrium 1. 2. 3. 4. SVC* → has no valve IVC* → guarded by a valve Coronary sinus → has a well-defined valve Right atrioventricular orifice: lies anterior to IVC opening, it is surrounded by a fibrous ring which gives attachment to the tricuspid valve. 5. Small orifices of small veins. *SVC: Superior vena cava. *IVC: Inferior vena cava. SAQ Chambers of the Heart 2- Left Atrium The left atrium communicates with the left ventricle through the left atrioventricular orifice, and the left ventricle with the aorta through the aortic orifice. It forms the greater part of base of heart. Its wall is smooth, except for small musculi pectinati in the left auricle. It receives 4 pulmonary veins, which have no valves. Sends blood to left ventricle through the left atrioventricular orifice, which is guarded by mitral valve (Bicuspid valve). Chambers of the Heart Ventricles 1- Right Ventricle ❖ Its wall is thinner than that of left ventricle. ❖ Its wall contains projections called trabeculae carnae. ❖ The right ventricle communicates with: 1. Right atrium through right atrioventricular orifice. 2. Pulmonary trunk through pulmonary orifice. ❖ The part (cavity) of right ventricle leading to the pulmonary trunk becomes funnel shaped, and referred as the infundibulum. ❖ The wall of infundibulum (Conus Arteriosus) is smooth and contains no trabeculae. ❖ Large projections arise from the walls, and are called papillary muscles Anterior papillary muscle Posterior papillary muscle Septal papillary muscle ❖ Each papillary muscle is attached to the cusps of tricuspid valve by tendinous threads called chordae tendinae. ❖ Interventricular septum is connected to anterior papillary muscle by a muscular band called moderator band. ❖ Blood leaves the right ventricle to pulmonary trunk through pulmonary orifice. Chambers of the Heart Ventricles 2- Left Ventricle Its wall is thicker than that of right ventricle. It receives blood from left atrium through left atrio-ventricular orifice which is guarded by mitral valve (bicuspid). Its wall contains: 1. Trabeculae carneae 2. 2 large papillary muscles: Anterior Posterior ❖ They are attached by chordae tendineae to cusps of mitral valve. The blood leaves the left ventricle to the ascending aorta through the aortic orifice. The part of left ventricle leading to ascending aorta is called aortic vestibule. The wall of this part is fibrous and smooth. Pericardial Sinuses and the Orifices Female Slides Pericardial Sinuses Transverse Sinus It is a recess of serous pericardium between ascending aorta & pulmonary trunk anteriorly, and upper parts of 2 atria & S.V.C posteriorly. Two Sinuses Oblique Sinus It lies posterior to the heart. It is a recess of serous pericardium behind the base of heart (left atrium), and it separates the base from descending aorta, esophagus & vertebral column. Orifices Orifices Semilunar orifices Pulmonary Orifice Aortic Orifice Atrioventricular orifices Right Tricuspid Orifice Left Mitral (bicuspid) Orifice The Orifices Pulmonary Orifice ❏ ❏ ❏ ❏ Right Tricuspid Orifice Aortic Orifice ❏ ❏ - ❏ ❏ ❏ ❏ ❏ Left Mitral (bicuspid) Orifice ❏ ❏ ❏ ❏ ❏ Surrounded by a fibrous ring which gives attachment to the cusps of the pulmonary valve. The valve is formed of 3 semilunar cusps: Two anterior One posterior The valves are concave superiorly and convex inferiorly. No chordae tendineae or papillary muscles are attached to these cusps. Surrounded by a fibrous ring which gives attachment to the cusps of the aortic valve. Aortic valve is formed of 3 semilunar cusps which are similar to those of pulmonary valve, but the position of the cusps differs being: One anterior Two posterior Right atrio-ventricular orifice. About one inch wide, admitting tips of 3 fingers. It is guarded by a fibrous ring which gives attachment to the cusps of tricuspid valve. It has 3-cusps: anterior – posterior – septal or medial. The atrial surface of the cusps are smooth, while their ventricular surfaces give attachment to the chordae tendinae (connect cusps with papillary muscle). Smaller than the right, admitting only tips of 2 fingers. Guarded by a mitral valve. Surrounded by a fibrous ring which gives attachment to the cusps of mitral valve. Mitral valve is composed of 2 cusps: Anterior cusp: lies anteriorly and to right. Posterior cusp: lies posteriorly and to left. The atrial surfaces of the cusps are smooth, while ventricular surfaces give attachment to chordae tendinae. Nerve Supply and Conduction System of the Heart MCQ SAQ Nerve Supply By sympathetic & parasympathetic fibers via the cardiac plexus situated below arch of aorta. Sympathetic fibres ❏ Arise from the cervical & upper thoracic ganglia of sympathetic trunks. ❏ Accelerate heart rate. SAQ MCQ Conduction System Parasympathetic fibres Postganglionic fibres ❏ It reach heart along SAN, AVN & nerve plexus around coronary arteries. ❏ Arise from the vagus nerves. ❏ Slow heart rate (constriction of coronary arteries). The question could be “ Enumerate the intrinsic conduction nodal system components and write their location: “ 1. SA node located in the right atrium. 2. AV node etc… The beating of the heart is regulated by the intrinsic conduction (nodal) system. Its function is to ensure that the chambers of the heart contract in the proper rhythm and sequence: Sinoatrial (SA) node It is the main center located in the right atrium. It is called the pacemaker of the heart, because it generates the impulse. Atrioventricular (AV) node It is located at the junction of the atria and the ventricles. Atrioventricular (AV) bundle (bundle of His) It is located in the interventricular septum. Purkinje fibers They are located inside the walls of the ventricles. MCQs Q1. The base of the heart is mainly formed by: A. Left atrium B. Right atrium C. Left ventricle D. Right ventricle Q2. Which of the following connects papillary muscle with the cuspid? A. Crista terminalis B. Chordae tendineae C. Trabeculae carneae D. Moderator band Q3. Why does the left ventricle have a thicker wall than the right ventricle? A. Not normal caused by B. Because of a genetic C. Because it is the pathological hypertrophy disorder pumping chamber D. Unknown Q4. Which of the following is located in the interventricular septum? A. Bachmann’s bundle B. AV node C. Purkinje fibers D. Bundle of His (AV bundle) Q5. How can sympathetic nervous system affect the heart rate? A. Accelerate HR B. Slow HR C. A and B D. None A1. A A2. B A3. C A4. D A5. A FOR THE Q BANK FILE FOR ANKI FLASHCARDS OR CLICK HERE OR CLICK HERE Important SAQs in this file Team Leaders Remaz Almahmoud Moath Alhudaif Team Members Aishah Boureggah Nazmi M Alqutub Aroub Almahmoud Zeyad Alotaibi Aseel Alshehri Norah Almohaimeed Lama Alotaibi Dana Alkheliwi Renad Alshehri Razan Alaqeel Rahaf Alrasheed Abdulaziz Al Fuhayd Khalid Alsobei Talal Alkhamis Mohammed Alqutub Mohammad Alsalamah Mohammed Alarfaj Sara Alharbi Norah Almania Special Thanks to Aleen Alkulyah for the Wonderful Design! [email protected] Ana to m y T ea m 443