Anatomy of the Heart PDF

The heart is part of the circulatory system. It circulates blood containing nutrients and oxygen to the tissues. The blood is able to move because of the pressure released by the heart’s pumping action. Structure and Functions of Blood vessels untie 0 Blood vessels are tubular channels, which carry...

The heart is part of the circulatory system. It circulates blood containing nutrients and oxygen to the tissues. The blood is able to move because of the pressure released by the heart’s pumping action. Structure and Functions of Blood vessels untie 0 Blood vessels are tubular channels, which carry nutrients to the tissue and metabolites back from the tissue into circulation. Anatomy of the heart-chambers, valves, conducting system, coronary circulation; Structure and functions of blood vessels Vascular tree Elastic artery (aorta) → Muscular arteries → Arteriole → Capillaries → Venule → Medium sized vein → Large vein (Vena cavae) Tuesday, 23rd May 2024, 2 to 2.50 p.m. By Dr. Sampath Madhyastha 85 Arteries Carry blood away from the heart. They branch like trees on their way to different parts of the body. Arteries are thick walled, being uniformly thicker than the accompanying veins. The lumen is smaller than that of the veins accompanying it. Arteries do not have any valves. Veins They bring blood from various tissues of the body back into the heart. The veins are formed by the union of many tributaries (like a river). Veins are thin walled, being thinner than the arteries. Their lumen is larger. Veins have ‘valves’ which are reduplications of endothelium. They maintain the unidirectional flow of blood even against gravity. However, some of the veins do not have valves.. Capillaries simpiesgamuos These are microscopic blood vessels within the tissue. They have single layer of endothelial cells resting on a basement membrane, without any outer coats. Capillaries have arterial and venous ends. Three types of capillaries in the body: continuous capillaries (present in skeletal muscle and brain), fenestrated capillaries (present in kidney, intestine and endocrine glands) and sinusoids (present in lymphoid organs) ig Wall of the blood vessels depending ontherumen From inside to outside 1. Tunica intima 2. Tunica media 3. Tunica adventitia These layers consists of collagen fibres, elastic fibres and smooth muscles. The distribution of these tissue differs in artery and veins and also among the three different layers of the vessel. Tunica intima lined by endothelial cells Tunica media Intern Tunica adventitia Tunica intima: This layer is lined by endothelium, which is comprised of simple squamous epithelial cells. Just deep to the endothelium are a basement membrane and a layer of subendothelial connective tissue that offers support to the overlying cells. Tunica media: The middle muscular layer of the blood vessel is the tunica media. It also contains elastic and few collagen fibers. The muscle of this layer is smooth muscle that is fitted with alpha- and beta-adrenergic receptors. These receptors are innervated primarily by the sympathetic nervous system. Tunica adventitia: The outermost layer of the blood vessels is the tunica adventitia, also known as the tunica externa. This layer is primarily composed of collagen and elastic connective tissue (in arteries). This external layer is responsible for anchoring the vessels to adjacent organs. grow.name 3 Large sized artery has more elastic fibers Medium sized artery has more smooth muscles ramen A schematic representation showing layers of the blood vessels gradualchanginstructor Heart has four chambers: two atria and two ventricles Location The heart is placed obliquely in the thoracic cavity (middle mediastinum) between the two lungs and behind the sternum Measurement middle The normal adult heart measures about 12cm vertically and about 6cm anteroposteriorly. It is slightly larger than one’s own clenched fist. Heart is covered by a fibro-serous membrane called pericardium Right atrium - receives oxygen-poor blood from the body and pumps it to the right ventricle. Right ventricle - pumps the oxygen-poor blood to the lungs. Left atrium - receives oxygen-rich blood from the lungs and pumps it to the left ventricle. Left ventricle - pumps the oxygen-rich blood to the body. line fiF nm i Pericardium Circulation of Blood Right atrium receives deoxygenated blood from the whole body through the superior and inferior vena cavae and coronary sinus. When it contracts, the blood passes to the right ventricle through the right atrioventricular orifice. When the right ventricle contracts, blood passes to the lungs through the pulmonary trunk and pulmonary arteries. In the lungs it gets purified, returns to the left atrium through the pulmonary veins and reaches the left ventricle through the left atrioventricular orifice. When the left ventricle contracts, the blood passes to the aorta and through its branches, to the different parts of the body. Inner serous pericardium Outer fibrous pericardium Outer parietal layer Inner visceral layer (epicardium) eviction minimize Pericardial cavity: Space filled with thin fluid between parietal and visceral layers of the serous pericardium. Oblique and transverse sinuses are the part of the pericardial cavity. The inflammation of pericardium is called pericarditis. The accumulation of the fluid in the pericardial cavity is called pericardial effusion E to a trig EE É If Interior of the right atrium The cavity of the right atrium presents three walls (anterior, posterior and septal). 1. Anterior rough wall Crista terminalis is a smooth muscular ridge on the right side Musculi pectinati (Pectinate muscles) are parallelly placed muscular ridges extending from crista terminalis. 2. Posterior smooth wall (Sinus venarum) It presents the following openings for major veins, which bring deoxygenated blood from the body and the heart itself. Opening of the superior vena cava – in the upper part Opening of the inferior vena cava – in the lower part. This opening is guarded by a semilunar valve called ‘Eustachian valve’ which presents right and left horns. Opening of coronary sinus: The venous blood from musculature of the heart is drained into coronary sinus 3. Septal wall It separates the right atrium from left atrium, which is placed posteriorly and to the left. wqedoister Pulmonary valve Interior of the right ventricle I IIF P O Right auricle Inflowing rough part Right atrium proper Right atrioventricular orifice with tricuspid valve Trabeculae carneae (anterior, posterior & septal papillary muscles É External view of the heart Crista terminalis Opening of the SVC Opening of the IVC Eustachian valve q Pectinate muscles Opening of the coronary sinus Interior of the right atrium Smooth outflowing part Supraventricular crest Outflowing smooth part inanna QQ 8E.es Tricuspid valve Infundibulum Summit of the infundibulum presents three semilunar cusps (pulmonary valve). Above the cusps it continues as pulmonary artery Septomarginal trabeculae Tendinous cords Anterior papillary muscle Ridge Interior of the right ventricle Right atrio-ventricular/Tricuspid valve It guards the right atrio-ventricular orifice. It consists of three cusps or leaflets. They are named anterior, posterior and septal. They are attached to the corresponding sides of the orifice. The other end (free margin) of each cusp extends into the cavity of right ventricle. This free margin provides attachments to the chordae tendineae (tendinous cords). The chordae tendineae arise from the apical part of the papillary muscles present in the rough part of the right ventricle. Posterior papillary muscle (cut) Septal cusp Septal papillary muscle Anterior cusp Posterior cusp Tricuspid valve Anterior papillary Posterior papillary muscle muscle (cut) IT.gg me Interior of the left auricle Interior of the Left atrium The posterior wall of the left atrium receives the openings of four valveless pulmonary veins Anteriorly, it communicates with left ventricle through left atrio-ventricular orifice, which is guarded by ‘mitral valve’. w Thick muscular wall of the left ventricle Openings of pulmonary veins Interior of the left ventricle o Inflowing rough part Left atrio-ventricular orifice with mitral valve Trabeculae carneae (anterior & posterior papillary muscles so Lunate fossa Outflowing smooth part Left ventricle & left atrium Aortic vestibule Summit of the vestibule presents three semilunar cusps (aortic valve). Above the cusps it continues as ascending aorta Tendinous cords Anterior papillary muscle Cusps Mitral/bicuspid valve It consists of two cusps anterior and posterior. These cusps are attached to the margin of left atrio-ventricular orifice. Their free ends provide attachment to the chordae tendineae. These chordae tendineae arise from papillary muscles present in the left ventricle. noting Left coronary artery Origin: Left posterior aortic sinus of the ascending aorta Branches The anterior interventricular artery (LAD artery): 1. Right anterior ventricular branches 2. Left anterior ventricular branches: one of these branches is large and is called ‘left diagonal artery’. 3. Left conus artery: It forms an arterial ring around the pulmonary trunk along with right conus artery 4. Septal branches: Supply anterior 2/3rd of the interventricular septum. Circumflex artery: 1. Left marginal artery: It descends along the left border up to the apex of the heart. 2. Anterior and posterior ventricular branches 3. Atrial branches are classified into anterior, posterior and lateral groups Aortic vestibule/smooth portion of the left ventricle Posterior papillary muscle I ji i Right coronary artery Origin: Anterior aortic sinus of the ascending aorta Branches 1. Right conus artery (3rd coronary artery):arterial circle around the pulmonary trunk. 2. Atrial branches: anterior, lateral and posterior groups. Artery to the sinuatrial node’(In 65%). 3. Ventricular branches: anterior groups and posterior groups 4. Right marginal artery 5. Posterior interventricular artery (PDA): It gives many septal branches and one of the first septal branch supplies AV node. Septal branches supply posterior1/3rd of the interventricular septum Right atrium Distribution of left coronary artery Left atrium Greater part of the left ventricle except at the posterior interventricular groove. Small part of the right ventricle at the anterior interventricular groove. A part of the left branch of the AV bundle. Anterior 2/3rd of the interventricular septum Coronary sinus Rat WE Right coronary artery (2nd segment) Posterior view Posterior interventricular artery (PDA) Left coronary artery n Circumflex artery Right coronary artery (1st segment) Anterior view Veins of the Heart Left marginal artery Artery to the SA node Distribution of right coronary artery Right atrium Right marginal Greater part of the right ventricle except the right ventricle at the anterior artery interventricular groove. Small portion of left ventricle adjoining posterior interventricular groove. The entire conducting system of the heart except the left branch of the AV bundle. Posterior 1/3rd of the interventricular septum Left lateral view Circumflex artery É Blood supply to the heart Arterial supply: The blood within the chambers of the heart will only supply the endocardium and subendocardial tissue. The thick musculature of the heart needs additional source of arterial supply. Heart is supplied by right and left coronary arteries. Anterior interventricular artery (LAD) Left diagonal artery Itrasity Nerve supply to the heart Though the cardiac muscle contracts rhythmically and automatically, the nerves supplying the heart alter the cardiac rate. The sympathetic and parasympathetic fibers supplying the heart form two cardiac plexuses (superficial and deep). The fibers arising from these plexus follow the coronary arteries and to the components of conducting system, particularly the SA node. Sympathetic source: The preganglionic fibers arise from upper 5 or 6 thoracic segment (T1-T6) of the spinal cord (lateral horn/intermediate horn). Sympathetic fibers increase the heart rate, impulse conduction, force of contraction (increases cardiac output) Parasympathetic source: It is derived from right and left vagus nerves. These are preganglionic (or presynaptic) fibers, which make synapses with small ganglions close to the myocardium. Parasympathetic stimulation slows the heart rate, reduces the force of contraction and constricts the coronary arteries (Post synaptic parasympathetic fibers release acetyl choline). main g Conducting system of the Heart Conducting system consists of specialized myocytes which connect ‘pacemaker’ regions of the heart E Atrio-ventricular node (AV node) It is located in the triangle of Koch, which is placed in the lower part of the inter atrial septum. Branches from arch of aorta 1. Brachiocephalic trunk which gives right common carotid and right subclavian arteries 2. Left common carotid artery 3. Left subclavian artery Peguero AV bundle mfs Cardiac muscles Abdominal aorta EQ AV node Atrio-ventricular bundle (AV bundle/bundle of His) It begins from the AV node traverses the interventricular septum and then divides into right and left branches. Angina pectoris: Pain in the chest due to inadequate blood supply to myocardium (ischemia). Myocardial infarction (MI): There is a complete block in the coronary artery either due to thrombus (coagulation of blood) or embolus (obstruction by thrombus, fat cells or air) formation on the atheromatous patch in the vessel. Coronary angiography: Coronary arteries are visualized after injecting a contrast medium into them Pacemakers Thoracic aorta Ia SA node Purkinje fibers form a subendocardial plexus. They are larger and somewhat paler than ordinary myocytes. Nerve impulses Arch of aorta Purkinje Sinuatrial node (SA node) It is known as the ‘pacemaker’ of the heart. It is situated in the upper part of the crista terminalis. The impulses from the SA node reach atrio-ventricular node. Vasomotor centers of the brainstem Ascending aorta ofHis bundle Common iliac arteries External iliac artery Right branch of the AV bundle in moderator band Blood supply of the Brain 1. Right and left internal carotid artery 2. Right and left vertebral artery (Branches from subclavian artery) Internal iliac artery Blood supply of the Neck 1. Right and left external carotid arteries 2. Branches from subclavian arteries Right internal carotid artery Right external carotid artery HIM Right vertebral artery Right common carotid artery Right subclavian artery Ea Blood supply of the Upper Limb 1. Axillary artery (continuation of subclavian artery) in the arm pit 2. Brachial artery (in the arm) 3. Radial and ulnar arteries (in the forearm) 4. Palmar arterial arches (Hand) Axillary artery Blood supply of the thorax 1. Thoracic wall-Branches from thoracic aorta and internal thoracic artery (branch from subclavian artery 2. Heart-Right and left coronary arteries 3. Lungs – Right and left Pulmonary arteries (venous blood + bronchial arteries (arterial blood) Left subclavian artery Brachiocephalic trunk Brachial artery Left common carotid artery (cut) Arch of aorta Thoracic aorta Posterior intercostal arteries Radial artery Ulnar artery Abdominal aorta Blood supply of the Abdominal organs Branches from the abdominal aorta 1. Coeliac artery & its branches – Splenic, hepatic & left gastric 2. Superior mesenteric artery – mainly supplying small intestine 3. Inferior mesenteric artery – mainly supplies large intestine 4. Renal arteries-supplies kidney 5. Gonadal arteries (testicular or ovarian artery) Coeliac artery (cut) Superior mesenteric artery (cut) Blood supply of the Lower Limb 1. Femoral artery (continuation of external iliac artery) in the thigh 2. Popliteal artery (at the back of the knee) 3. Anterior & posterior tibial arteries (in the le) 4. Dorsalis pedis artery + Plantar arches (Foot) External iliac artery Femoral artery Profunda femoris artery Renal artery Abdominal aorta Gonadal artery Blood supply of the Pelvic organs Internal iliac artery Inferior mesenteric artery (cut) Left common iliac artery Femoral artery Left internal iliac artery Superior mesenteric artery Inferior mesenteric artery Left external iliac artery Popliteal artery Anterior tibial artery Posterior tibial artery Is Which of the following best describes the feature of an artery? A. They bring blood from various tissues of the body back into the heart B. The are formed by the union of many tributaries C. They have valves D. Their wall is uniformly thick manza The continuous capillaries are found in which of these structure? A. Skeletal muscle B. Kidney C. Intestine D. Endocrine glands sas Presence of pectinate muscle is a feature of which chamber of the heart? A. Left atrium B. Left ventricle C. Right atrium D. Right ventricle Which artery gives origin to the coronary arteries? A. Arch of aorta B. Brachiocephalic artery/trunk C. Ascending aorta D. Thoracic aorta Which of the following structure of the heart initially receive nerve fibers? A. Purkinje fibers B. SA node C. AV node D. AV bundle 0 Which of the following is the effect of stimulating sympathetic nerves of the heart? A. Slows the heart rate B. Reduces the force of contraction C. Utilize acetyl choline at the post-synaptic terminal D. Increase the impulse conduction o