CVS-1 PDF - Cardiovascular System Anatomy - Assiut University

PMS Block Anatomy THE CARDIOVASCULAR SYSTEM By Dr Haidy refaat Department of human Anatomy and Embryology Faculty of Medicine Assiut University  CARDIOVASCULAR SYSTEM Definition It is the transport system thr...

PMS Block Anatomy THE CARDIOVASCULAR SYSTEM By Dr Haidy refaat Department of human Anatomy and Embryology Faculty of Medicine Assiut University  CARDIOVASCULAR SYSTEM Definition It is the transport system through which the nutrients & oxygen are conveyed to different tissues of the body to be utilized and the metabolites are conveyed to places where can be expelled Components 1- Heart 2-Arteries 3-Veins 4-capillaries  The heart - Pericardium: Pericardium The pericardium is a sac surrounds the heart. It is formed of the following 2 parts: 1. Fibrous pericardium: The heart lies inside a fibrous sac for protection. 2. Serous pericardium: It is serous sac formed of 2 layers, a. Visceral layer: adherent to the walls of the heart. b. Parietal layer: lines the fibrous pericardium Serous pericardium Fibrous pericardium - The pericardial cavity lies between the visceral and parietal layers which contains a thin film of serous fluid to prevent friction between visceral and parietal layer.  The Heart - The heart is conical in shape, has base, apex, 2 surfaces (stern-costal and diaphragmatic) and 4 borders. - The heart consists of 4 chamber right and left atria and right and left ventricles. Base: It is formed by both atria (mainly the left atrium) Apex: It is formed by left ventricle only; it is directed downwards, forwards and to the left and lay in the 5th intercostal space, The heart - Surfaces: 1. The sternocostal surface (anterior); Is formed mostly by ventricular part( the right ventricle2/3 & left ventricles1/3) and atrial part auricle of right atrium and left auricle. On this surface the right ventricles is separated from the right atrium by the coronary groove (anterior atrioventricular groove). Also on this surface the two ventricles are separated by the anterior interventricular groove. Coronary groove Anterior Interventricular groove  The heart - Surfaces: 2. The diaphragmatic surface; (inferior) lies over the diaphragm , Left ventricle It is formed by the, right ventricle (⅓) and left ventricle (⅔), separated by posterior interventricular groove. Right ventricle Posterior interventricular groove Diaphragmatic surface Posterior view The heart - Surfaces: 3. The base; (posterior surface); It is formed mainly by the left atrium, small portion of the right atrium. Left atrium Right atrium  Borders of the heart - The heart has 4 borders:  Upper border: formed by both atria (mainly the left).  Right border: formed by right atrium (only).  Lower border: formed by: a. Right ventricle b. Small part of left ventricle which form the apex,  Left border: formed by: (Left ventricle and Left auricle). Borders of the heart The heart - Chambers: Left ventricle Anterior view Posterior view The heart - Chambers: The heart is divided by 2 septa in to 4 chambers. The septa are interventricular septun( IVS ) between the right and left ventricles and the interatrial septum ( IAS) between the right and left atria. Left Atrium Interatrial septum Right Atrium Left Ventricle Right Ventricle Interventricular septum Coronal section of the heart The heart – Right atrium:  It is quadrilateral in shape, it receives deoxygenated blood from the body.  It forms the right border, extends between the superior & inferior vena cavae It has a smooth posterior part& rough anterior part anterior part extend to the auricle posterior part The heart – Right atrium: Openings in the right atrium;  Right aterioventricular opening (between the right artrium & right ventricle)  Opening of the inferior vena cava,  Opening of the superior vena cava  Opening of the coronary sinus Right artioventricular opening “Tricuspid valve” Opening of SVC Opening of IVC Opening of coronary sinus The heart – Left atrium:  It forms the base of the heart and lies behind the right atrium.  It receives the 4 pulmonary veins, two from each lung.  It is connected to the left ventricle by the left artioventricular opening which is guarded by the mitral valve (bicuspid). Left Pulmonary veins Right Pulmonary veins Left atrium The heart – Right ventricle: Chordae tendineae The wall of the ventricle is muscular and thicker than the atrial wall Some bundles of these muscles, the papillary muscle project inward from the ventricular wall & their apices are connected by fibrous cord, to the cusps of the tricuspid valve. (3-papillary muscles in this ventricle) Papillary muscle Trabeculae carneae  The heart – Left ventricle:  Situated posterior to the right ventricle.  It forms the apex of the heart.  The walls are three times thicker than the right ventricle.  There are 2-papillary muscles attached to each cusp (bicuspid valve)  The ventricle communicates with the left atrium through the left aterioventricular opening which is guarded by the mitral valve.  The out follow of the blood from this chamber enters the aorta which is guarded by valve that are composed of three semi lunar cusps. The heart – valves of the heart: The heart – conducting system: Sympathetic & Parasympathetic systems regulate the work of the heart.  Sympathetic stimulation increases the rate and the force of heart contractions.  Parasympathetic stimulation decreases the heart rate. The heart – conducting system:  Electrical impulses arise from modified heart muscle (the myocardium) and cause the heart to contract.  This electrical signal begins in the Sinoatrial (SA) node, located at the lateral wall right atrium. The SA node is the pacemaker.  Impulse from the SA node travels through the walls of the right atrium to the atrioventricular (AV) node.  From the AV node impulses are distributed to the two ventricles through the atrioventricular (AV) bundle. The heart – Arterial blood supply: Ascending aorta The heart is supplied by two coronary arteries that arise from the beginning of the ascending aorta and supply the muscle and other tissues of the heart. Right coronary artery Left coronary artery The heart – venous drainage: Coronary sinus The returning venous blood passes through the cardiac veins, most of which empty into the coronary sinus. This coronary sinus is large venous structure is located on the posterior surface of the heart between the left atrium and left ventricle. The coronary sinus empties into the right atrium near the opening of the inferior vena Cardiac veins cava. Posterior view  Blood vessels  The heart and blood vessels make up the blood transportation network.  The blood vessels are connected with the heart on one side and with the tissues of the body on the other side.  The left ventricle of the heart gives rise to the aorta. This artery gives off branches and these divide repeatedly until minute arteries called arterioles are formed. These arterioles again subdivide to form a network of capillaries (or sinusoids) called capillary bed.  From these capillaries the blood is collected into minute veins, called venules which unite to form larger veins, finally the Superior vena cava and inferior vena cava join the right atrium of the heart.  Thus the vessels are classified into arteries, arterioles, capillaries, venules and veins. Arteries: It is vessels which carry blood away from the heart.  The distribution of systemic arteries is like a high branching tree. The common trunk is formed by the aorta. The vessels give rise to several branches in succession.  Arteries do not always end in capillaries. In many cases they unite with one another forming anastomosis.  Characteristic features 1- thick wall 2-carry oxygenated blood except 3-deeply situated 5-Have no valves Anastomosis: The term "anastomosis" means the communication between neighboring vessels. 1. Arterial anastomosis It is between arteries and is found mainly at the following sites: (Around joints of the limbs, In the hand and foot, At the base of the brain, In the abdomen) 2 types Actual Potential 2-venous anastomosis 3-arteriovenous anastomosis  Palpable arteries Can be palpated through the skin. Examples: ……………………  An end arteries End-arteries are arteries which do not anastomose with neighboring arteries or arteries with insufficient anastomosis.  Examples: (Central artery of the retina, Cerebral arteries of the brain, Arteries within the kidney and spleen and Coronary arteries of the heart) Tortuous arteries Wavy arteries: These are arteries which have a wavy course.  Examples: (facial, uterine, splenic and lingual artery). Veins : It is vessels which carry blood to the heart.  The veins run either superficially just under the skin and are called superficial veins, or run deeply beneath the deep fascia (between muscles) and are called deep veins. Superficial veins are used for intravenous injection. Characteristic features 1- thin wall 2-carry non oxygenated blood except 3-superficialy situated 5-Have valves except in….. Differences between arteries and veins: 1- Veins progressively increase in size by receiving more tributaries. 2- Their walls are thinner than the corresponding arteries. 3- Veins don't pulsate, while arteries pulsate. 4- Veins contain valves, while arteries do not. Blood circulations The blood circulates into a closed system of vessels. There are 3 types of circulation: 1. Systemic circulation: It begins in the left ventricle of the heart where oxygenated blood flows into the aorta and its branches to reach all tissues of the body then return back to the right atrium of the heart through superior and inferior vena cava. 2. Pulmonary circulation: It begins in the right ventricle where the non-oxygenated blood passes through the pulmonary trunk then through the 2 pulmonary arteries to enter the 2 lungs where oxygenation of the blood occur then the oxygenated blood return to the left atrium of the heart by 4 pulmonary veins. 3. Portal Circulation: The venous blood from the gastrointestinal tract and the spleen passes through the portal vein to enter the liver. The portal vein divides repeatedly inside the liver to end in the liver sinusoids. These sinusoids lead to the hepatic veins which join the inferior vena cava then enters the right atrium of the heart.  Most nutrients absorbed by the intestine pass through the liver, which serves as a filter that can remove Aor potentially harmful xenobiotics before ta they get into the systematic circulation. Capillari Hepatic es of vein liver Inferior vena cava Hepatic artery Hepatic portal vein Digestive tract arteries Capillaries of digestive tract: stomach, intestines, Fig.24: portal vein and circulation pancreas, and spleon  The main arteries of the body: Left common Branches of Aorta carotid a. Branches of Ascending Aorta 1. 1-right coronary artery 2. 2-Left coronary artery Branches of arch of Aorta 1. Brachiocephalic trunk 2. Left common carotid a. 3. Left subclavian a, Brachiocephalic Left trunk subclavian  The right and left common carotid arteries each divides into internal carotid artery (for brain) & external carotid artery (for face, scalp & neck).  The main arteries of the body:  The arch of the aorta then descends down through the thorax to form the thoracic aorta (supplies the thoracic wall & lungs)  The thoracic aorta pierces the diaphragm to give the abdominal aorta (supplies the GIT, liver, pancreas, spleen, & two kidneys)  Then at the level of 4th lumbar vertebrae the abdominal aorta divides into two large branches the right & left common iliac arteries.  Each common iliac artery divides into internal iliac (supplies pelvic organs like uterus, rectum,urinary bladder) and external iliac (for the lower limbs).  1 Branches of Abdominal 2 Aorta 3 A- Branches to supply the abdominal viscera: 1) Celiac 4 2) Suprarenal 5 3) Superior mesenteric 4) Renal 6 5) Gonadal (Ovarian & testicular) 6) Inferior mesenteric B- Lumbar arteries provide blood for the muscles and spinal cord Lumbar arteries Right common carotid Left common carotid Left subclavian Right subclavian Arch of aorta Abdominal aorta Right common iliac External iliac Internal iliac  Lymphatic system Lymph fluid Clear colorless fluid lymph is similar in composition to blood plasma. It is derived from excess tissue fluid of filtrating blood plasma as the interstitial fluid begins to accumulate, Lymph capillaries The smaller lymphatic vessels, which take up the fluids, are called lymph capillaries. Lymph vessels The larger lymphatic vessels have muscles in their walls which helps them gently and slowly pulsate. are found in all regions of the body except the bone marrow, central nervous system, and tissues, such as the epidermis, that lack blood vessels Lymph nodes are small lumps of tissue that contain white blood cells, which fight infection. Size vary Found in groups Questions??