Cardiovascular System I PDF

CARDIOVASCULAR SYSTEM I Zaitunnatakhin Zamli 2 Learning outcomes The student should be able to:  Name the various parts of heart.  Describe gross and histological features of the heart.  Describe the orientation of heart in the mediastinum.  Describe the structure...

CARDIOVASCULAR SYSTEM I Zaitunnatakhin Zamli 2 Learning outcomes The student should be able to:  Name the various parts of heart.  Describe gross and histological features of the heart.  Describe the orientation of heart in the mediastinum.  Describe the structures that form the heart chambers and wall.  Describe the heart blood supply. PARTS & ORIENTATION OF HEART 4 INTRODUCTION MAJOR COMPONENTS: ▸ Blood ▸ Blood vessels ▸ Heart GENERAL FEATURES OF HEART: ▸ muscular organ. ▸ pumping blood. ▸ size ~ a clenched fist (~12 cm long, 9 cm wide at its broadest point, 6 cm thick). ▸ location – in mediastinum. 5 PARTS AND ORIENTATION OF HEART PARTS OF HEART: ▸ Base – 3rd costal cartilage ▸ Apex – 5th intercostal space ORIENTATION OF HEART: ▸ The heart rotated to the left around its long axis. ▸ The apex is pointed inferoanteriorly. ▸ Anterior surface - posterior to sternum and ribs. ▸ Inferior surface - resting on the diaphragm. ▸ R and L border - faces R and L lung, respectively. 7 SUPERFICIAL ANATOMY OF HEART STRUCTURE OF HEART 9 STRUCTURE OF HEART - PERICARDIUM ▸ Serous membrane that lining the pericardial cavity. ▸ Visceral and parietal pericardium. ▸ Pericardial cavity fills with pericardial fluid. 10 11 STRUCTURE OF HEART – HEART WALL 1. Epicardium  …………… pericardium  consists of mesothelium and loose ct. 2. Myocardium  muscular wall that forms atria and ventricles.  cardiac muscle tissue, bv and nerves. 3. Endocardium  simple squamous epithelium that lining the inner surface of heart and the heart valves.  Atrial musculature Dense fibrous layer Parietal Areolar tissue pericardium Mesothelium Ventricular musculature Pericardial cavity MYOCARDIUM (cardiac muscle tissue) Mesothelium EPICARDIUM Areolar tissue (visceral pericardium) Connective tissues Areolar tissue ENDOCARDIUM Endothelium 13 STRUCTURE OF HEART – CHAMBERS OF HEART 1. R atrium  receives blood from o superior vena cava (head, neck, upper limbs and chest) o inferior vena cava (the rest of the body) o coronary sinus / cardiac vein  in adult - fossa ovalis  inner wall: o posterior wall and interatrial septum – smooth o anterior wall and inner surface of the auricle – muscular ridges (i.e. pectinate muscles) 14 STRUCTURE OF HEART – CHAMBERS OF HEART 2. R ventricle  R atrioventricular / tricuspid valve o the free edge of each cusp attaches to papillary muscle via chordae tendineae. o closes when R ventricle contracts  Muscular ridges o Trabeculae carneae and moderator band  Pulmonary / semilunar valve 15 STRUCTURE OF HEART – CHAMBERS OF HEART 3. L atrium  Receives blood from o 2 R and L pulmonary vein  Inner wall: o similar to R atrium 4. L ventricle  larger and thicker than R ventricle  L atrioventricular / bicuspid valve o a pair of papillary muscle  Muscular ridges o prominent trabeculae carneae o absent of moderator band  Aortic semilunar valve Transverse section, superior view, atria and vessels removed Frontal section through left atrium and ventricle Pulmonary veins Cardiac Left AV (bicuspid) skeleton valve (open) LEFT ATRIUM LEFT VENTRICLE RIGHT VENTRICLE Left AV (bicuspid) valve (open) Aortic valve (closed) Chordae tendineae (loose) Papillary muscles (relaxed) LEFT Right AV VENTRICLE (tricuspid) (dilated) valve (open) Aortic valve (closed) Pulmonary valve (closed) Relaxed ventricles Right AV Cardiac Left AV (tricuspid) valve skeleton (bicuspid) valve (closed) (closed) Aorta LEFT RIGHT LEFT ATRIUM VENTRICLE VENTRICLE Aortic sinus Left AV (bicuspid) valve (closed) Aortic valve (open) Chordae tendineae (tense) Papillary muscles (contracted) Left ventricle (contracted) Aortic valve (open) Pulmonary valve (open) Contracting ventricles CORONARY CIRCULATION 19 CORONARY CIRCULATION CORONARY ARTERIES: ▸ originate from the base of the ascending aorta. ▸ receive blood from the L ventricle. R CORONARY ARTERIES: ▸ supplies R atrium, portions of both ventricles, portions of the conducting system. ▸ give rise to marginal arteries and posterior interventricular artery. 20 CORONARY CIRCULATION L CORONARY ARTERIES: ▸ supplies L atrium, L ventricle and anterior interventricular septum. ▸ give rise to a circumflex artery and anterior interventricular artery. 21 CORONARY CIRCULATION GREAT CARDIAC VEIN: ▸ drains blood from anterior interventricular artery and branch from L coronary artery. ▸ empties in coronary sinus. OTHER CARDIAC VEINS: ▸ Posterior cardiac vein – drains blood from circumflex artery. ▸ Middle cardiac vein – drains blood from posterior interventricular artery. ▸ Small cardiac vein – drains blood from posterior surface of R atrium and ventricle. ▸ Anterior cardiac veins – drains blood from anterior surface of R ventricle.  Coronary sinus Circumflex artery Great cardiac vein Aortic arch Left coronary Marginal artery artery Posterior Ascending Pulmonary interventricular arch trunk artery Circumflex Posterior Right artery cardiac coronary Anterior vein artery interventricular artery Small Atrial arteries Left cardiac vein Great ventricle cardiac vein Right Anterior coromary cardiac veins artery Small Middle cardiac vein Marginal artery cardiac vein Posterior view Marginal artery Anterior view HISTOLOGY OF HEART & CARDIAC MUSCLE 24 HEART Epicardium Myocardium Endocardium 25 CARDIAC MUSCLE STRUCTURAL FEATURES: ▸ Short, striated, and branched. ▸ Usually one nucleus, centrally located ▸ Less developed sarcoplasmic reticulum and larger T tubule than the skeletal muscle. ▸ Intercalated discs:  Adherens  Desmosomes  Gap junctions ▸ >> large mitochondria and glycogen granules ▸ Injury and repair – death cells are replaced by fibrous c.t. Adherens 27 ORGANIZATION OF CARDIAC MUSCLE FIBER Skeletal muscle Cardiac muscle 28 REVISION