BSC 2086 1st Edition Lecture 9 Outline of Last Lecture I Blood Typing Continued II White Blood Cells III Platelets IV Hemostasis Outline of Current Lecture I Hemostasis Continued II Introduction to Cardiovascular System III Anatomy of the Heart Current Lecture I Hemostasis Continued a Coagulation Pathways i Extrinsic Pathway 1 Clots faster than intrinsic pathway 2 Starts at vessel wall located outside of bloodstream 3 Tissue factor TF released by damaged cells a The more the damage the more TF released b Enzyme complex TF Ca2 other compounds 4 Activates Factor X ii Intrinsic Pathway 1 Begins inside bloodstream with circulating proenzymes 2 Enzymes activated by collagen a Collagen only exposed to blood when vessel is damaged 3 Platelets release factors such as PF 3 4 Factor X activated by series of reactions iii Common Pathway 1 Intrinsic and extrinsic paths converge 2 Enzyme prothrombinase is made from activated Factor X a Prothrombin is converted to thrombin b Thrombin transforms fibrinogen to fibrin b Feedback Control of Blood Clotting i Thrombin 1 Stimulates TF formation II 2 Stimulates PF 3 release a Makes a positive feedback loop b Accelerates clotting c Restriction of Blood Clotting i Anticoagulants inhibits clotting ii Heparin made by basophils and mast cells to prevent clotting iii Aspirin stops production of prostaglandins and thromboxane A2 production reduces platelets accumulation iv Protein C activated by thrombomodulin 1 Stops clotting factors 2 Stimulates plasmin enzyme to break down fibrin v Prostacyclin stops platelet accumulation opposed ADP and thrombin d Calcium Ions and Vitamin K i Both essential to clotting process ii Vitamin K needed for clotting factors including prothrombin iii Diets low in fat vitamin K or using antibiotics to kill bacteria that produce vitamin K can lead to deactivation of clotting system e Clot Restriction i Pulls broken parts of vessel together 1 Reduces bleeding and stabilizes injury site ii Reduces size of damaged area 1 Make it easier for fibrocytes smooth muscle cells and endothelial cells to finish repairs f Fibrinolysis i Slows process of clot dissolving 1 Thrombin and tissue plasminogen activator t PA 2 Activate plasminogen ii Plasminogen makes plasmin which digests fibrin strands Introduction to Cardiovascular System a Circuits i Pulmonary circuit 1 Performed by right side of heart 2 Carries blood to and from lungs ii Systemic circuit 1 Performed by left side of the heart 2 Carried blood to and from body b Four chambers of the heart i Left atrium gets blood from the pulmonary circuit ii Left ventricle pumps blood to systemic circuit iii Right atrium gets blood from systemic circuit iv Right ventricle pumps blood to pulmonary circuit c Blood vessel types i Arteries 1 Carry blood away from heart III 2 Mostly carry oxygenated blood ii Veins 1 Carry blood to heart 2 Mostly carry deoxygenated blood iii Capillaries 1 Network of vessels between arteries and veins 2 Aka Exchange vessels 3 Dissolved gases nutrients and wastes are exchanged here between blood and tissue iv Anatomy of the Heart a Structure i Involuntary muscle pump ii Thoracic cavity iii Apex pointed tip points to left side of the body iv Great veins and arteries located towards the top base v Pericardial sac surrounds it vi Sits in region between 2 pleural cavities known as mediastinum b Pericardium i Double lining of pericardial cavity ii Layers 1 Visceral pericardium inner layer 2 Parietal pericardium outer layer a Forms inner layer of pericardial sac b Surrounds and stabilizes heart 3 Pericardial cavity between the partietal and visceral layers a Contains pericardial fluid which lubricates and prevents friction b Pericarditis infection of pericardium causing inflammation c Superficial anatomy i Atria upper chambers thin walled ii Sulci grooves wall that separates chamber 1 Coronary sulcus between atria and ventricles 2 Interventricular sulcus between left and right ventricles a Has blood vessels of cardiac muscle d Heart wall i Epicardium outer layer 1 Visceral pericardium that covers the heart ii Myocardium middle layer 1 Muscular wall of heart 2 Has concentric layers of cardiac muscle tissue 3 Atrial myocardium wraps around great vessels 4 2 divisions of ventricular myocardium iii Endocardium inner layer 1 Prevents exchange of nutrients and wastes as blood is flowing through heart e Cardiac Muscle tissue i Involuntary muscle ii Connected by intercalated discs 1 Desmosomes tightly links cells together a Bear force of contraction 2 Gap junctions links cytoplasms of cells a Propagate action potentials iii Cardiac muscle cells 1 Small 2 Single nucleus 3 Intercalated discs 4 Branching interconnections between cells f Internal anatomy i Interatrial septum divides atria ii Interventricular septum divides ventricles iii Atrioventricular AV valves fibrous tissue folds that extend into openings between atria and ventricles 1 Connect right atria to right ventricle and left atrium to left ventricle 2 Allow blood to flow from atria to ventricles in one direction only g Right atrium i Superior vena cava gets blood from head neck upper limbs and chest ii Inferior vena cava gets blood from trunk viscera and lower limbs iii Coronary sinus opens into right atrium returns the blood from the cardiac veins iv Foramen ovale opening found before birth in interatrial septum 1 Connect both atria 2 Forms the fossa ovalis after birth once it closes h Right ventricle i Edges attach to chordae tendineae by papillary muscles of ventricle 1 They prevent the AV valves from opening backwards by tensing before the ventricle contracts ii Right atrioventricular AV valve 1 Aka Tricuspid valve 2 Has 3 cusps 3 Prevents backflow of blood 4 Allows blood to go from right atrium to right ventricle i Pulmonary circuit i Right ventricle pushes blood through the pulmonary semilunar valve to the pulmonary trunk j k l m n o ii Pulmonary trunk divides into left and right pulmonary arteries which leads to left and right lungs Left atrium i Left and right pulmonary veins get blood from the lungs and deliver it to left atrium ii Blood goes into left ventricle through the left atrioventricular valve 1 Aka Bicuspid or mitral valve Left Ventricle i Holds same amount as right ventricle ii Larger muscle is thicker and more powerful because it needs to push blood to entire body 1 High amount of pressure and force needed to push blood through aorta Systemic circulation i Blood leaves the right ventricle through the aortic
View Full Document
Unlocking...