BSC 2086 1st Edition Lecture 9 Outline of Last Lecture I. Blood Typing Continued II. White Blood Cells III. PlateletsIV. Hemostasis Outline of Current Lecture I. Hemostasis ContinuedII. Introduction to Cardiovascular SystemIII. Anatomy of the Heart Current LectureI. Hemostasis Continued a. Coagulation Pathways i. Extrinsic Pathway 1. Clots faster than intrinsic pathway2. Starts at vessel wall located outside of bloodstream3. Tissue factor (TF) released by damaged cells a. The more the damage the more TF releasedb. Enzyme complex = TF + Ca2++ other compounds4. Activates Factor Xii. Intrinsic Pathway1. Begins inside bloodstream with circulating proenzymes 2. Enzymes activated by collagen a. Collagen only exposed to blood when vessel is damaged3. Platelets release factors such as PF-3 4. Factor X activated by series of reactions iii. Common Pathway1. Intrinsic and extrinsic paths converge2. Enzyme prothrombinase is made from activated Factor X a. Prothrombin is converted to thrombinb. Thrombin transforms fibrinogen to fibrin b. Feedback Control of Blood Clotting i. Thrombin: 1. Stimulates TF formation2. Stimulates PF-3 releasea. 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 clottingiii. Aspirin – stops production of prostaglandins and thromboxane A2 production, reduces platelets accumulation iv. Protein C – activated by thrombomodulin 1. Stops clotting factors2. Stimulates plasmin enzyme to break down fibrinv. Prostacyclin – stops platelet accumulation, opposed ADP and thrombin d. Calcium Ions and Vitamin Ki. Both essential to clotting processii. Vitamin K needed for clotting factors including prothrombiniii. Diets low in fat, vitamin K or using antibiotics to kill bacteria that produce vitamin K can lead to deactivation of clotting systeme. Clot Restrictioni. Pulls broken parts of vessel together1. Reduces bleeding and stabilizes injury siteii. Reduces size of damaged area1. Make it easier for fibrocytes, smooth muscle cells and endothelial cells to finish repairs f. Fibrinolysis i. Slows process of clot dissolving1. Thrombin and tissue plasminogen activator (t-PA)2. Activate plasminogenii. Plasminogen makes plasmin which digests fibrin strands II. Introduction to Cardiovascular System a. Circuitsi. Pulmonary circuit 1. Performed by right side of heart2. Carries blood to and from lungsii. Systemic circuit1. Performed by left side of the heart 2. Carried blood to and from body b. Four chambers of the hearti. Left atrium: gets blood from the pulmonary circuitii. Left ventricle: pumps blood to systemic circuitiii. 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 heart2. Mostly carry oxygenated bloodii. Veins 1. Carry blood to heart2. Mostly carry deoxygenated bloodiii. 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.III. Anatomy of the Hearta. Structurei. Involuntary muscle pumpii. Thoracic cavityiii. Apex (pointed tip) points to left side of the bodyiv. Great veins and arteries located towards the top (base) v. Pericardial sac surrounds itvi. Sits in region between 2 pleural cavities known as mediastinum b. Pericardium i. Double lining of pericardial cavityii. Layers:1. Visceral pericardium: inner layer2. Parietal pericardium: outer layera. Forms inner layer of pericardial sacb. Surrounds and stabilizes heart3. Pericardial cavity – between the partietal and visceral layers a. Contains pericardial fluid which lubricates and prevents frictionb. Pericarditis – infection of pericardium causing inflammation c. Superficial anatomyi. Atria: upper chambers; thin walledii. Sulci: grooves wall that separates chamber 1. Coronary sulcus- between atria and ventricles2. Interventricular sulcus: between left and right ventricles a. Has blood vessels of cardiac muscle d. Heart walli. Epicardium – outer layer1. Visceral pericardium that covers the heartii. Myocardium – middle layer 1. Muscular wall of heart2. Has concentric layers of cardiac muscle tissue 3. Atrial myocardium wraps around great vessels4. 2 divisions of ventricular myocardiumiii. Endocardium – inner layer 1. Prevents exchange of nutrients and wastes as blood is flowing through heart e. Cardiac Muscle tissuei. Involuntary muscleii. Connected by intercalated discs 1. Desmosomes – tightly links cells togethera. Bear force of contraction 2. Gap junctions – links cytoplasms of cells a. Propagate action potentials iii. Cardiac muscle cells1. Small2. Single nucleus3. Intercalated discs4. Branching interconnections between cells f. Internal anatomy i. Interatrial septum: divides atriaii. Interventricular septum: divides ventriclesiii. 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 ventricle2. Allow blood to flow from atria to ventricles in one direction only g. Right atriumi. 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 ventriclei. 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) valve1. Aka. Tricuspid valve 2. Has 3 cusps3. Prevents backflow of blood4. Allows blood to go from right atrium to right ventricle i. Pulmonary circuiti. Right ventricle pushes blood through the pulmonary semilunar valve to the pulmonary trunkii. Pulmonary trunk divides into left and right pulmonary arteries which leads to left and right lungs j. Left atrium i. Left and right pulmonary veins get blood from the lungs and deliver it to left atriumii. Blood goes into left ventricle through the left atrioventricular valve1. Aka. Bicuspid or mitral valve k. Left Ventricle i. Holds same amount as right ventricle ii. Larger, muscle is thicker and more powerful because it needs to
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