NURS 215 Topic 8 Cardiovascular System PDF

Topic 8: The Cardiovascular and Lymphatic Systems (Circulation) Chapters 18, 19, 20 (parts) in Textbook What is the Cardiovascular System?  Responsible for transporting blood throughout the body  Blood transports oxygen, nutrients, wastes, hormones, etc.  System of blood vesse...

Topic 8: The Cardiovascular and Lymphatic Systems (Circulation) Chapters 18, 19, 20 (parts) in Textbook What is the Cardiovascular System?  Responsible for transporting blood throughout the body  Blood transports oxygen, nutrients, wastes, hormones, etc.  System of blood vessels and a heart  Heart is responsible for moving the blood  Network of blood vessels approx. 100,000 km long Heart Anatomy  Approximately the size of a fist  Right side receives oxygen-poor blood from tissues  Pumps blood to lungs to get rid of CO2, pick up O2, via pulmonary circuit  Left side receives oxygenated blood from lungs  Pumps blood to body tissues via systemic circuit Heart Anatomy  Receiving chambers of heart  Right atrium ▪ Receives blood returning from systemic circuit  Left atrium ▪ Receives blood returning from pulmonary circuit  Pumping chambers of heart  Right ventricle ▪ Pumps blood through pulmonary circuit  Left ventricle ▪ Pumps blood through systemic circuit  Interventricular septum: RV & LV separation Heart Position in the Thoracic Cavity Left of midline Deep to sternum Mediastinum Base Left atrium Superior border Great vessels and SVC Apex (tip of LV) Inferior border  Characteristics of the Pericardium  Pericardium  Encloses the heart  Restricts movement (allows slight amount)  Composed of two parts:  Fibrous pericardium  Serous pericardium ▪ Parietal and visceral (epicardium) layers: pericardial cavity between External Heart Anatomy and Features of the Heart  Atria  Auricles ▪ Muscular extension of atria  Coronary sulcus  Anterior interventricular sulcus External Heart Anatomy and Features of the Heart  Posterior interventric ular sulcus  Between the right and left ventricles Heart Valves  Ensure unidirectional blood flow through heart  Open and close in response to pressure changes  No valves are found between major veins and atria:  Inertia of incoming blood prevents backflow  Heart contractions compress venous openings Heart Valves  Two major types of valves:  Atrioventricular valves located between atria and ventricles  Semilunar valves located between ventricles and major arteries Atrioventricular (AV) Valves  Prevent backflow into atria  Chordae tendineae (attachment)  Papillary muscles  Tricuspid valve (right AV valve): between right atria and ventricle  Mitral valve (left AV valve, bicuspid valve): lies between left atria and ventricle Semilunar (SL) valves  Two semilunar valves prevent backflow from major arteries back into ventricles  Each valve has three cusps  Pulmonary semilunar valve: between right ventricle and pulmonary trunk  Aortic semilunar valve: between left ventricle and aorta Heart Valve Disorders  Incompetent valve: valve does not close tightly  What would be the result of this?  Valvular stenosis: valves become hardened  What would be the result of this?  Defective valves can be replaced by mechanical, animal or cadaver valves Pathway of Blood Through Heart: Right side of the heart  Superior vena cava (SVC), inferior vena cava (IVC), and coronary sinus  Right atrium  Tricuspid valve  Right ventricle  Pulmonary semilunar valve A cardiac cycle Start of one heartbeat to  Pulmonary trunk initiation of the next  Pulmonary arteries Contraction = systole Relaxation = diastole  Lungs Pathway of Blood Through Heart: Left side of the heart  Four pulmonary veins  Left atrium  Mitral valve  Left ventricle  Aortic semilunar valve  Aorta  Systemic circulation Summa ry Vide o: Pathway of Blood Through Heart  Equal volumes of blood are pumped to pulmonary and systemic circuits  Pulmonary circuit is short, low- pressure circulation  Systemic circuit is long, high-friction circulation  Left ventricle walls are 3x thicker than right  Pumps with greater pressure Coronary Circulation  Functional blood supply to heart muscle itself  Delivered when heart is relaxed  Right and left coronary arteries (within coronary sulcus)  Myocardial infarction: results from a blockage in one of these vessels  What is the result of this?  Coronary sinus: deoxygenated blood into right atrium Review Questions  Why is the left ventricular wall thicker than the right?  What are the 2 parts of the serous pericardium?  Freshly oxygenated blood is first received by which part of the heart? Where is deoxygenated blood received?  What are the names and locations of the 4 heart valves? Anatomy of Blood Vessels  The three classes of blood vessels  Arteries, capillaries, and veins  Arteries  Veins  The arteries and veins entering and leaving the heart are great vessels  Blood Vessel Tunics 1. Tunica intima ▪ Endothelium lines lumen 2. Tunica media ▪ Smooth muscle 3. Tunica externa ▪ Connective tissue ▪ Anchor blood vessel to an organ  Larger blood vessels require their own blood supply ▪ Vasa vasorum (tunica externa) Arteries  Three types: 1. Elastic arteries 2. Muscular arteries 3. Arterioles Elastic Arteries  Largest  Near heart:  Eg. Aorta, pulmonary, brachiocephalic, common carotids, subclavians  Elastic fibers  Why?  Branch into muscular arteries Muscular Arteries  Medium-sized  Elastic fibers in two concentric rings between the three tunics: 1. Internal elastic lamina 2. External elastic lamina  Muscular arteries have thicker tunica media Arterioles  Smallest  Less than six cell layers of smooth muscle in tunica media  Sympathetic innervation to tunica media  Causes?  Parasympathetic innervation to tunica media  Causes? Capillaries  Smallest blood vessels  Small diameter  Erythrocyte travel  Wall is only tunica intima  Single layer  Metabolic exchange occurs  What leaves and what enters the capillary blood? Capillary Beds  Some capillary beds fed by a metarteriole:  A thoroughfare channel connects to venule  Function?  Branches from metarteriole = capillaries  Ring of smooth muscle on their walls are true capillaries Capillary Bed Structure  Precapillary sphincters can control blood flow entering bed Types of Capillaries  Continuous: Most common, complete lining  Fenestrated: Contain pores  Fluid exchange  Sinusoids: Large gaps  Cell, large molecule transport  *Where do you think you could find each of these? Veins and Venules  Return blood to heart  Pressure lower  Blood reservoirs Venules  Smallest veins  Companion vessels with arterioles  Smallest are postcapillary venules  Leukocytes may pass through  Venules form veins Veins  Larger than venules  Smaller/medium-sized travel with muscular arteries  Large veins travel with elastic arteries  Most veins contain valves to prevent pooling  Formed from tunica intima  Venous return Questions  What are the 3 different layers of blood vessels?  Do all arteries carry oxygenated blood?  What are 3 different types of capillaries?  How is blood flow to capillary beds controlled? Selected Blood Vessels  We will look at some examples of major blood vessels  *You only need to know the ones we cover in the notes  Naming tips: usually named after body region, organ served or nearby bone  Arteries and veins often side by side https://newatlas.com/blood-vessel-regrowth-u- texas/21520/  Not all vessels same on right and left sides Major Arteries of the Upper Trunk/ Head Regions  Aorta: ascending and abdominal (descending)  Branching from ascending aorta:  Brachiocephalic trunk: branches into subclavian(right) and common carotid (right)  Common carotid (left)  Subclavian (left)  *Purpose of these arteries ? Major Arteries of the Upper limb  Subclavian becomes axillary artery  Brachial artery  Radialand ulnar arteries Major Arteries of the Lower Trunk/ Limbs Regions  Abdominal aorta branches into many arteries, supplying several abdominal organs (e.g. renal arteries)  Also continues to lower limbs  Common iliac artery  External iliac artery  Femoral artery  Popliteal artery, branches into anterior and posterior tibial arteries Major Selected Veins of the Upper Trunk/ Head  Veins of head primarily drain into internal and external jugular veins  Veins of upper limbs drain into subclavian veins  These drain into right and left brachiocephalic veins  Merging into the superior vena cava, into the right atrium Major Selected Veins of the Lower Trunk/ Limbs  Blood from lower limbs eventually drain into great saphenous and femoral veins  Common iliac vein  Inferior vena cava (other veins from abdominal organs also drain into here, e.g. renal veins)  Drains into right atrium Questions  Please trace the pathway of blood from the heart to the hand, listing the major arteries along the way  Which veins bring blood back from the lower limbs to the inferior vena cava?  Ifthere was a blockage of the brachiocephalic trunk, which major areas of the body would be affected? The Lymphatic System Introduction (Ch 20)  Returns fluid which leaks out of blood vessels, includes:  Lymph: fluid, approx. 3L circulates per day  Lymphatics: a network of vessels  Lymph nodes: cleanse lymph, contain immune cells  Spleen, thymus, tonsils, other tissues also included Lymphatics: Lymphatic Capillaries  Highly-permeable, blind-ended vessels, weave between blood capillaries and tissue cells  Absent in bone, tooth tissues  Loosely overlapping endothelial cells form minivalves  Minivalves anchored to connective tissue, will open more with more fluid  Specialized lymphatic capillaries in intestine are called lacteals (help absorb fat) Lymphatics: Larger Lymphatic Vessels  Similar structure to veins, more valves  Lymph capillaries drain into larger collecting lymphatic vessels  Lymph drains into larger lymphatic trunks  Finally, drains one of 2 lymphatic ducts Lymphatics: The Lymphatic Ducts  2 Lymphatics ducts:  Right lymphatic duct: drains right upper limb, right side of head and thorax into junction of right internal jugular and subclavian veins  Thoracic duct: drains rest of body into junction of left internal jugular and subclavian veins  Lymphoid Organs  Lymphoid organ tissue mainly comprised of reticular connective tissue  Mainly functions to house and allow for lymphocyte development  2 main types of lymphoid organs:  Primary lymphoid organs: red bone marrow and thymus ▪ Allow for T and B cell maturation  Secondary lymphoid organs: includes lymph nodes, spleen, mucosa- associated lymphoid tissue (MALT) ▪ Where mature lymphocytes become activated (by antigens) Lymphoid Organs: Spleen  Served by splenic artery and vein, enter through hilum  White pulp: site of lymphocyte storage/ proliferation  Red pulp: old red blood cells and pathogens are broken down  Contains macrophages to engulf these Lymphatic Organs: Lymph Nodes  Hundreds throughout body (deep and near surface):  Common body surface regions: cervical, axillary and inguinal  Functions:  Cleansing lymph by removing debris, organisms using macrophages  Area for lymphocyte activation Lymphatic Organs: Lymph Node Structure  Surrounded by fibrous capsule  Capsule extends inward into trabeculae, to divide node  2 regions: outer cortex and inner medulla  Lymph enters through afferent lymphatics vessels  Travels through several sinuses  Lymph exits from efferent lymphatic vessels Lymphatic Organs: Thymus  Bi-lobed organ inferior to neck  T-cells mature (more in 230), most active in childhood  Immature T-cells kept from blood through blood-thymus barrier  Primarily epithelial cells instead of reticular connective tissue  Cortex: outer area, most lymphocytes  Medulla: inner area, fewer lymphocytes  Site of special “regulatory t-cells”, which prevent autoimmunity Lymphatic Organs: MALT  MALT: mucosa-associated lymphoid tissue  Protects body from pathogens entering though mucosal barrier  Includes:  Tonsils: around pharynx (more in respiratory)  Peyer’s patches: small clusters within small intestine  Appendix: offshoot of large intestine Questions  Pleasedescribe the pathway of lymphatic flow from a tissue, into the heart  What is meant by MALT? What role does this type of tissue play?  Whydo you think lymph nodes under your arms sometimes swell after a vaccine?