THE CIRCULATORY SYSTEM NOTES.pdf

THE CIRCULATORY SYSTEM By Ms. Julie-Marie V. Labajo, RMT, MLS (ASCPi) ✓ Functions: o o o Carries oxygen and food to the cells of the body and carries carbon dioxide and other wastes away from the cells. Coagulation process Defends body against disease ✓ Regulation of body’s temperature ✓ Two main co...

THE CIRCULATORY SYSTEM By Ms. Julie-Marie V. Labajo, RMT, MLS (ASCPi) ✓ Functions: o o o Carries oxygen and food to the cells of the body and carries carbon dioxide and other wastes away from the cells. Coagulation process Defends body against disease ✓ Regulation of body’s temperature ✓ Two main components: 1. Cardiovascular System 2. Lymphatic System I. HEART STRUCTURE ✓ Four chambered, hollow, muscular organ ✓ Surrounded by PERICARDIUM ✓ LAYERS of the heart: 1. Epicardium 2. Myocardium 3. Endocardium 1 ✓ CHAMBERS of the heart: 1. Atria - upper chambers; receiving 2. Ventricles - lower chambers; delivering ✓ VALVES of the heart: 1. Atrioventricular valves - entrance to the ventricles 2. Semilunar valves - exit the ventricles ✓ SEPTA of the heart 1. Interatrial septum - partition that separates the right and left atria 2. Interventricular septum - partition that separates the right and left ventricles 2 ❖ CORONARY CIRCULATION The heart receives its blood supply via the right and left coronary (also called cardiac arteries). Coronary (cardiac) veins return oxygen poor blood from the heart muscle back to the heart. II. HEART FUNCTION ✓ CARDIAC CYCLE One complete contraction and subsequent relaxation of the heart. The contracting phase of the cardiac cycle is called systole, and the relaxing phase is called diastole. ✓ ELECTRICAL CONDUCTION SYSTEM To be effective at pumping blood, the heart’s contractions must be synchronized and is achieved by means of specialized muscle cells that form the electrical conduction system. Initiated by an electrical impulse generated from the Sinoatrial Node/SA node (pacemaker) ✓ ELECTROCARDIOGRAM A graphic record of the heart’s electrical activity during the cardiac cycle produced by an electrograph. The P wave of the tracing represents the activity of the atria and is usually the first wave seen. The QRS complex (a collection of three waves), along with the T wave, represents the activity of the ventricles. ✓ HEART RATE AND CARDIAC OUTPUT The heart rate is the number of heart beats per minute. The normal adult heart rate averages 72 beats per minute. The volume of blood pumped by the heart in 1 minute is called the cardiac output and averages 5 liters per min. ❖ ❖ ❖ ❖ ARRHYTHMIA - an irregularity in the heart’s rate, rhythm, or beat BRADYCARDIA - a slow rate, less than 60 beats per minute TACHYCARDIA - a fast rate, over 100 beats per minute EXTRASYSTOLE - extra beats before the normal beat ✓ PULSE Palpable rhythmic throbbing caused by the alternating expansion and contraction of an artery as a wave of blood passes through it. ✓ BLOOD PRESSURE 3 Force (pressure) or tension exerted by the blood on the walls of blood vessels. Measured using a sphygmomanometer. Expressed in millimeters of mercury (mm Hg). TWO COMPONENTS: ❖ Systolic pressure: the pressure in the arteries during contraction of the ventricles ❖ Diastolic pressure: the arterial pressure during relaxation of the ventricles III. HEART DISORDER o o o o o o o IV. Angina pectoris (also called ischemic heart disease (IHD): pain on exertion caused by inadequate blood flow to the myocardium from the coronary arteries. Aortic stenosis: narrowing of the aorta or its opening. Bacterial endocarditis: an infection of the lining of the heart, most caused by streptococci. Congestive heart failure (CHF): impaired circulation due to inadequate pumping of a diseased heart, resulting in fluid buildup (edema) in the lungs or other tissues. Myocardial infarction (MI): heart attack or death of heart muscle due to obstruction (occlusion) of a coronary artery Myocardial ischemia: insufficient blood flow to meet the needs of the heart muscle. Pericarditis: inflammation of the pericardium HEART DIAGNOSTIC TESTS o o o o o o o o o o o o o Arterial blood gases (ABGs) Aspartate aminotransferase (AST) or serum glutamic–oxaloacetic transaminase (SGOT) Cholesterol Creatine kinase (CK) Creatine kinase (CK)-MB Digoxin Electrocardiogram (ECG or EKG) Lactate dehydrogenase (LD) isoenzymes Microbial cultures Myoglobin Potassium (K) Triglycerides Troponin T (TnT) 4 V. VASCULAR SYSTEM ✓ TWO DIVISIONS: A. PULMONARY CIRCULATION - carries blood from the heart to the lungs to remove carbon dioxide and pick up oxygen B. SYSTEMIC CIRCULATION - carries blood and nutrients from heart to the body cells ❖ ARTERIES - blood vessels that carry blood away from the heart - carry oxygenated (oxygen-rich) blood - normal systemic arterial blood is bright red * The pulmonary artery is the only artery that carries deoxygenated, or oxygen-poor blood. It carries deoxygenated blood from the heart to the lungs. ❖ VEINS - blood vessels that return blood to the heart - carry blood that is low in oxygen (deoxygenated or oxygen-poor) - venous blood is dark red * The pulmonary vein is the only vein that carries oxygenated, or oxygen-rich blood. It carries deoxygenated blood from the lungs back to the heart. ❖ ❖ ❖ ❖ ❖ ARTERIOLES - smallest branches of arteries that join with the capillaries. AORTA - largest artery in the body VENULES - smallest veins at the junction of the capillaries VENAE CAVAE - largest veins in the body GREAT SAPHENOUS VEIN - longest veins in the body ❖ CAPILLARIES - microscopic, one-cell-thick vessels that connect the arterioles and venules, forming a bridge between the arterial and venous circulation. - allows the exchange of oxygen for carbon dioxide and nutrients for wastes between the cells and the blood. 5 VI. BLOOD VESSEL STRUCTURE ✓ LAYERS: o o o TUNA ADVENTITIA - outer layer TUNA MEDIA - middle layer TUNA INTIMA - inner layer or lining of a blood vessel. ✓ LUMEN - internal space of a blood vessel ✓ VALVES - as blood is moved forward by the movement of skeletal muscle, the valves help keep it flowing toward the heart by allowing blood to flow in only one direction. VII. PHLEBOTOMY-RELATED VASCULAR ANATOMY ✓ ANTECUBITAL FOSSA - Shallow depression in the arm that is anterior to (in front of) and below the bend of the elbow. - Where antecubital veins are found. ❖ ANTECUBITAL VEINS - can be “H” shaped or “M” shaped 1. “H” SHAPE MEDIAN CUBITAL VEIN - 1ST CHOICE CEPHALIC VEIN - 2ND CHOICE BASILIC VEIN - 3RD CHOICE 2. “M” SHAPE Median vein (also called the intermediate antebrachial vein) Median cephalic vein (also called the intermediate cephalic vein) Median basilic vein (also called the intermediate basilic vein) ✓ Other site for Venipuncture: o o o Other arm and hand veins Leg, Ankle, and Foot Veins Arteries - not used for routine blood collection! 6 VIII. VASCULAR SYSTEM DISORDERS o o o o o o o o o o o IX. TESTS FOR VASCULAR SYSTEM DISORDERS o o o o o o X. ✓ ✓ ✓ ✓ Aneurysm: a localized dilation or bulging in the wall of a blood vessel, usually an artery Arteriosclerosis: thickening, hardening, and loss of elasticity of artery walls Atherosclerosis: a form of arteriosclerosis involving thickening of the intima of the artery due the buildup of plaque (lipid–calcium deposits) Disseminated intravascular coagulation (DIC): pathological widespread clotting and fibrinolysis in which coagulation factors are consumed to such an extent that bleeding occurs. Embolism: obstruction of a blood vessel by an embolus. Embolus: a blood clot, part of a blood clot, or other mass of undissolved matter Hemorrhoids: varicose veins in the rectal area Phlebitis: inflammation of a vein Thrombophlebitis: inflammation of a vein along with thrombus (blood clot) formation Thrombus: a blood clot in a blood vessel or organ Varicose veins (varices): swollen, knotted superficial veins. D-Dimer Fibrin degradation products (FDP) Lipoproteins Prothrombin time (PT) Partial thromboplastin time (PTT/APTT) Triglycerides THE BLOOD a pH of about 7.4 a mixture of fluid and cells the fluid portion of the blood is called plasma (55%) the cellular portion is referred to as the formed elements (45%) 1. PLASMA (55%) is a clear, pale-yellow fluid that is nearly 90% water (H2O) and 10% solutes (dissolved substances). Solutes composed of gases, minerals, nutrients, proteins (albumin), waste products, vitamins, hormones, drugs. 2. FORMED ELEMENTS (45%) Composed of: ✓ ERYTHROCYTES or RBCs ✓ LEUKOCYTES or WBCs - Agranulocytes - Granulocytes 7 ✓ THROMBOCYTES or PLATELETS A. ERYTHOCYTES or RBCs - Most numerous cells in the blood, averaging 4.5 to 5 million per cubic millimeter of blood - MAIN COMPONENT: Hemoglobin - MAIN FUNCTIONS: 1. Carry oxygen from the lungs to the cells 2. Carry carbon dioxide from the cells back to the lungs - Produced in the BONE MARROW - Mature RBCs have a life span of approximately 120 days - Described as anuclear (having no nuclei) and biconcave (indented from both sides) disks B. LEUKOCYTES or WBCs - Produced in the BONE MARROW and LYMPHATIC TISSUE - MAIN FUNCTION: neutralize or destroys pathogens (phagocytosis) - TWO TYPES: ✓ Agranulocytes ✓ Granulocytes ❖ GRANULOCYTES - WBCs containing easily visible granules - NEUTROPHILS, EOSINOPHILS, BASOPHILS C. THROMBOCYTES - also known as PLATELETS - smallest formed element that is just a fragment of megakaryocyte - average adult ranges from 150,000 to 450,000 per cubic millimeter - essential for COAGULATION 8 WBC TYPE GRANULOCYTES NEUTROPHILS EOSINOPHILS BASOPHILS AGRANULOCYTES MONOCYTES LYMPHOCYTES Average Percentage of WBCs Total (Adults) 65% Up to 3% Less than 1% Description/Staining characteristics Most numerous types of WBC. Segmented or multilobed nucleus. Fine-textured lavender staining granules Beadlike granules that stain bright orange– red. Two-lobed nucleus Least numerous type of WBC: Large dark blue–back staining granules that often obscure a typically S-shaped nucleus. Function Lifespan Destroy pathogens by phagocytosis 6 hours to a few days Ingest and detoxify foreign protein; help turn off immune reactions; increase with allergies and pinworm infestations. Release histamine and heparin, which enhance the inflammatory response. 8–12 days Thought to live several days 1%–7% Largest WBC; fi ne, gray– blue cytoplasm and a large, dark-staining nucleus Destroy pathogens by phagocytosis; first line of defense in the inflammatory process. Several months 15%–30% Second most numerous type of WBC; typically has a large, round, dark-purple nucleus that occupies most of the cell and is surrounded by a thin rim of pale-blue cytoplasm T lymphocytes directly attack infected cells; B lymphocytes rise to plasma cells that produce immunoglobulins (antibodies) that are released into the bloodstream to circulate and attack foreign cells Varies from a few hours to a number of years 9 XI. BLOOD TYPE ✓ An individual’s blood type (also called blood group) is inherited and is determined by the presence or absence of certain proteins called antigens on the surface of the red blood cells. ✓ Two blood group systems: o o ABO system Rh Factor system ❖ ABO blood group system FOUR BLOOD TYPES: A, B, AB, O ▪ ▪ ▪ ▪ TYPE A - has the A antigen; has anti-B antibody TYPE B - has the B antigen; has anti-A antibody TYPE AB - has both the A and B antigens; neither anti-A nor anti-B antibody TYPE O - has neither A nor B antigens; has BOTH anti-A and anti-B antibody * TYPE O is the MOST COMMON blood type; UNIVERSAL DONOR * TYPE AB is the LEAST COMMON blood type; UNIVERSAL RECIPIENT ❖ RH blood group system Based upon the presence or absence of an RBC antigen called the D antigen, also known as Rh factor. Individuals who are Rh negative can only produce Rh antibodies (sensitized) once they are exposed to and Rh-positive blood. *HEMOLYTIC DISEASE OF THE NEWBORN or HDN Destruction of the RBCs of a subsequent Rh-positive fetus because Rh antibodies produced by the mother (Rh negative mother who was once sensitized and produced Rh antibodies) can cross the placenta into the fetal circulation. COMPATIBILITY OR CROSSMATCHING A test to determine if the donor unit of blood and the blood of the patient recipient are compatible (suitable to be mixed together). 10 XII. BLOOD SPECIMENS ✓ SERUM ✓ PLASMA ✓ WHOLE BLOOD ❖ SERUM - Remaining fluid portion after the blood has been clot (clotted specimen). - Can be separated from the clot by centrifugation. - Normal fasting serum is clear, pale-yellow fluid. - Serum has the same composition as plasma EXCEPT that it does not contain fibrinogen, because the fibrinogen was used in the formation of the clot. ❖ PLASMA - Fluid portion of a centrifuged anticoagulated whole blood specimen. - Normal fasting plasma is a clear to slightly hazy pale-yellow fluid. - The major difference between plasma and serum is that plasma contains fibrinogen. ❖ WHOLE BLOOD - Tests like glycohemoglobin or HBA1C is performed using whole blood since it cannot be performed with using serum or plasma. - To obtain whole blood, the tube must contain an anticoagulant. XIII. BLOOD DISORDERS o o o o o o o XIV. Anemia: an abnormal reduction in the number of RBCs in the circulating blood Leukemia: disorder involving the multiplication of immature forms of WBCs in the blood Leukocytosis: an abnormal increase in WBCs in the circulating blood Leukopenia: an abnormal decrease in WBCs Polycythemia: an abnormal increase in RBCs Thrombocytosis: increased number of platelets Thrombocytopenia: decreased number of platelets BLOOD DIAGNOSTIC TESTS o o o o o o o o o ABO and Rh type Bone marrow examination Complete Blood Count (CBC) Crossmatch Differential (diff) Count Erythrocyte Sedimentation Rate (ESR) Ferritin Hematocrit (Hct) Hemoglobin (Hb or Hgb) 11 o o o o o XV. Hemogram Indices (MCH, MCV, MCHC) Iron (Fe) Reticulocyte (retic) Count Total iron-binding Capacity (TIBC) HEMOSTASIS AND COAGULATION - Hemostasis is the arrest or stoppage of bleeding. Requires the endothelial cells, platelets, plasma, proteins, and the coagulation process. When a blood vessel is injured, it begins to repair the damage involving FOUR interrelated responses: (a) Vasoconstriction (b) Formation of a primary platelet plug in the injured area (c) Secondary Hemostatic plug (d) Fibrinolysis A. VASOCONSTRICTION - A reduction in the diameter of the blood vessel caused by contraction of smooth muscle fibers in the tunica media. B. FORMATION OF A PRIMARY PLATELET PLUG Occurs during the initiation phase of the coagulation process. It involves the adhesion, activation, and aggregation of platelets. C. SECONDARY HEMOSTATIC PLUG - For injuries with more tissue damage, the stimulus for coagulation is strong, and the coagulation process continues. - Involves the amplification and propagation phases of the coagulation. D. FIBRINOLYSIS - The process by which fibrin is dissolved. 12 XVI. HEMOSTATIC DISORDERS o Deep venous thrombosis (DVT): a blood clot that forms in a large vein in the leg. o Disseminated intravascular coagulation (DIC): pathological, widespread clotting and fibrinolysis at the same time, in which coagulation factors are consumed to such an extent that bleeding occurs. o Hemophilia: a hereditary condition characterized by bleeding due to increased coagulation time. The common type of hemophilia is due to factor VIII deficiency along with factor IX (Christmas factor). o Thrombocytopenia: an abnormal decrease in platelets. XVII. TESTS OF HEMOSTATIC PROCESS o o o o o o o Bleeding time (BT) D-dimer Factor assays Fibrin degradation products (FDP) Platelet function assay (PFA) Prothrombin time (PT) Partial thromboplastin time (PTT or APTT) XVIII. THE LYMPHATIC SYSTEM - FUNCTIONS: ✓ Returns tissue fluid to the bloodstream, ✓ Protects the body by removing microorganisms and impurities processes lymphocytes, ✓ Delivers fats absorbed from the small intestine to the bloodstream. ✓ Lymphoid tissue, of which nodes are composed, is a special kind of tissue with the ability to remove impurities and process lymphocytes. ✓ Lymph nodes are able to trap and destroy bacteria and foreign matter and produce lymphocytes. ✓ Tonsils, thymus, gastrointestinal tract, and spleen 13