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CARDIOVASCULAR SYSTEM Blood pressure Hypotension Hypertension Factors that effect BP Cardiac output ASHSD Blood volume Shock: Hypovolemic Vascular Cardiogenic Terminology Palpitations Flutters Chest pain Shortness of breath (SOB) Intermittent claudication ECG/EKG Echocardiogram Doppler Arteriography Cardiovascular System Chapter 18/19 Physiology Closed circulatory system of vessels powered by a pump – the heart Works from in-utero to death Flow and pressure of blood changes due to environmental needs 8-10 pints of blood in most adults Heart location Mediastinum of the thorax Behind the sternum Front of vertebral column Between the 2nd to 6th ribs Tilted slightly to the left – 2/3 mass Posteriorly, rests against 5th – 8th vertebra Apex on diaphragm – 5th-6th ribs + L clavicle Upper border – below 2nd rib Size and shape Size of fist By age 25, heart reaches mature form – M – 310 g an F 225g Tall, thin individuals have elongated heart Short, stocky individuals have wider heart 4 ¾” length – 3 ½” wide – 2 ½” deep Coverings Pericardium – two parts – fibrous / serous epicardium which attaches to blood vessels emerging from the top of the heart Sac – fibrous tissue lined with serous membrane Pericardial space – lubricating fluid – pericardial fluid to reduce friction Layers summarized pg 557 Layers Epicardium/pericardium Parietal layer fibrous outer covering Visceral layer– serous membrane attached to the myocardium Myocardium Endocardium, Epicardium Surrounds the heart Protection Reduction of friction Myocardium Major portion/mass Cardiac muscle cells exclusively found in the heart These cells can pass action potential between each other which assists with electrical movement to produce contraction Autorhythmic – contract on their own in an alternating contraction /relaxation cycle Pump to move blood Endocardium Inner most lining Endothelium Very smooth Reduces the possibility of RBC destruction Chambers Four Atria/atrium – receiving chambers from veins Foramen ovale – passageway between the 2 atria so that the lungs are bypassed in the fetus Fossa ovale – scar tissue where foramen ovale existed until closed within 6-9 mo. After birth Ventricles/ventricle – pumping chambers Valves Four Atrioventricular Tricuspid Bicuspid /mitral Semilunar Pulmonary Aortic What is the purpose of the chordae tendineae? Anchors the mitral and tricuspid valves to the small papillary muscles of the ventricles Types of blood vessels Artery – carries blood away from the heart and normally carries oxygenated blood Vein – carries blood toward the heart and normally carries deoxygenated blood arterioles venules Capillary – gas exchange occurs Layers Three layers Tunica adventitia: outer layer of tough fibrous tissue Tunica media: smooth muscle which allows vessels to constrict/dilate Tunica intima: smooth, inner elastic layer (lumen = internal diameter) Arteries Carry blood AWAY from the heart All BUT pulmonary arteries carry oxygenated blood Aorta: largest artery; 1 inch in diameter Arterioles: smallest arteries Coronary arteries: most important; supply blood to the heart muscle Left and right main coronary artery Left coronary artery - left anterior descending - left circumflex branch Right coronary artery - right atrium and right ventricle Veins Carry blood TOWARD the heart All BUT pulmonary veins carry deoxygenated blood Layers much thinner, less elastic Series of internal valves that work against the flow of gravity to prevent reflux Superior and inferior vena cava: largest veins Venules: smallest veins Capillaries Tiny, microscopic vessels Walls one cell layer thick Function: to transport and diffuse essential materials to and from the body’s cells and the blood Blood supply 5 coronary arteries Heart and blood vessel disease #1 cause of death in U.S. – Texas is a leader! Incapacitation occurs Arteriosclerosis Atherosclerosis Read bullets pg 564 Myocardial infarction causes ischemia – death What is the meaning of anastomosis? Detour around diseased or clotted areas Tracing a drop of blood through the body Superior and inferior vena cava Right atrium Tricuspid valve Right ventricle Pulmonary semilunar valve Pulmonary arteries Lungs ( O2 and CO2 exchange = external respiration) Pulmonary veins Left atrium Bicuspid/Mitral valve Left ventricle Aortic semilunar valve Aorta - all parts of body via arteries Arterioles Capillaries of individual tissues (O2 and CO2 exchange = internal respiration) Venules Veins Superior and inferior vena cava Conduction circuits of the heart Pulmonary circuit: transport of blood from the right side of the heart to the lungs and then back to the left side of the heart Systemic circuit: transport of blood from the left side of the heart to all parts of the body and then back to the right side of the heart Coronary circuit: transport blood from the left side of the heart to the heart tissues and back to the right side of the heart Conductivity Enables heart to contract rhythmically and continuously without motor nerve impulses Arrhythmia: myocardial cells leak sodium faster than the SA node - irregular heart beat SA (sinoatrial) node: pacemaker located where the superior and inferior vena cava enter the right atrium AV (atrioventricular) node: sends impulses to ventricles Bundle of His/bundle branches: in septum Purkinje fibers: in heart wall to distribute nerve impulses Cardiac cycle One (1) contraction (systole = 0.3 seconds) + one (1) relaxation (diastole = 0.5 seconds) at 75 beats per minute Initiation of contraction - SA node (group of nerve cells); impulse spreads out over both atria causing them to contract together to force blood into both ventricles Impulse from SA node sent to AV node (between atria in septum) Impulse from AV node sent to nerve fibers in septum (bundle of His) which transmit the impulse via the right and left bundle branches to the Purkinje fibers - cause ventricles to contract together and force blood out of the aorta and pulmonary arteries to the body and the lungs Shift of ions along the conduction system = action potential Periods of rest = polarization Periods of activity = depolarization - when impulse is transmitted and repolarization - when slow shift back to polarization occurs Blood pressure Systole: maximum pressure formed during a ventricular contraction Diastole: minimum pressure during ventricular relaxation (atrial contraction) Measured in mm of Hg BP = CO x PR (blood pressure = cardiac output x peripheral resistance) Normals Systolic = 100 - 140 Diastolic = 60 - 90 Hypotension: Systolic < 90 Hypertension: Systolic > 150 and/or Diastolic > 90 FYI Factors Affecting BP Cardiac output Peripheral resistance Blood volume Circulatory Shock Hypovolemic shock Vascular shock Cardiogenic shock Causes of peripheral resistance? Abnormalities Arteriosclerosis: hardening of the arteries Atherosclerosis Fatty deposits on the walls of the arteries Factors: increased blood lipids, high blood pressure, smoking, obesity, physical inactivity, tension Hypertension 90% = essential hypertension - no specific cause 10% = symptom of another disease i.e. adrenal tumor, kidney disease Increases workload of the heart Leads to hypertrophy of left ventricle then heart failure Accelerates development of atherosclerosis Ischemic Heart Disease Oxygen supply to heart inadequate Atherosclerosis is major cause Can lead to Angina pectoris: condition in which coronary arteries are temporarily blocked - reduced blood supply to heart muscle - chest pain Heart attack: cessation of normal cardiac contraction (cardiac arrest) Myocardial infarction: necrosis (death) of heart muscle due to severe prolonged ischemia Sudden death: heart stops of ventricular fibrillation occurs Cardiac Arrhythmias Abnormality in rate, rhythm, or conduction of heart beat Bacterial Endocarditis Inflammation of the internal lining of the heart Also involves the heart valves Valvular Heart Disease – (MVP) Involves abnormalities of the heart valves Especially mitral and aortic valves Leading cause = rheumatic fever with hypersensitivity reaction to streptococcus antigens Heart valves are scarred Treatment - valve replacement Congenital Heart Disease Defects in the heart that occurred during embryologic and fetal development Involves defective communication between the chambers, malformation of valves, and malformation of septa Cyanotic: inability of individual to get adequate blood oxygenation due to extensive cardiac abnormalities that cause blood to be shunted away from lungs Example: “Blue Babies”; failure of foramen ovale to close or transposistion of great arteries or patent ductus arteriosus Some association with pregnant mother having German measles (rubella Congestive Heart Failure (CHF) Pumping action of heart diminished Fluid accumulates and is retained in tissues Compensations Increased heart rate, greater force of contraction Retention of fluid by kidneys Enlargement of heart Cor Pulmonale Hypertrophy of right ventricle due to hypertension in pulmonary circulation Increased bp in lungs - reduction in blood flow and increased resistance in lungs - pulmonary hypertension - increased pressure in pulmonary arteries - blood backs up into right ventricle - hypertrophy Peripheral Arterial Disease - Decreased blood flow to peripheral vessels Varicose Veins: enlarged veins which can be inflamed Hemorrhoids: varicose veins of rectal and anal area Aneurysm: weak section in wall of artery ballooning out - rupture Phlebitis: inflammation of a vein Thrombus: blood clot that stays where it is formed Stroke (CVA): brain infarct; caused by decreased oxygen supply to brain due to blood clot or hemorrhage Raynaud’s Disease Esophageal Varices Tetralogy of Fallot Diagnostic procedures: History and physical Angina, SOB, fatigue, dizzy, edema, claudication EKG – electrical tracing Phonocardiogram – EKG with heart sounds Echocardiogram – sound wave – size and movement Doppler ultrasound – measures blood flow Arteriography – radiopaque study – blood flow Cardiac catheterization – dye injected – flow Pulse Pulse - pg 620 Pulse wave Palpation: Radial Temporal Carotid Facial Brachial Popliteal Posterior tibial Dorsalis pedis Pressure points – pg 621 Used to control arterial bleeding Caution to never stop all blood flow Circulatory shock Cardiogenic Hypovolemic Neurogenic Anaphylactic Septic - TSS TMT Pacemaker Aorta Cardiac cath Occlusion Stroke vs heart attack List the differences Esophageal varices EV 7 d post-op CARDIAC QUESTIONS?