The Cardiovascular System The Cardiovascular System Heart Blood Vessels------Blood Cells Medical Terminology

Anatomy of the Heart 4 chambers –2 upper = right & left atria separated by interatrial septum –2 lower = right & left ventricles separated by interventricular septum –lining = 3 layers 1.Pericardium layers: a. parietal pericardium = pericardium b. visceral pericardium = epicardium peri = surrounding; epi = upon; endo = inner 2. Myocardium 3. Endocardium Heart Valves –Tricuspid = between right atrium & ventricle –Bicuspid (Mitral) = between left atrium & ventricle –Pulmonary semilunar = between R. ventricle & Pulmonary artery –Aortic semilunar = between L. ventricle & aorta

Blood Flow Through the Heart –combines 2 circulatory systems Pulmonary circulation –primarily right side of heart –key = getting blood to lungs Systemic circulation –primarily left side of heart –key = getting blood to all other parts of body

Coronary Circulation 2 coronary arteries -- --right coronary & left coronary »first two branches off ascending aorta supplies oxygen & nutrients for heart, especially myocardium

Conduction System of the Heart –Impulse route through the heart SA node (sinoatrial) = “pacemaker” »located in upper right corner of R. atrium near opening of superior vena cava »stimulates depolarization of both atria AV node (atrioventricular) »located in inferior wall of R. atrium near a-v septum »stimulates the initiation of depolarization of both ventricles »slowing of impulses through this node allows time for the ventricles to fill with blood from the contracting atria Bundle of His »located at top of interventricular septum Right Bundle Branch & Left Bundle Branch Purkinje’s Fibers

Electrocardiogram The electrical impulses traveling through the heart are picked up at the patient’s skin surface by a machine (electrocardiograph) 5 basic parts 1. P wave = atrial depolarization & contraction 2. P-R interval = time it takes from beginning of atrial contraction to beginning of ventricular contraction 3. QRS wave = ventricular depolarization & contraction 4. S-T segment = time it takes from end of ventricular contraction to the beginning of ventricular recovery 5. T wave = repolarization of the ventricles

Blood Vessels Blood Vessels vascular system --- vas = vessel (Latin) Structure –Both arteries & veins have 3 layers of tissue »Phleb/o- = combining form means vein outer layer = tunica externa (adventitia) »composed of connective tissue middle layer = tunica media »composed of muscle & elastic tissue inner layer = tunica intima »composed of endothelium »Veins have one-way flow valves from the endothelium –Capillaries : only one ( 1 ) layer of endothelial cells –Arterioles = small arteries –Venules = small veins

Vessels –Arteries carry blood away from heart –Capillaries join arteries and vein Microscopic Nutrients and oxygen exchanged at cellular level –Veins carry blood to the heart

Functions of Blood Vessels Arteries –distribution of nutrients –maintenance of blood pressure Veins –takes waste products back to heart for circulation & disposal –valves keep flow going in one direction Capillaries –where internal respiration occurs »i.e. the exchange of O 2 & CO 2 between vessel & cell –where exchanges occur for nutrients, wastes, and fluids

Blood Composition Blood = Plasma (55%) + Formed Elements (45%) –Plasma = the liquid faction of blood; blood minus its formed element –Serum = plasma minus clotting factors

–Formed Elements “The Cells” Red Blood Cells erythrocytes million/mm 3 White Blood Cells leukocytes /mm 3 Platelets thrombocytes ,000/mm 3

Types of WBC’s –granular: »neutrophils (60%) phagocytes; first line of defense »eosinophils (3%) seen in allergies & parasitic diseases »basophils (1%) release heparin & histamine –nongranular: »lymphocytes (30%) * B lymphocytes * T lymphocytes »monocytes (5%) become macrophages

Blood Diseases Essentially one gets Too Much or Too Little RBC polycythemia anemia Platelets thrombocytosis thrombocytopenia WBC leukocytosis leukopenia (-penia = poverty) Cancer of WBC’s = Too Much = leukemia

Cardiovascular Pathology Coronary artery disease –Ischemia (partial O 2 block) Angina pectoris –Infarct (complete O 2 block) Myocardial infarction Congestive heart failure Carditis –Pericarditis –Myocarditis –Endocarditis Heart murmur Cardiac arrhythmia –Tachycardia (2X) –Flutter (3X) –Fibrillation (4X)

Aneurysm Raynaud’s phenomenon Thrombosis Phlebitis Varicose veins Thrombophlebitis Embolus Hypertension –Essential hypertension Essential = idiopathic –Secondary hypertension –Malignant hypertension

Cardiovascular Procedures & Treatments Cardiac catheterization Stress test –Thallium stress test Echocardiography Angioplasty Endarterecomy (endo-; arter/o; -ectomy) CABG Valvuloplasty Pacemaker Defibrillation

Arteriolar disease Arteriosclerosis Atherosclerosis Thrombosis Embolus CVA = stroke = cerebrovascular accident