The Cardiovascular SystemThe Cardiovascular SystemHeart-------Blood Vessels------Blood Cells
Medical TerminologyMedical Terminology
Anatomy of the HeartAnatomy 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 --- 2 layers:
a. parietal pericardium = pericardiumb. visceral pericardium = epicardium
peri = surrounding; epi = upon; endo = inner2. Myocardium3. 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
ElectrocardiogramElectrocardiogram• 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 VesselsBlood Vesselsvascular 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 O2 & CO2 between vessel & cell
– where exchanges occur for nutrients, wastes, and fluids
Blood CompositionBlood 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------------- 5 million/mm3
• White Blood Cells ------------leukocytes---------------5000/mm3
• Platelets --------------------thrombocytes------------250,000/mm3
• 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 DiseasesBlood 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 PathologyCardiovascular Pathology• Coronary artery disease
– Ischemia (partial O2 block)
• Angina pectoris– Infarct (complete O2 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 & TreatmentsCardiovascular 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