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