The Cardiovascular System

Heart-------Blood Vessels------Blood Cells Medical Terminology

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Anatomy of the Heart

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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 = pericardium b. visceral pericardium = epicardium peri = surrounding; epi = upon; endo = inner 2. Myocardium 3. Endocardium

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Heart Valves Tricuspid = between right atrium & ventricle

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Bicuspid (Mitral) = between left atrium & ventricle Pulmonary semilunar = between R. ventricle & Pulmonary artery Aortic semilunar = between L. ventricle & aorta

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Blood Flow Through the Heart

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combines 2 circulatory systems

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Pulmonary circulation

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primarily right side of heart key = getting blood to lungs

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Systemic circulation

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primarily left side of heart key = getting blood to all other parts of body

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Coronary Circulation

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2 coronary arteries -- -right coronary & left coronary

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first two branches off ascending aorta

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supplies oxygen & nutrients for heart, especially myocardium

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Conduction System of the Heart

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Impulse route through the heart

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SA node

» »

(sinoatrial) = “pacemaker” located in upper right corner of R. atrium near opening of superior vena cava stimulates depolarization of both atria

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AV node (atrioventricular)

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located in inferior wall of R. atrium near a-v septum

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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

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Bundle of His

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located at top of interventricular septum

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Right Bundle Branch Purkinje’s Fibers & Left Bundle Branch

Electrocardiogram

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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

vascular system --- vas = vessel (Latin)

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Structure

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Both arteries & veins have

3

layers of tissue

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Phleb/o- = combining form means vein

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outer layer = tunica externa (adventitia)

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composed of connective tissue

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middle layer = tunica media

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composed of muscle & elastic tissue

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inner layer = tunica intima

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composed of endothelium

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Veins have one-way flow valves from the endothelium

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Capillaries : only one (

1

) layer of endothelial cells Arterioles = small arteries Venules = small veins

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Vessels

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Arteries carry blood away from heart

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Capillaries join arteries and vein

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Microscopic

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Nutrients and oxygen exchanged at cellular level

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Veins carry blood to the heart

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Functions of Blood Vessels

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Arteries

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distribution of nutrients

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maintenance of blood pressure

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Veins

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takes waste products back to heart for circulation & disposal

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valves keep flow going in one direction

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Capillaries

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where internal respiration occurs

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i.e. the exchange of O 2 & CO between vessel & cell 2

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where exchanges occur for nutrients, wastes, and fluids

Blood Composition

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Blood = Plasma (55%) + Formed Elements (45%)

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Plasma = the liquid faction of blood; blood minus its formed element

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Serum = plasma minus clotting factors

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Formed Elements

---------- “The Cells”

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Red Blood Cells------------

erythrocytes

------------- 5 million/mm 3

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White Blood Cells ------------

leukocytes

---------------5000/mm 3

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Platelets --------------------

thrombocytes

------------250,000/mm 3

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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

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Essentially one gets Too Much or Too Little

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RBC ---------------- polycythemia ---------------- anemia

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Platelets ---------- thrombocytosis ------------ thrombocytopenia

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WBC---------------- leukocytosis ------------------leukopenia (-penia = poverty)

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Cancer of WBC’s = Too Much = leukemia

Cardiovascular Pathology

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Coronary artery disease

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Ischemia

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(partial O Angina pectoris 2 block)

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Infarct

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(complete O 2 block) Myocardial infarction Congestive heart failure Carditis

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Pericarditis Myocarditis Endocarditis Heart murmur Cardiac arrhythmia

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Tachycardia (2X)

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Flutter (3X) Fibrillation (4X)

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Aneurysm Raynaud’s phenomenon Thrombosis Phlebitis Varicose veins Thrombophlebitis Embolus Hypertension

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Essential hypertension

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Essential = idiopathic

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Secondary hypertension Malignant hypertension

Cardiovascular Procedures & Treatments

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Cardiac catheterization Stress test

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Thallium stress test Echocardiography Angioplasty Endarterecomy (endo-; arter/o; -ectomy) CABG Valvuloplasty Pacemaker Defibrillation

Arteriolar disease

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Arteriosclerosis Atherosclerosis Thrombosis Embolus CVA = stroke = cerebrovascular accident