Transcript The Cardiovascular System
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