The Cardiovascular System

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Transcript The Cardiovascular System

The Cardiovascular System

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

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

Blood Flow Through the Heart

combines 2 circulatory systems

Pulmonary circulation

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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

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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

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

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

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)

Structure

Both arteries & veins have

3

layers of tissue

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Phleb/o- = combining form means vein

outer layer = tunica externa (adventitia)

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composed of connective tissue

middle layer = tunica media

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composed of muscle & elastic tissue

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

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 between vessel & cell 2

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

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

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

leukocytes

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

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

thrombocytes

------------250,000/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 Angina pectoris 2 block)

Infarct

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

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Pericarditis Myocarditis Endocarditis Heart murmur Cardiac arrhythmia

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

Essential hypertension

Essential = idiopathic

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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