The Cardiovascular System

The Cardiovascular System

1. Consists of heart and blood vessels, Circulates blood throughout body, Delivers oxygen and nutrients to cells, Carries away waste products.

   • Located between lungs Layers of the heart
     • Endocardium = inside lining; lines chambers and valves
     • Myocardium = thick muscular layer that makes up heart wall
     • Epicardium = outside thin lining; covers heart
       • Pericardium = surrounding fibrous sac Atria = upper receiving chambers (singular: atrium)
   • Ventricles = Lower pumping chambers (singular: ventricle)
     • Pulmonary circuit (right side to lungs) Systemic circuit (left side to rest of body)
     • Chambers separated by septa (walls) Pumps blood through two circuits Pulmonary = right side to lungs; to be oxygenated Systemic = left side; oxygenated blood to body
   • The Heartbeat
     • Systole = contraction Diastole = relaxation
     • Heartbeat starts with both atria contracting Heart rate = number of times heart contracts per minute Pulse = wave of increased pressure as ventricles contract
     • Ventricles contract; contractions are stimulated by electrical impulse
       • Sinoatrial node (SA node) Atrioventricular node (AV node) AV bundle Bundle branches Purkinje fibers

2. Atherosclerosis

   • Accumulation of fatty deposits within artery
     • Risk factors
       • High levels of lipoproteins (especially LDLs) Smoking High blood pressure Poor diet Inactivity Stress Family history

3. Thrombosis and Embolism

   • Thrombosis = formation of blood clot Thrombus = blood clot resulting in tissue death Embolism = obstruction of a blood vessel by a blood clot or other matter carried in the circulation Embolus = a mass carried in the circulation; usually a blood clot

4. Aneurysm

   • Weakened arterial wall ballooning out
     • Caused by
       • Atherosclerosis Malformation Injury Dissecting aneurysm sometimes ruptures vessel; possible to fix with graft

5. Hypertension

   • Commonly known as high blood pressure Contributing factor in many conditions Defined as systolic >130 mmHg, diastolic >80 mmHg Causes left ventricle to enlarge First defense: diet and life habits

6. Rheumatic heart disease

   • Streptococcus infection damaging heart valves Treated with antibiotics May require surgical correction or valve replacement

7. Arrhythmia

   • Irregularity of heart rhythm Bradycardia = slower than average Tachycardia = faster than average Fibrillation = extremely rapid, ineffective

8. Heart Disorders

   • Coronary artery disease
     • Results from atherosclerosis Early sign is angina pectoris (chest pain)
     • Diagnosed by
       • ECG Stress tests Coronary angiography Echocardiography
   • Myocardial infarction
     • Symptoms (varies between genders): Precordial or epigastric pain Pain extending to jaw, arms, shoulder Pallor (turns pale) Diaphoresis Nausea Dyspnea (difficulty breathing) May also be burning sensation similar to heartburn

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