CHAPTER 8HAVE A HEART

SAM ERB

Functions of the Cardiovascular System

• Delivers O2, nutrients, & hormones

• Transports waste products

Consists of: the heart, blood vessels, and blood

Structures of the Heart• The Heart• Hollow, muscular organ• Located inside thoracic cavity• Layers: (external to internal) Epicardium,

Myocardium, Endocardium• The Pericardium• Double-walled membrane surrounding the

heart• Chambers• Upper chambers: Atria• Lower chambers: Ventricles• Blood flow within chambers is controlled by

valves• Apex: “triangular” bottom of heart

Blood Flow

• Arteries away from heart

• Veins toward heart

• Sinoatrial node and Purkinje fibers establish rhythm

• Electrical impulses from SA node travel to atrioventricular node (atria contract)

• Impulse then sent to bundle of His and ventricular muscle (ventricles contract)

Anatomy of an Electrocardiogram

• What it does?• Measures electrical activity of

myocardium• P Wave: depolarization of atria• QRS Complex: depolarization of

ventricles• T Wave: repolarization of ventricles

Common Tests & Ailments

• Angiography• Study of blood vessels using

contrast material• Radiography

• Imaging objects by exposing sensitized film to X-rays

• EKG

• Aneurysm: balloon-like enlargement of artery

• Hypoxia: below-normal levels of O2

• Occlusion: blockage in vessel or passageway

• Atherosclerosis: hardening and narrowing of arteries

Common Procedures

• Angioplasty: surgical repair of blood or lymph vessels

• Transfusion: introduction of whole blood or blood components

• Defibrillation: electrical shock used to restore normal heart rhythm

• Stent: small expander implanted in blood vessel to prevent collapse