Cardiovascular System Body Systems and Disorders

The Heart About the size of a closed fist Weighs about 1 pound Located in thoracic cavity; apex of heart lies on the diaphragm and points to the left of the body

The Heart After 4 to 5 minutes without blood flow, the brain cells are irreversibly damaged Can hear the heartbeat through the stethoscope

Structure of the Heart Hollow, muscular, double pump: circulates the blood through the blood vessels to all parts of the body. Pericardium: double layer of fibrous tissue that surrounds the heart. Myocardium: cardiac muscle tissue. Makes up major portion of heart. Endocardium: inner lining. Covers heart valves and lines the blood vessels.

Structure of the Heart Superior and inferior vena cava – bring deoxygenated blood to the heart from all parts of the body. Pulmonary artery – takes blood away from the right ventricle to the lungs for oxygen Pulmonary veins – bring oxygenated blood from the lungs to the left atrium. Aorta – takes blood away from the left ventricle to the rest of the body.

Chambers and Valves Separated into right and left halves by septum; then each half separated into an upper and lower chamber Upper chambers Left and right atria: or if describing individually would be call atrium – i.e. right atrium, left atrium

Chambers and Valves Low chambers Left and right ventricles Valves keep blood flow going in one direction

Valves Atrioventricular valves Tricuspid valve: positioned in between the right atrium and the right ventricle. Bicuspid or mitral valve: positioned between the left atrium and the left ventricle. Semilunar valves: are located where blood will leave the heart. Pulmonary semilunar valve: found at the opening of the pulmonary artery. It allows blood to travel from the right ventricle into the pulmonary artery, and then into the lungs. Aortic semilunar valve: found at the opening of the aorta. It allows blood to pass from the left ventricle into the aorta, but not backwards into the left ventricle.

Physiology of the Heart Double pump Right heart Deoxygenated blood Left heart Oxygenated blood

Heart Sounds Valves make a sound when they close Called lubb dupp sounds Lubb – heard first and is made by the Triscuspid & Bicuspid valves closing between the atria and ventricles. Dupp – heard second and is shorter and higher pitched. Is made by the semilunar vales in the aorta and the pulmonary artery closing.

Conduction System Electrical impulses cause rhythmic beating of heart Sinoatrial (SA) node or pacemaker: sends out electrical impulse that spreads out over atria, making them contract. Atrioventricular (AV) node: electrical impulse continues to AV node which then sends electrical impulse to conducting fibers in septum (Bundle of His) Bundle of His: divides into a right and left branch, spreading throughout the ventricles, which then subdivides into a fine network call the Purkinje network. Purkinje fibers: the electrical impulse then shoots along the Purkinje fibers to the ventricles causing them to contract.

Diagnostic Tests Noninvasive Angiography: x-ray that uses dye injected into the coronary arteries to study the circulation of the blood through the arteries. Echocardiography: directs ultrasound waves at the heart that are then processed to provide video images of the heart and chambers. Electrocardiogram (ECG or EKG): device used to record the electrical activity of the heart.

Diagnostic Tests Noninvasive Exercise stress tests (treadmill test): given while patient walks on a treadmill to see if exercise brings on changes in the EKG. Holter monitor: small, portable, battery-operated EKG machine worn by the patient to record EKG on tape over a period of 24-48 hours.

Diagnostic Tests Invasive Cardiac catheterization: insertion of catheter, usually in femoral artery or vein. Dye is inserted and pictures are taken as fluid moves through the chambers. IVUS (intravascular coronary ultrasound): a combination of echocardiography and cardiac catheterizations. Uses sound waves to produce an image of the coronary arteries.

Diagnostic Tests Blood Tests Arterial blood gases: measures the amount of oxygen in the blood and the amount of carbon dioxide. Lipid panel: measures cholesterol, LDL, HDL and triglycerides levels. Cardiac enzymes: blood is checked for enzymes that are released by the damaged heart muscle. Prothrombin time tests: monitors anticoagulation therapy.

Diseases of the Heart – Common Symptoms Arrhythmia: term used to discuss any change or deviation from the normal rate or rhythm of the heart Bradycardia: slow heart rate (less than 60 beats per minute) Tachycardia: rapid heart rate (more than 100 beats per minute) Murmurs: indicates some defects in the valves of the heart. When valves fail to close properly, a gurgling or hissing sound will occur Mitral valve prolapse: valve between left atria and left ventricle closes imperfectly.

Diseases of the Coronary Artery Coronary artery disease (CAD): narrowing of the arteries that supply oxygen and blood to the heart muscle. Angina pectoris: severe chest pain that arises when the heart does not receive enough oxygen. Myocardial infarction: MI or Heart attack. Caused by lack of blood supply to the heart muscle.

Heart Failure When the ventricles of the heart are unable to contract effectively and blood pools in the heart. Symptoms depend on which ventricle fails: if left ventricle fails, dyspnea occurs. If right ventricle fails, engorgement of organs with venous blood occurs.

Congestive Heart Failure Similar to heart failure plus edema of the lower extremities and blood backs up into the lungs. Treatment: drugs that reduce the amount of fluid in the body. Vasodilators that lower blood pressure and improve blood flow.

Types of Heart Surgery Angioplasty: small deflated balloon is threaded into the coronary artery. When it reaches the blocked area, the balloon is inflated. Coronary bypass: surgically providing a detour or bypass to allow the blood supply to go around the blocked area of the coronary artery. Cardiac stents: tiny webbed, stainless steel devices, which hold arteries open after an angioplasty.

Heart Transplants Used as last resort: when the individual’s own heart can no longer function properly. Histocompatibility: tissue type must match Organ rejection: body will sometimes reject organ

Cardiovascular System Medical Terminology