Cardiovascular System Overview

Cardiovascular System Overview

• Responsible for circulating blood throughout the body
• Delivers oxygen and nutrients to tissues
• Removes waste products
• Composed of the heart, blood vessels, and blood
• Maintains homeostasis and supports vital functions
• Regulates blood pressure
• Maintains fluid balance
• Enables immune responses through the transportation of white blood cells

The Heart

• Right atrium receives blood low in oxygen from all body tissues through the superior vena cava and the inferior vena cava
• Blood then enters the right ventricle and is pumped to the lungs through the pulmonary artery.
• Blood returns from the lungs high in oxygen and enters the left atrium through the pulmonary veins
• Blood enters the left ventricle and is forcefully pumped into the aorta to be distributed to all tissues.

The Vascular System

• Arteries: Carry blood away from the heart (except for pulmonary and umbilical arteries which carry oxygenated blood)
• Arterioles: Smaller vessels that carry blood from the arteries into the capillaries
• Capillaries: Smallest vessels where exchanges take place between blood and tissues
• Venules: Small vessels that receive blood from the capillaries and drain into the veins
• Veins: Carry blood back to the heart (except for pulmonary and umbilical veins which carry blood low in oxygen)

Terminology of the Cardiovascular System

• Artery: Vessel that carries blood away from the heart
• Arteriole: Small vessel that carries blood from the arteries into the capillaries
• Vein: Vessel that carries blood back to the heart
• Venule: Small vessel that carries blood from the capillaries to the veins
• Valve: Structure that keeps fluid flowing in a forward direction
• Sinoatrial (SA) node: A small mass in the upper part of the right atrium that initiates the impulse for each heartbeat; the pacemaker
• Systole: The contraction phase of the heartbeat cycle

Cardiovascular System Disorders

• Aneurysm: Localized abnormal dilation of a blood vessel, usually an artery, caused by weakness of the vessel wall; may eventually burst
• Angina pectoris: Feeling of constriction around the heart or pain that may radiate to the left arm or shoulder, usually brought on by exertion; caused by insufficient blood supply to the heart
• Arrhythmia: Any abnormality in the rate or rhythm of the heartbeat
• Atherosclerosis: Development of fatty, fibrous patches (plaques) in the lining of arteries, causing narrowing of the lumen and hardening of the vessel wall
• Dyslipidemia: Disorder in serum lipid levels, which includes hyperlipidemia, hypercholesterolemia, and hypertriglyceridemia
• Bradycardia: Slow heart rate of less than 60 bpm
• Tachycardia: Fast heart rate of more than 100 bpm at rest
• Dyspnea: Difficult or labored breathing
• Edema: Swelling of body tissues caused by the presence of excess fluid
• Heart failure: Inability of the heart to maintain adequate blood circulation
• Hypertension: Higher-than-normal blood pressure
• Myocardial infarction (MI): Localized necrosis (death) of cardiac muscle tissue resulting from blockage or narrowing of the coronary artery
• Embolism: Obstruction of a blood vessel by a blood clot or other matter carried in the circulation
• Ischemia: Local deficiency of blood supply caused by circulatory obstruction
• Stroke: Sudden damage to the brain resulting from reduction of blood flow
• Shock: Circulatory failure resulting in an inadequate blood supply to the tissues

Diagnostic Tools

• Coronary angiography: Radiographic study of the coronary arteries after introduction of an opaque dye
• Echocardiography (ECG): Non-invasive method that uses ultrasound to visualize internal cardiac structures