Sistema Cardiovascular

Cardiovascular System

The cardiovascular system is responsible for transporting oxygenated blood from the lungs to the body's tissues, delivering nutrients and removing waste products through circulation. It consists of two primary components: the heart and the circulatory system.

Heart Anatomy

The human heart is a muscular organ approximately the size of a fist and weighs around 120 grams. It is located between the lungs in the chest cavity and has four chambers: the left and right atria, and the left and right ventricles.

1. Atria: These are the upper chambers of the heart where deoxygenated blood from the body enters the right atrium and oxygenated blood returns from the lungs enters the left atrium.

2. Ventricles: The lower chambers of the heart, the left and right ventricles, pump oxygenated and deoxygenated blood to the rest of the body.

The heart functions by contracting and relaxing, allowing it to pump blood throughout the body. This contraction and relaxation are facilitated by electrical impulses called pacemaker cells, which initiate each heartbeat.

Circulatory System Function

The circulatory system is divided into three main parts: arteries, capillaries, and veins.

Arteries

Arteries carry oxygenated blood away from the heart to the body's tissues. They have thick walls to withstand the high pressure exerted by the force of the blood flowing out of the heart.

Capillaries

Capillaries connect arteries and veins and are the smallest blood vessels in the body. Oxygen and nutrients diffuse from the capillary fluid into surrounding tissues while carbon dioxide and other wastes move from the tissue back into the bloodstream.

Veins

Veins collect deoxygenated blood from the tissues, returning it to the heart, which is then delivered to the lungs for re-oxygenation. Unlike arteries, veins have thin walls and rely on skeletal muscle contractions during movement to help propel the blood against gravity, especially when moving upward in the body.

Cardiovascular Diseases

Cardiovascular diseases affect the heart and blood vessels, leading to various complications including hypertension (high blood pressure), coronary artery disease (CAD) - also known as angina pectoris - and strokes.

Hypertension

Hypertension occurs when blood pressure is consistently higher than normal, often due to factors like obesity, sedentary lifestyle, smoking, alcohol consumption, stress, older age, or genetic predisposition. Continuous high blood pressure increases the risk of developing heart failure, stroke, peripheral vascular disease, kidney damage, and vision loss.

Coronary Artery Disease (CAD)

Coronary artery disease (CAD) is caused by plaque buildup within the walls of the coronary arteries, reducing blood flow to the heart muscle, causing pain (angina). Unstable plaques can rupture, triggering blood clot formation, potentially leading to heart attack or death. CAD risks can be reduced by maintaining optimal blood lipid levels, controlling high blood pressure, being physically active, eating a healthy diet rich in fruits and vegetables, and avoiding tobacco and excessive alcohol.

Strokes

A stroke occurs when blood supply to part of the brain is interrupted or reduced, causing brain cells to become damaged or die. This may lead to temporary or permanent disabilities depending on the severity and location of the affected area. Risk factors for stroke include hypertension, cigarette smoking, alcoholism, diabetes mellitus, increased age, and a family history of stroke.

Blood Vessels

Blood vessels play a critical role in carrying blood throughout the body. They include arteries, veins, and capillaries.

Arterioles

Arterioles are tiny vessels connecting small arteries to capillaries. Their walls contain smooth muscles, which can constrict or relax, regulating blood flow to specific areas of the body based on demand.

Venules

Venules are tiny vessels connecting capillaries to veins. They transport blood back toward the heart.

In summary, the cardiovascular system plays a crucial role in providing oxygen and nutrients to the body's tissues while removing metabolic waste. Understanding its structure and function helps us recognize potential issues and maintain overall health.