Circulatory System

July 21, 2010

The role of the circulatory system is twofold: it delivers oxygen and nutrients to all parts of the body while picking up waste and toxic materials that need to be eliminated. It accomplishes this monumental task trough a network of nearly 60,000 miles of blood vessels and a fist-sized organ, the heart, which pumps more than 2,000 gallons of blood through its chambers each day.

Transporting Your Life Blood

Blood vessels are divided into three main categories: arteries, veins and capillaries. Arteries are thick-walled vessels that carry blood from the heart to all parts of the body. Each time a person’s heart beats, the elastic walls of the arteries swell to make room for the blood that is forced into them. The muscles inside the walls contract slowly, in effect squeezing the blood and forcing it to move along the arteries toward the capillaries. If arteries lose their elasticity – known as arteriosclerosis (hardening of the arteries) – the heart has to work much harder to keep the blood circulating. Like a machine, if the heart is overworked and not properly maintained, it cannot function optimally.

The Lymphatic System

In addition to moving the blood along, the squeezing process forces fat globules, tiny protein particles and other nutrients to go outside of vessel walls. Once these things are out, due to their size, they cannot re-enter. Instead, they are collected along with other cellular debris lying between cells.

The lymphatic system picks up these particles and mixes them with plasma, which forms lymph. The lymph is then purified, recycled in the lymph nodes, and added back to the blood. This process, which is vital to the circulatory system, is also essential to the success of the immune system.

The Return Trip

Veins are thin-walled blood vessels. Their purpose is to return the blood from the body to the heart. Many larger veins have valves to prevent a back-flow of blood. If these valves experience prolonged or excessive pressure, veins can become overstretched, and the valves may be destroyed or rendered incompetent. This results in problems like varicose veins.

Capillaries are the smallest blood vessels in the body. They serve as intermediaries, connecting arteries with veins. Since capillaries are extremely small and have permeable walls, it’s possible for capillaries to reach nearly every cell in the body and to transfer substances, including important nutrients, to and from the tissues.

The Heart

The heart is made up primarily of muscles that facilitate its pumping action. This most vital of organs consists of four compartments or chambers. The upper two are referred to as the atria, and the lower two as ventricles. Oxygen-poor blood enters the right atrium and moves through it to the right ventricle. From there, blood is sent via the pulmonary arteries to the lungs so that it can pick up a fresh supply of oxygen. Once it has taken on a supply of oxygen, blood moves through the pulmonary veins – first to the left atrium and then to the left ventricle.

The heartbeat is sustained by the sinoatrial (SA) node, which functions as a pacemaker. A healthy heart has a regular beat, although the rate can vary depending on several factors including age, sex, physical activity and emotion.

Health Factors

For the circulatory system to function properly, the heart must be strong, the vessels capable of safely transporting optimal amounts of blood, and the blood itself must be healthy. Serious problems can arise when these conditions are not met. Each year approximately 25 percent of all deaths in the U.S. occur from heart attacks. and the majority of these are attributable to hardening of the arteries. In addition to heart attacks, a poor circulatory system can lead to strokes, kidney disease, varicose veins, blood clots and a variety of other conditions that can kill or severely limit the enjoyment of life.

Three major factors that contribute to circulatory problems are hypertension (high blood pressure), high triglycerides and cholesterol in the bloodstream, and smoking. Nutrition has been linked directly to hypertension and high levels of triglycerides and cholesterol. Other factors include obesity, heredity and emotional stress. Unfortunately, the threat of problems increases significantly when more then one factor is present. That means that when a person has three risk factors, his chances for disease are six times greater than when only one is present.

How can you maintain a healthy circulatory system? Most experts agree that the keys are to avoid smoking, monitor your diet, exercise regularly and manage stress.

Reference:

NSP from A to Z, Plus Body Systems and Sales Aids

Posted by Terry | Filed Under Body Systems | Leave a Comment