Circulatory System: Facts, Function & Diseases

The circulatory system is a vast network of organs and vessels that is responsible for the flow of blood, nutrients, hormones, oxygen and other gases to and from cells. Without the circulatory system, the body would not be able to fight disease or maintain a stable internal environment — such as proper temperature and pH — known as homeostasis.

Description of the circulatory system

While many view the circulatory system, also known as the cardiovascular system, as simply a highway for blood, it is made up of three independent systems that work together: the heart (cardiovascular); lungs (pulmonary); and arteries, veins, coronary and portal vessels (systemic), according to the U.S National Library of Medicine (NLM).

In the average human, about 2,000 gallons (7,572 liters) of blood travel daily through about 60,000 miles (96,560 kilometers) of blood vessels, according to the Arkansas Heart Hospital. An average adult has 5 to 6 quarts (4.7 to 5.6 liters) of blood, which is made up of plasma, red blood cells, white blood cells and platelets. In addition to blood, the circulatory system moves lymph, which is a clear fluid that helps rid the body of unwanted material.

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The heart, blood, and blood vessels make up the cardiovascular component of the circulatory system. It includes the pulmonary circulation, a "loop" through the lungs where blood is oxygenated. It also incorporates the systemic circulation, which runs through the rest of the body to provide oxygenated blood, according to NLM.

[Top 10 Amazing Facts About Your Heart]

The pulmonary circulatory system sends oxygen-depleted blood away from the heart through the pulmonary artery to the lungs and returns oxygenated blood to the heart through the pulmonary veins, according to the Mayo Clinic.

Oxygen-deprived blood enters the right atrium of the heart and flows through the tricuspid valve (right atrioventricular valve) into the right ventricle. From there it is pumped through the pulmonary semilunar valve into the pulmonary artery on its way to the lungs. When it gets to the lungs, carbon dioxide is released from the blood and oxygen is absorbed. The pulmonary vein sends the oxygen-rich blood back to the heart, according to NLM.

The systemic circulation is the portion of the circulatory system is the network of veins, arteries and blood vessels that transports blood from heart, services the body's cells and then re-enters the heart, the Mayo Clinic noted.

Job of the Circulatory SystemThe Circulatory System is responsible for transporting materials throughout the entire body. It transports nutrients, water, and oxygen to your billions of body cells and carries away wastes such as carbon dioxide that body cells produce. It is an amazing highway that travels through your entire body connecting all your body cells.

Parts of the Circulatory System-

The circulatory System is divided into three major parts:

1. The Heart2. The Blood3. The Blood Vessels

The Heart-

The Heart is an amazing organ. The heart beats about 3 BILLION times during an average lifetime. It is a muscle about the size of your fist. The heart is located in the center of your chest slightly to the left. It's job is to pump your blood and keep the blood moving throughout your body. It is your job to keep your heart healthy and there are three main things you need to remember in order to keep your heart healthy.

1. Exercise on a regular basis. Get outside and play. Keep that body moving (walk, jog, run, bike, skate, jump, swim).

2. Eat Healthy. Remember the Food Pyramid and make sure your eating your food from the bottom to top.

3. Don't Smoke! Don't Smoke! Don't Smoke! Don't Smoke! Don't Smoke!

The Blood-

The blood is an amazing substance that is constantly flowing through our bodies.

Your blood is pumped by your heart. Your blood travels through thousands of miles of blood vessels right within your

own body. Your blood carries nutrients, water, oxygen and waste products to and from your

body cells. A young person has about a gallon of blood. An adult has about 5 quarts. Your blood is not just a red liquid but rather is made up of liquids, solids and

small amounts of oxygen and carbon dioxide.

Blood Cells-

Red Blood Cells-

Red Blood Cells are responsible for carrying oxygen and carbon dioxide. Red Blood Cells pick up oxygen in the lungs and transport it to all the body cells. After delivering the oxygen to the cells it gathers up the carbon dioxide(a waste gas produced as our cells are working) and transports carbon dioxide back to the lungs where it is removed from the body when we exhale(breath out). There are about 5,000,000 Red Blood Cells in ONE drop of blood.

White Blood Cells (Germinators)-

White Blood Cells help the body fight off germs. White Blood Cells attack and destroy germs when they enter the body. When you have an infection your body will produce more White Blood Cells to help fight an infection. Sometimes our White Blood Cells need a little help and the Doctor will prescribe an antibiotic to help our White Blood Cells fight a large scale infection.

Platelets-

Platelets are blood cells that help stop bleeding. When we cut ourselves we have broken a blood vessel and the blood leaks out. In order to plug up the holes where the blood is leaking from the platelets start to stick to the opening of the damaged blood vessels. As the platelets stick to the opening of the damaged vessel they attract more platelets, fibers and other blood cells to help form a plug to seal the broken blood vessel. When the platelet plug is completely formed the wound stops bleeding. We call our platelet plugs scabs.

Plasma-

Plasma is the liquid part of the blood. Approximately half of your blood is made of plasma. The plasma carries the blood cells and other components throughout the body. Plasma is made in the liver.

Where are the blood cells made?The Red Blood Cells, White Blood Cells and Platelets are made by the bone marrow. Bone marrow is a soft tissue inside of our bones that produces blood cells.

The Blood Vessels-

In class we talked about three types of blood vessels:

1. Arteries2. Capillaries3. Veins

Arteries-

Arteries are blood vessels that carry blood AWAY from the heart, much of which is oxygen rich. Remember, A A Arteries Away, A A Arteries Away, A A Arteries Away.

Capillaries-

Capillaries are tiny blood vessels as thin or thinner than the hairs on your head. Capillaries connect arteries to veins. Food substances(nutrients), oxygen and wastes pass in and out of your blood through the capillary walls.

Veins-

Veins carry blood back toward your heart.

AMAZING FACTS

One drop of blood contains a half a drop of plasma, 5 MILLION Red Blood Cells, 10 Thousand White Blood Cells and 250 Thousand Platelets.

You have thousands of miles of blood vessels in your body. "Bill Nye the Science Guy" claims that you could wrap your blood vessels around the equator TWICE!

Keep your heart healthy...it's going to have to beat about 3 BILLION times during your lifetime!

Diseases of the Circulatory SystemAccording to the American Heart Association, cardiovascular disease is the leading cause of death in the United States. Because of its vastness and critical nature, it is one of the systems of the body most prone to disease.

One of the most common diseases of the circulatory system is arteriosclerosis, in which the fatty deposits in the arteries causes the walls to stiffen and thicken the walls. According to the Mayo Clinic, the causes are a buildup of fat, cholesterol and other material in the artery walls. This can restrict blood flow or in severe cases stop it all together, resulting in a heart attack or stroke.

Stroke involves blockage of the blood vessels to the brain and is another major condition of the circulatory system, according to Mitchell Weinberg of the North Shore-LIJ Health System.  “Risk factors include smoking, diabetes and high cholesterol,” he noted.

Another circulatory disease, hypertension — commonly called high blood pressure — causes the heart to work harder and can lead to such complications as a heart attack, a stroke, or kidney failure, the NLM noted.

An aortic aneurysm occurs when the aorta is damaged and starts to bulge or eventually tear, which can cause severe internal bleeding. This weakness can be present at birth

or the result of atherosclerosis, obesity, high blood pressure or a combination of these conditions, according to Weinberg.

Peripheral arterial disease (also known as PAD) typically involves areas of narrowing or blockage within an artery, according to Jay Radhakrishnan, an interventional radiologist in Houston, Texas. In addition, chronic venous insufficiency (also known as CVI) involves areas reflux (or backward flow) within the superficial veins of the lower extremities.

PAD is diagnosed with noninvasive testing including ultrasound, CT scan, and/or MRI.  Ultrasound is the least expensive of these methods, but also gives the least amount of detail, as CT and MRI show a much higher degree of anatomic detail when identifying areas of narrowing/blockage within an artery. CVI is diagnosed with ultrasound as the venous reflux can be measured accurately by ultrasound, which ultimately guides treatment.

Study of the circulatory system

Cardiologists are specialists who are certified to diagnose, treat and prevent disease of the heart, arteries and veins. Cardiologists are certified by the American Board of Internal Medicine (ABIM) after meeting educational and practice requirements. Before being certified as cardiologists, those aspiring to the specialty must be certified in internal medicine.

Then cardiologists can become certified in one of several cardiology subspecialties, including transplant cardiology, cardiovascular disease, clinical cardiac electrophysiology and interventional cardiology.

Ready for Med School? Test Your Body SmartsYou use your eyes to see, your ears to hear and your muscles to do the heavy lifting. Well, sort of. In fact, most body parts are far more complicated than that, while some seem to have no business being inside there at all.