INTRODUCTION:

    The heart is a spectacular muscular organ that beats every second, of every day. It is positioned behind the ribcage and between the lungs. It tilts slightly to the left. It also supplies your body with what it needs to live, fresh oxygenated blood.

Blood that is rich in oxygen appears red. Blood that is poor in oxygen appears blue.

    Arteries are tough, elastic tubes that carry blood away from the heart. Veins carry the blood to the heart.

    The circulatory system is made up of the vessels and the muscles that help and control the flow of the blood. This process is called circulation.

THE HEART:

    The heart is the most vital organ in the circulatory system. It is composed of 4 main sections: the right and left ventricle and the right and left atrium. The heart acts like a pump that forces the blood through an interconnecting system of vessels which eventually return to the heart. So this is your heart, your ticker, without it you wouldn't be here. It supplies your body with what it needs to live. You notice the heart in the picture above is two different colors: red and blue. The red is oxygen enriched blood from the lungs and the blue is oxygen deficient blood which has returned from the body. The heart is the pump that keeps this transport system moving.

    The structure of the heart is divided into four main sections the left and right atrium and the left and right ventricle. The blood enters the heart from its long journey around the body through the superior and inferior vena cava into the right atrium. This blood has very little if any oxygen. Then it passes by the tricuspid valve into the right ventricle. After the right ventricle contracts, the blood is forced past the pulmonary semilunar (crescent shaped) valve, and into the pulmonary trunk which is an artery. The pulmonary trunk splits into the right and left pulmonary artery where the still oxygen deficient blood travels through the lungs. The blood becomes enriched with oxygen and travels back toward the heart. The blood enters the heart via the right and left pulmonary vein which come directly from the lungs. The blood then enters the left atrium. The bicuspid valve opens up and the blood falls into the left ventricle. The ventricle contracts and the blood goes rushing passed the aortic semilunar valve and into the aorta which is the largest artery in the body. Now the blood is on its way back to the body.

    The heart pumps oxygen into the blood and collects carbon dioxide from it to be expelled through the lungs.

    To see how big your heart is, make a fist. Your heart beats about 60-100 times per minute. Your heart beats every second, of every day. In one year your heart beats more than 30,000,000 times. In an average lifetime a heart will beat over 2,000,000,000 times. Our heart never stops for rest or repair. The heart weighs about 10 ounces, about as much as one of your sneakers. It is located in the middle of your chest tilted slightly to the left.

BLOOD:

    The blood is the transport system by which oxygen and nutrients reach the body's cells, and waste materials are carried away.

    Blood that is rich in oxygen appears red.

    Blood that is poor in oxygen appears blue.

    Blood is that sticky, red fluid that circulates throughout our bodies in veins and arteries.

    Red blood cells carry oxygen from the lungs to all the cells of the body.

    White blood cells are like soldiers protecting the body.

BLOOD VESSELS:

    Blood leaves the left side of the heart and travels through arteries, which gradually divide into capillaries. In the capillaries, food and oxygen are released to the body cells, and carbon dioxide and other waste products are returned to the bloodstream.

Veins and Arteries

Blood Vessels

    The blood vessles are an network of interconecting veins and arteries and their sub catagories. They provide the pathway in which blood travles. The catagories from largest to smallest and back to largest are as follows:

    Aorta Arteries Arterioles
    Capillaries
    Venules Veins Vena Cava

    These are the different kinds of vessles in the body.

    The AORTA is the largest artery in the body. It pertrudes out of the top of the left vetricle of the heart.
The ARTERIES are blood vessels which carry blood blood away from the heart. Usually the blood in arteries is deoxygenated except for in the pulmonary trunk. They have an elastic wall and their cell walls are thicker than veins. Arteries' walls are divided into three layers: the endothlium which is the innermost layer, see if you can guess the name of the middle layer... if you guesed the Middle layer then you are correct, it is a thick layer of muscle tissue. Alright go two for two; see if you can guess the name of the outer layer... that's right The Outer layer, and it is a tough elastic covering. As the arteries progressively get smaller and smaller they become called ARTERIOLES.
    The CAPILLARIES are the smallest of the blood vessels. It is in them which gas exchanges take place. The capilaries are the bridge from the arterioles to the venules. The membrane of capilaries is very thin and permeable.
The VENULES are microscopic vessels that continue from the capillaries to merge to form veins.

    ARTERIES are vessels that carry blood away from the heart.

    VEINS are vessels that carry blood back to the heart.

PATH OF CIRCULATION:

    Blood leaves the left side of the heart and travels through arteries which gradually divide into capillaries. The blood then travels in veins back to the right side of the heart, where it is pumped directly to the lungs. In the lungs, carbon dioxide is exchanged for oxygen, and this renewed blood flows back to the left side of the heart, and the whole process begins again.

    The majors parts of the circulatory system are the heart, arteries and veins. The heart pumps blood to the arteries. The arteries take the oxygenated blood to the muscles. The veins take blood back to the heart, which then releases carbon dioxide in the lungs

    How the Blood Gets Around the Body

    The circulatory system is made up of the vessels and the muscles that help and control the flow of the blood around the body. This process is called circulation. The main parts of the system are the heart, arteries, capillaries and veins.

    As blood begins to circulate, it leaves the heart from the left ventricle and goes into the aorta. The aorta is the largest artery in the body. The blood leaving the aorta is full of oxygen. This is important for the cells in the brain and the body to do their work. The oxygen rich blood travels throughout the body in its system of arteries into the smallest arterioles.

    On its way back to the heart, the blood travels through a system of veins. As it reaches the lungs, the carbon dioxide (a waste product) is removed from the blood and replace with fresh oxygen that we have inhaled through the lungs.

    The circulatory system also known as the cardiovascular system is composed of the heart and blood vessels. Its function is to transport blood which contains oxygen and nutrients to all parts of the body. Also it carries cellular wastes away to be filltered out of the body.

    The cardiovascular system includes the heart and the blood vessels, and the respiratory system contains those organs which are responsible for carrying oxygen from the air to the blood stream and expelling the waste product of carbon dioxide.

    Blood CIRCULATES--circles--all around your body in about one or two minutes.

    Inside the heart are four hollow chambers. Each chamber is a little pump. The pumping pushes blood all around your body.

MISCELLANEOUS:

    The circulatory system is like a water system because the pipes are like the veins and arteries and the water plant is like the heart.

WORDS TO HELP YOU:

    Aorta – largest artery of the body

    Arteries – tough elastic tubes that take the blood away from the heart

    Arterioles – microscopic vessels that merge into capillaries from arteries

    Bicuspid valve – a cardiac valve consisting of two triangular flaps

    Blood – sticky red fluid that circulates throughout our bodies in veins and arteries

    Capillaries – the smallest of the blood vessels

    Carbon dioxide – a waste product

    Cardiovascular system – the system of our body having to do with the heart and blood vessels

    Circulation – the movement of blood, through the vessels of the body caused by the pumping of the heart.

    Circulatory system –system of blood, blood vessels and lymphatics and heart concerning the circulation of the blood and lymph

    Corpuscles – a minute particle, a living cell. One red blood cell or one white blood cell

    Heart – The pump and the most efficient organ in the body as it pumps it circulates the blood

*** Left atrium – the chamber in the heart that receives blood from the veins and forces it into the ventricles

*** Left ventricle – a chamber of the heart which receives blood from the corresponding atrium and from which blood is forced into the arteries

    Lungs – thoracic organs which make up the basic respiratory organ of air breathing vertebrate

    Organ - body parts performing a function consisting of cells and tissues

    Oxygen – a colorless tasteless odorless gas that every cell in your body needs to survive

    Platelets – one of the minute disks of vertebrate blood that assists in blood clotting.

    Pulse – your heart beat felt by your fingers at your neck or wrist

    Red blood Cells - carry oxygen from the lungs to all the cells of the body.

*** Right atrium - – the chamber in the heart that receives blood from the veins and forces it into the ventricles

*** Right ventricle – the chamber in the heart that receives blood from the veins and forces it into the ventricles

    Semilunar valve – crescent shaped valve

    Septum – the muscular wall separating the chambers of the heart

    Ticker – a nickname or slang word for heart.

    Tricuspid valve – a cardiac valve consisting three triangular valves

    Veins – are blood vessels, which carry blood back to the heart.

    Vena Cava – the largest vein.

    Venules – microscopic vessels that continue from the capillaries, merge to form veins.

    Vessels – a network of veins and arteries

    White blood cells – are like soldiers protecting the body.