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Chapter 30.1 The Circulatory. Functions of the Circulatory System : supplies the trillion cells in your body with nutrients & oxygen transports hormones throughout your body and carries wastes away from cells repairs tissues and protects the body from infection removes carbon dioxide.
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Functions of the Circulatory System: • supplies the trillion cells in your body with nutrients & oxygen • transports hormones throughout your body and carries wastes away from cells • repairs tissues and protects the body from infection • removes carbon dioxide
Main Organs: 1. Blood - connective tissue made of cells and liquid. 55% is plasma / 45% mostly blood cells.
Kinds of blood cells: red blood cell - also called erythrocytes – carry oxygen from lungs to all tissues of the body. Each cell (there are 25 trillion in the average person) has hemoglobin - protein & iron that temporarily stores oxygen for delivery to cells. white blood cell - also called leukocytes, responsible for fighting infection and preventing cancer growth. Normally there are 4-11,000 in one drop of blood - but when sick they will increase. platelet - allows for blood clotting. They originate in bone marrow.
2. Heart - multi-chambered, muscular organ, responsible for overall flow of blood to tissues throughout the body.
3. Blood Vessels a. Capillaries - narrow microscopic vessels that carry blood between an artery and a vein, allowing for the exchange of substances between the blood and interstitial fluid.
b. Arteries - vessels that carry blood away from the heart to other parts of the body. c. Veins - vessels that return blood to the heart
Why does blood sometimes look blueunderneath the skin? Answer: Blood is always red.How dark a red depends on how much oxygen is inside it. The veins and such looks blue through our skin due to the absorption of light
Other facts: • In one minute all the blood in your body will have circulated. • Your body contains 5 liters of blood. • Blood removes waste products from the tissues and delivers them to the organs of the excretory system. • kidneyremoves nitrogenous wastes • liver removes many toxic compounds from the blood.