Circulatory System

By:Claire H. Kiara S.and Jordan B.


The spleen is an organ found in almost all vertebrate animals. The spleen acts primarily as a blood filter. Life is indeed possible after the spleen is removed. Although people can live without a spleen, its absence can result in overwhelming bacterial infections if proper precautions are not taken. The spleen plays an important role in regard to red blood cells and the immune system. It remover old red blood cells and also recycles iron. In human and the spleen is brownish in colour and is located in the upper left portion of the abdomen. Infections that can affect the spleen are hepatitis,malaria, and brucellosis (rare bacterial, infection caused by ingestion of unsafe meat of milk).

Fast fact: Some people are born without a spleen and never no.

Blood Cells

Blood cells-red blood cells, white blood cells, platelets and capillaries. Together theses four kinds of blood cells add up to a total of 45% of the blood tissue by volume. The remaining 55% is made up of the liquid component of blood, plasma. Red blood cells carry oxygen and collect carbon dioxide,red blood cells have a life time of about 120 days, white blood cells are cells of the immune system, the help defend the body against disease.The main organ of this system is the heart.

Fast fact: Plasma carries red and white blood cells


Capillaries are thin and fragile. Capillaries are so thin that they are only one epithelial cell thick, and they are also so thin that the only way blood cells can go pass them is in a single file. Capillaries are also the smallest blood vessels. The capillary walls are so thin that they allow water, oxygen. carbon dioxide and other nutrients easily into your body.

Fast fact: the smallest capillaries are in the brain and intestines


The arteries are the blood vessels that gives oxygen blood to the tissues. Each artery is muscular tube lined by tissue. Your body is also like a highway , and the roads are arteries and veins. Pulmonary arteries carry blood from heart to the lungs where blood picks up oxygen. Systemic arteries give blood to the body. Did u know that the smallest artery is called the arterioles?

Fast fact: the main artery is called dorsal aorta.


Veins are not as strong as arteries. Inside veins are flaps that let blood flow to go in one direction. Veins must be able to not let blood to start backing up. Veins must be able to allow blood to get together without bursting. Veins have valves to prevent blood to go backwards. Veins have less muscle and tissue than arteries they don’t always keep their tube shape and they could appear flattened. Varicose veins lead to stress or aching of the part where they are.

Fast fact: The walls of the veins are really thin and the rich blood is visible through the skin.


It takes blood 20 seconds to go throughout the body. The adult heart beats 72 times per min, 100,000 times per day, 3,600,000 times per year, and 2.5 billion times in a lifetime. When you hear the heart go "thump thump" that is the heart closing. A woman's heart beats faster than a man's. If you squeeze a tennis ball tightly enough, that's how hard your heart beats. A man's heart beats 70 times per minute, and a woman's heart beats 78 times per minute. Your heart beats about 3 billion times throughout a lifetime.

Fast fact : Daily, the heart creates enough energy to make a truck drive 20 miles !