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Student number: 600024293
Blood Transportation
The human circulatory system consists of blood, blood vessels and heart. The blood
is pumped by the heart continuously along a network of blood vessels to transport
substances around. Blood vessels are distributed throughout the whole body.
Therefore, the smallest vessels and the cells are only a short distance away from
each other. In human body, there are two types of circulatory system for the blood
transport. They are systemic circulation and pulmonary circulation.
Systemic circulation carries the oxygenated blood away from heart to body and
returns the deoxygenated blood back to the heart. The oxygenated blood goes
through the pulmonary veins from the lungs to the left atrium in heart. The left
ventricle pumps the blood to all parts of body through the aorta. The aorta carries
the blood to the head, arms, hands, chest, waist, legs and feet. When the blood flows
in the arteries, they deliver the blood to the arterioles and then to the capillaries. In
the capillaries, the bloodstream transports oxygen and nutrients, and picks up waste
materials between the blood and the cells. After that, the blood goes back through
the capillaries into venules, then to veins, and then to the vena cava. Blood from the
head and the arms goes back to the heart through the superior vena cava. Blood
from other parts of the body goes back through the inferior vena cava. These two
cava carry the deoxygenated blood back into the right atrium. The deoxygenated
blood enters to the right ventricle, and then pumps out the blood into the
pulmonary arteries.
Pulmonary circulation carries the blood to and from the lungs. The deoxygenated
blood pumps out from right ventricle to the lungs via pulmonary arteries. In the
lungs, the deoxygenated blood flows into the capillaries, and picks up the oxygen
and gives out the carbon dioxide. The blood flows slowly through the capillaries to
Student number: 600024293
allow more time for the gaseous exchange. The new oxygenated blood goes back to
the heart through pulmonary veins. The systemic circulation occurs.
http://lsa.colorado.edu/summarystreet/texts/heart.html
http://kidshealth.org/teen/your_body/body_basics/heart.html#
Pictures:
http://www.daviddarling.info/images/systemic_circuit.jpg
http://www.daviddarling.info/images/circulatory_system.jpg