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Name: _____________________________________________ Period: ___________ Date: ______________________
Circulatory System
The circulatory system consists of the heart and blood vessels. The blood vessels are the arteries, veins, and
capillaries. A young person weighing about 100 pounds has about 7.5 pints of blood in his body. An adult man
has 6-7 qts. More than 12,000 qts. circulates through an adult in one day. Blood makes a complete trip
through the body in less than one minute.
Blood is manufactured in the bone marrow and goes through the body in veins through the right atrium, right
ventricle, then to the lungs for oxygen, back through the left atrium, left ventricle and out to the body in
arteries. Tiny thin-walled capillaries connect the veins and arteries. Valves are located in the heart between
each atrium and ventricle and between the ventricle and the artery from it so that the blood can go only one
way. The largest vessel leaving the heart is the aorta; the largest returning blood to the heart is the vena cava.
The right and left sides of heart are separated by a wall or septum. Both sides of the heart pump at the same
time, so we have one heartbeat. The heart has very strong muscles and its own blood supply. The heartbeat
or pulse rate varies from 100-120 times a minute in children to 70-90 times a minute in adults. The smaller
the heart, the greater the number of beats per minute. A mouse’s heartbeat is about 650 times per minute
while an elephant’s is about 35.
Using information from above complete the following:
1. Name the parts of the circulatory system:
a. ________________________________ c. ________________________________
b. ________________________________ d. ________________________________
2. Where is blood manufactured? _____________________________________________________________
3. How does the blood get from the arteries to the veins? __________________________________________
4. What keeps the blood flowing in one directions? _______________________________________________
5. How much greater in beats is the pulse rate of children than adults? _______________________________
6. The _____________________ the heart, the _______________________ the number of beats per minute.
Unscramble the words on the left and write them in the spaces on the right.
1. Carry blood to body
RTSEARIE
____________________________________
2. Carry blood to heart
ENIVS
____________________________________
3. Connects two vessels
LIAPLYCAR
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4. Where blood receives oxygen
NSUGL
____________________________________
5. Largest vessel leaving the heart
OTARA
____________________________________
6. Largest vessel returning blood
NEAV
to the heart
AVCA
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