1.21. Cardiovascular System http://www.ck12.org
1.21 Cardiovascular System
- Describe the functions of the cardiovascular system.
What do you do for "cardio"?
"Cardio" has become slang for exercise that raises your heart rate. Cardio can include biking, running, or swimming.
Can you guess one of the main organs of the cardiovascular system? Yes, your heart.
Functions of the Cardiovascular System
Your cardiovascular system has many jobs. At times the cardiovascular system can work like a pump, a heating
system, or even a postal carrier. To do these tasks, your cardiovascular system works with other organ systems, such
as the respiratory, endocrine, and nervous systems.
Thecardiovascular system(Figure1.38) is made up of the heart, the blood vessels, and the blood. It moves nutri-
ents, gases (like oxygen), and wastes to and from your cells. Every cell in your body depends on your cardiovascular
system. If your cells don’t receive nutrients, they cannot survive. The main function of the cardiovascular system
is to deliver oxygen to each of your cells. Blood receives oxygen in your lungs and then is pumped, by your heart,
throughout your body. The oxygen then diffuses into your cells, and carbon dioxide, a waste product of cellular
respiration, moves from your cells into your blood to be delivered back to your lungs and exhaled. Each cell in your
body needs oxygen, as oxygen is used in cellular respiration to produce energy in the form of ATP.
The cardiovascular system also plays a role in maintaining body temperature. It helps to keep you warm by moving
warm blood around your body. Your blood vessels also control your body temperature to keep you from getting too
hot or too cold. When your brain senses that your body temperature is increasing, it sends messages to the blood
vessels in the skin to increase in diameter. Increasing the diameter of the blood vessels increases the amount of blood
and heat that moves near the skin’s surface. The heat is then released from the skin. This helps you cool down. What
do you think your blood vessels do when your body temperature is decreasing?