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Blood: Top 10 Questions

January 2015

Thanks to Dr. Roger Turcotte, internist, St. Luke's Internal Medicine; and Dr. Alicia Lachiondo, pediatrician, Treasure Valley Pediatrics for the answers.

1: Why is blood so important in your body?

Blood has many functions. Blood is actually an organ just like other organs in your body such as your heart and liver. Its function is to circulate nutrients. It circulates oxygen, sugar and proteins, which you need in certain areas of your body, and gets rid of waste products, like carbon dioxide. (From Leah at Owyhee Harbor Elementary School in Boise)

2: How is blood made?

Blood is actually made in your bones. Some blood is made in your spine. Some is made in the big leg bone, called the femur and some in your long arm bones. Blood can also be made in your liver. And, a part of your blood is made in an organ called the thymus. (From Taylor at Owyhee Harbor Elementary School in Boise)

3: What substances make up blood?

Blood is made up of many different substances. There is plasma, which is a little over half of your blood's content. It is filled with sugar, proteins, and many other essential parts of your immune system. The other major component of your blood is composed of red blood cells. These cells carry oxygen to your tissues and also carry carbon dioxide. A smaller fraction of your blood content is made up of white blood cells. These cells fight infections and perform many other functions. The fourth component is made up of platelets, which help your body stop bleeding when you get cut. (From Colton at Kamiah Elementary School in Kamiah)

4: What happens when blood gets infected? What color does it turn?

When you have an infection, you can get really sick. Your blood will have a lot more white blood cells during the time of infection to help fight off the infection, but your blood will still be red because you will have a lot more red blood cells than white blood cells. (From Laurel at Cynthia Mann Elementary School in Boise)

5: How do you figure out the blood type of animals?

In any animal, including people, we use a blood sample to figure out blood type. Then, in a lab, we determine what blood type that person or animal has. Animals have different types of blood than people have. (From Haden at Owyhee Harbor Elementary School in Boise)

6: What is the difference between the types of blood?

There are four main types of blood that we consider to be important. They are: A, B, AB, and O. It is a bit complicated how we know this and make this distinction. Basically, on the surface of your red blood cells are proteins. We call these antigens. There is an A and a B antigen. People who have just the A antigen are type A, and people who have just the B antigen are type B. For people whose blood protein has both present, their blood is type AB. People who have neither protein present are type O. (From Steph at Owyhee Harbor Elementary School in Boise)

7: How does your blood pressure get too low or too high?

There are a lot of factors and many organs that affect your blood pressure. When we measure your blood pressure, we are measuring how much blood is pumping through your arteries and veins (little tubes that blood flows through), and how much pressure is inside those arteries and veins. We don't want the pressure to get too high or too low because it can affect the pressure in your organs. The most common way you can have low blood pressure is by being dehydrated because you are not drinking enough water. You can also have low blood pressure if you lose blood, like from a major injury. High blood pressure is more complicated. It is affected by salts that you eat, foods that you have eaten over the course of your life, how much you exercise, and how healthy your kidneys and other organs are. (From Cody at Kamiah Elementary School in Kamiah)

8: Do you always get your parents' blood type?

Your parents determine what your blood type will be, but you won't always have exactly the same type of blood as your parents. (From Abby at Owyhee Harbor Elementary School in Boise)

9: What happens to blood when we die?

When you die, your blood decomposes, just like your other tissues. When you are alive, blood has to be continuously replenished. That is, your body is continuously making blood. Red blood cells are destroyed in various places, usually in your spleen. A spleen is a special blood organ. As the red blood cells are destroyed, they have to be remade in your marrow, which is inside your bones. When you die, the production of red blood cells stops and your body simply decomposes. (From Izaih at Cynthia Mann Elementary School in Boise)

10: How does the heart pump blood?

The heart pumps blood by squeezing. Every time your heart squeezes, it squeezes blood out from the heart muscle to a great big blood vessel called the aorta, which then branches into many smaller vessels of your circulatory system. Each time your heart beats, it not only pumps blood out of your heart, but new blood comes from your lungs into your heart to be ready to pump out in that next cycle. (From Isabella at Owyhee Harbor Elementary School in Boise)

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