Have you ever thought about how amazing your blood is? All day and all night, it circulates through your body, delivering oxygen and electrolytes to your cells, removing carbon dioxide, and fighting infections.
How can blood do all that? Let’s take a closer look at the components in human blood, what they each do – and how your blood can help save lives.
What are the components of blood?
Blood has four main components: red cells, white cells, platelets and plasma. Red cells, white cells and platelets are made in our bone marrow. Combine them with liquid plasma, and you have blood. Simple, right? Yet each of these components has a unique and indispensable job to do in keeping us active, healthy and alive.
- Red blood cells transport precious cargo: oxygen
Red blood cells, carry oxygen from our lungs to the rest of our bodies. Then they make the return trip, taking carbon dioxide back to our lungs to be exhaled. They also give our blood its distinctive color – just two or three drops of blood can contain about one billion red blood cells.
- White blood cells fight bacteria and viruses
White blood cells help our bodies defend against disease by destroying harmful bacteria, creating antibodies against bacteria and viruses, and fighting malignant disease.
- Platelets control bleeding in our bodies
Platelets are small, colorless cell fragments in our blood that form clots and stop or prevent bleeding. This makes them essential to surviving surgeries such as organ transplant, as well as fighting cancer, chronic diseases, and traumatic injuries.
- Plasma is the liquid portion of blood
Plasma is about 92% water. It helps maintain blood pressure and volume, supplies critical proteins for blood clotting and immunity, carries electrolytes to our muscles, and helps maintain a proper pH balance in our bodies, which is necessary for cell function.
How are blood components used to help save lives?
Every two seconds, someone in the U.S. needs blood. Whether it’s a cancer patient or trauma victim, a newborn baby, someone receiving an organ transplant, or a person with sickle cell disease, the lifesaving blood they need can’t be created, engineered or manufactured – it must come from a generous donor.
- Red blood cells are the most commonly transfused blood component. Patients who need red blood cells include those with chronic anemia resulting from kidney failure or gastrointestinal bleeding, and those with acute blood loss resulting from trauma. They can also be used to treat blood disorders such as sickle cell disease.
- More than 50% of platelets are used in cancer treatment. Many cancer patients are unable to produce the platelets their bodies need because of the cancer treatments. Without a platelet transfusion, these cancer patients face life-threatening bleeding.
Platelets are also given to non-cancer patients who don’t have enough of their own, or when their platelets aren’t working correctly. Raising the patient’s blood platelet count reduces the risk of dangerous or even fatal bleeding.
- Donated plasma is commonly given to trauma, burn and shock patients, as well as people with severe liver disease or multiple clotting factor deficiencies. It helps with blood clotting, boosts the patient’s blood volume and can prevent shock. In addition, pharmaceutical companies use plasma to make treatments for conditions such as immune deficiencies and bleeding disorders.
What about white blood cells? Unfortunately, white blood cells can carry viruses that cause immune suppression and release toxic substances. To avoid these problems, white cells are often removed from donated blood before the donation is given to a patient.
How you (yes, you) can help save lives with your blood
At any time, 38% of people in the United States are eligible to donate blood. You might be one of them!
There are two main ways to donate red cells, platelets and plasma You can donate whole blood, which we separate into specific components that can be used to treat multiple patients.
Or, you can donate just one component at a time, through a process called apheresis. For example, if you want to donate platelets to help cancer patients, your blood will be drawn from your arm into a machine. There, the platelets are separated from the other blood components, which are returned to you through your other arm. This cycle repeats several times. Using this process, one donor can contribute as many platelets as would normally be obtained from up to five whole blood donations – an amount that can help as many as three people.
The American Red Cross always needs generous donors to supply red blood cells, platelets and plasma. Learn about the types of blood donations you can make and who they help.