If you’re reading this, you most likely already know a bit about blood components.
But do you know why red blood cells don’t live longer than 4 months? Or why your doctor might get worried if you have more white blood cells than normal? Or even what exactly plasma does for your body?
Blood is vital in our body if you didn’t already know that, and knowing more about it means knowing more about yourself.
If you want to continue to learn about your blood and blood donation check out my book The Blood Donor Handbook: A Guide to Blood Donation and Its Benefits.
An Overview
The average volume of blood present in a human body ranges from 5.6 liters for adult males to 4.5 liters for adult females.10 While a smaller human, such as a newborn baby will have around 1 cup of blood in its entire body upon birth.10 To put this in perspective, 1 cup equals 8 ounces, meaning one glass from your kitchen could hold the full volume of blood from a newborn. A disturbing thought, but it is an accurate one.
Blood carries needed material throughout our body including electrolytes, hormones, vitamins, antibodies, heat, oxygen, and cells that fight infection. While blood carries things to different parts of your body, it also carries things away such as carbon dioxide and waste matter, making it the transportation system in your body.
The Most Intricate Roadmap in the World
Think of the blood vessels in your body as the roadmap of your state. The two main arteries and two main veins are the big interstates that everyone travels on at some point in their lives. The interstates don’t take you directly to your destination though, you rely on smaller highways, roads, streets, alleys, and even your own driveway to get from one place to another. And like the roads, so does your blood rely on the major arteries and veins breaking down into smaller vessels and then even smaller into capillaries to reach their destinations.
The road map of your blood vessels breaks down so small that it would take 10 of your smallest capillaries to equal the size of a single strand of your hair. This means that to get through these really narrow capillaries, your cells sometimes have to go one at a time. On top of that, you have so many of these small pathways throughout your body. If you were to take every single blood vessel, from your major ones to the microscopic ones, and lay them end to end, they would span about 60,000 miles. That means all of the blood vessels in your body could make it around the Earth TWICE with some to spare.
When you scrape your knee or get a paper cut the blood that you see is made up of four main components; red blood cells, white blood cells, platelets, and plasma. Each of these components has vastly different jobs within the body and to understand why they are important let’s take a look at what they all do.
Red Blood Cells
As their name suggests, these are the cells that give your blood its signature red color. Your blood is made up of about 40% to 45% red blood cells and they are extremely important! But these cells only last about 120 days (4 months) before dying because they don’t have a nucleus.5
Their lack of a nucleus, while shortening their lifespan, actually allows them to be more flexible and move through the narrow blood capillaries with ease. Their lack of a nucleus also allows them to be made smaller than the average cell and on average red blood cells are around 7 microns in size.10 That’s about a third the diameter of a human hair! Because of their short lifespan, your body has to create new red blood cells constantly, around 17 million red blood cells per second. If an outside factor causes stress, the body can respond by producing up to 7 times that amount.10 That’s up to 119 million red blood cells per second!
Red blood cells have a very big job in the body. They carry oxygen into your body and carbon dioxide out of your body which allows your muscles to function how they are meant to.5 This allows your brain to function, your heart to beat, and keeps you healthy, and alive. There’s a protein called hemoglobin in red blood cells that allows these cells to carry oxygen and carbon dioxide to and from your body. Hemoglobin is composed mainly of iron. This is why an iron supplement is suggested when you have low hemoglobin. The combination of iron and oxygen gives red blood cells, and blood, its red color. When you go to donate blood, this is one of the things checked prior to clearing you for blood donation.
White Blood Cells
When your body is fighting an infection, these are the cells sent to fight off the invaders. There are five different kinds of white blood cells, basophils, neutrophils, eosinophils, lymphocytes, and monocytes.5 Each of these types helps with specific types of infections including bacterial, viral, fungal, and parasitic infections.
Mutated cells such as cancer are also taken care of by white blood cells. They’re also the cells that decide your allergens (if you have any) and the “fighting” that occurs between your white blood cells and the food you are allergic to is known as an allergic reaction.
Other than taking care of cells that aren’t natural such as those that cause infection, white blood cells also assist in the healing process. They do this by ingesting debris from tissue and dead cells as well as old red blood cells.5 Therefore having a high white blood cells count is synonymous with having an infection or disease of some kind.
Platelets
Stopping a bleed is incredibly important and this function falls to the platelets in your body. Platelets are small cells that clump together forming clots that plug up the opening in your skin.5
This ability of the body to heal itself is essential in surviving surgeries and conditions such as fighting cancer and chronic or traumatic injuries. If you have blood work done and notice a low platelet count, this can be indicative of cancer or other health problems.
Plasma
Plasma shoulders a lot of the work in our bodies. It’s a liquid that consists mostly of water, which doesn’t make it sound very special, but plasma has several important functions; this includes regulating body temperature and pH.5
If blood cells such as red blood cells, white blood cells, and platelets are workers in your body, your plasma is their transportation and material. Blood plasma carries all of the aforementioned cells throughout your body and consists of hormones, glucose, proteins, gasses, electrolytes, and nutrients.5 All of these things assist your cells, and your body, in running smoothly and efficiently.
Just as plasma carries much-needed nutrients to different parts of the body, it also carries waste away from the body so that it can be disposed of and excreted.
Resources
1 Akinlusi, F. M., Rabiu, K. A., Durojaiye, I. A., Adewunmi, A. A., Ottun, T. A., & Oshodi, Y. A. (2018, January 10). Cesarean delivery-related blood transfusion: correlates in a tertiary hospital in Southwest Nigeria. BMC Pregnancy and Childbirth. Retrieved December 19, 2021, from https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/s12884-017-1643-7
2 American National Red Cross. (2021). Platelets and Thrombocytopenia. American Red Cross Blood Services. Retrieved December 19, 2021, from https://www.redcrossblood.org/donate-blood/dlp/platelet-information.html#:~:text=Platelets%20control%20bleeding%20in%20our,chronic%20diseases%2C%20and%20traumatic%20injuries
3 American National Red Cross. (2021). What Happens to Donated Blood. American Red Cross Blood Services. Retrieved December 19, 2021, from https://www.redcrossblood.org/donate-blood/blood-donation-process/what-happens-to-donated-blood.html
4 American Red Cross. (2019, November 22). Why CMV negative blood is so important. American Red Cross Blood Services. Retrieved December 19, 2021, from https://www.redcrossblood.org/local-homepage/news/article/why-cmv-negative-blood-is-so-important.html
5 American Society of Hematology. (2021). Blood Basics. American Society of Hematology. Retrieved December 19, 2021, from https://www.hematology.org/education/patients/blood-basics
6 Australian Red Cross Lifeblood. (2021). James Harrison’s story. Australian Red Cross Lifeblood. Retrieved December 19, 2021, from https://www.lifeblood.com.au/news-and-stories/stories/james-harrison
7 Cho, M. S., Modi, P., & Sharma, S. (2021, July 26). Transfusion-related Acute Lung Injury. National Center for Biotechnology Information. Retrieved December 19, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK507846/
8 Cirino, E. (2017, March 14). The Disadvantages of Donating Blood. Healthline Media. Retrieved December 19, 2021, from https://www.healthline.com/health/disadvantages-blood-donation#the-pros
9 Cleveland Clinic. (2021). Function of Red Blood Cells. Cleveland Clinic. Retrieved December 19, 2021, from https://my.clevelandclinic.org/health/body/21691-function-of-red-blood-cells
10 Community Blood Center. (2021). Blood Fun Facts. Community Blood Center of the Ozarks. Retrieved December 19, 2021, from https://www.cbco.org/blood-fun-facts/
11 George, R. (2019, May 14). The Intersection of Race and Blood. The New York Times. Retrieved December 19, 2021, from https://www.nytimes.com/2019/05/14/well/live/blood-type-race-racial.html
12 Palmieri, T. L. (2021, January 12). Transfusion and Infections in the Burn Patient. Mary Ann Liebert Inc. Retrieved December 19, 2021, from https://www.liebertpub.com/doi/abs/10.1089/sur.2020.160?journalCode=sur#:~:text=The%20majority%20of%20burn%20transfusions,during%20their%20hospitalization%20%5B10%5D
13 Toy, P., & Lowell, C. (2007, January 6). TRALI – Definition, mechanisms, incidence and clinical relevance. National Center for Biotechnology information. Retrieved December 19, 2021, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2767181/14 Yeh, T., Shelton, L., & Yeh, T. J. (1978, July 26). Blood loss and bank blood requirement in coronary bypass surgery. PubMed. Retrieved December 19, 2021, from https://pubmed.ncbi.nlm.nih.gov/307370/
