Constantly Generating New Cells
The human body has amazing restorative properties in response to injury, or just the constant turning over of cells through the process of apoptosis. While we cannot grow a new arm if one is cut off in an accident, or a new pancreas if we destroy our beta cells by consuming too much sugar and becoming diabetic, we are essentially replacing ourselves all the time.
Shiny New Liver Cells
For example, your liver turns over to all new cells every six weeks. This is a good thing, since the liver is essentially a giant filter for the body. The liver filters blood coming from the digestive tract, detoxifies chemicals (such as alcohol), and metabolizes drugs (illegal and legal). It also secretes bile to help in digestion, and makes proteins used for blood clotting.
With so many jobs, the liver needs new cells frequently. The many jobs of the liver can lead to overuse and disease. For example, consuming too much alcohol over a long period of time can cause the liver to become scarred (cirrhosis) and no longer able to breakdown the alcohol into a safe form that can be excreted in the urine.
Sparkling Brand New Skin Cells
Your skin completely renews itself every 35 days. With exposure to the sun, chemicals, and other toxins in our environment, this is an important process since an in-tact epidermis is the first line of defense in the immune system. When this natural process of replacing skin cells happens too quickly, this is called psoriasis, which is generally thought to be an immune disease.
Stomach Lining Makeover
What about your stomach with all of that exposure to gastric acid? Well, you will be pleased to know that every 3-4 days the entire lining of the stomach is replaced. Frankly, if it didn’t do this, it would digest itself from all of the gastric acid it produces to begin the process of digestion of the foods we eat, as well as protect us from outside invaders like bacteria. In fact, stomach acid (hydrochloric acid) is so strong that it can dissolve metal and cement. No wonder gastric ulcers hurt so much!
A Normal Process
You’ve probably notices that those areas of the body that are most metabolically active are the areas where cells are dying and being replaced at the fastest pace. This is because metabolically active cells wear out the quickest, reaching the end of their working life sooner than less active cells, and thus need to be replaced more often.
In fact, some scientists estimate that the entire body is replaced every seven years because of the constant turnover of cells. Too bad I can’t replace it with a skinnier version of me. Keep in mind that because cells are dying and being replaced all the time, it’s not like you are constantly getting a brand-new kidney or liver. Rather, the cells themselves are being replaced a few at a time.
When Cells Don’t Die
I mentioned apoptosis earlier. Apoptosis is programmed cell death. Like I said, when cells get old, they need to retire and die. It’s part of the normal process of making sure that the body is composed of healthy, new cells.
However, sometimes the process of apoptosis doesn’t work, and cells no longer die according to programming. These are not normal cells, and this is what we call cancer.
When cells are exposed to chemicals, radiation, or even genetic factors, their pre-programmed cell death mechanism may be turned off. These cells continue to divide, and make new cells, which in turn make more cells. As these cells continue to pile on top of each other, a tumor forms. The tumor is simply an outgrowth of too many cells in one area. Microscopically we call this pleomorophism, or many cells.
Fascinated by How the Human Body Works?
If you are, then you should be a physician. Physicians not only understand how the body should work, but they understand what happens when it quits working properly. Or in other words, when disease strikes. They are also experts in addressing these diseases.
If this sounds like you, then why not join the UHSA family? We are the second oldest medical school in the Caribbean, and have been producing amazing doctors since 1982. With our help, you can join the ranks of graduates who practicing in the United States as well as all over the world; healing and helping.
To find out more, contact our Admissions Team today!