Dr Len Horovitz, a pulmonologist at Lenox Hill Hospital in New York City said, "Living with one lung doesn't usually affect everyday tasks or life expectancy, though a person with one lung wouldn't be able to exercise as strenuously as a healthy person with two lungs". When one lung is removed, the remaining lung inflates to take up some extra space.
Although humans have two kidneys, we need only one to survive. There are people born with just one kidney or have one removed after injury or for a donation. According to the National Kidney Foundation, most people live a healthy, normal lives with one kidney. People can live with no kidneys, but they require dialysis.
People remove their reproductive organs as a form of treatment for medical conditions. In cases like uterus cancer, uterine fibroids or chronic pelvic pain, women can have their uterus removed (hysterectomy). Men may have their testicles removed as a treatment for testicular cancer.
The whole stomach can be removed as a treatment for stomach cancer in a procedure called a total gastrectomy. In this procedure, the esophagus is connected to the small intestine. The small intestine acts like the stomach. The only problem is that the small intestine cannot absorb Vitamin B12 from food. Hence, a person without a stomach will have to be injected with vitamin B12 often.
People can also live without a colon but may need to wear a bag outside their body to collect stool. People may have their colon removed as a way to treat colon cancer or Crohn's disease, or in some cases, to prevent colon cancer. However, a surgical procedure can be performed to create a pouch in the small intestine that takes the place of the colon, and in this case, wearing a bag is not necessary.
The appendix is a tiny, worm-like shaped organ that protrudes out from the first part of the large intestine. Its function in the human body is unclear, hence it can be removed if it ruptures or becomes inflamed.
The spleen is not essential for survival, hence it can be removed when it's damaged. People without a spleen are prone to infections because its main function is to help the body fight infections.