Thyroid The thyroid is responsible for producing hormones that regulate the body\u2019s metabolism and important bodily functions that depend on hormones such as the female reproductive cycle. Modern medicine has made it possible to live without the thyroid gland or live with a dysfunctional one, as synthetic hormones that replicate those that would be produced by the thyroid can be manufactured and introduced to the body as substitutes. Many people today live off the synthetic hormones. Tonsils Tonsils work by catching germs that enter the body through the mouth and alerting the body to produce white blood cells. But since they are a small part of the lymphatic system, they can easily be removed without causing a person to experience any health issues. Most people who often get tonsillitis have them surgically removed to prevent the painful bouts that characterise tonsillitis. Stomach While some people live to eat, it is possible to lead a normal life without a stomach. The stomach\u2019s main functions are storing and breaking down food to gradually pass it on to the intestines. In the absence of a stomach, surgeons attach the gullet to the small intestines. Food consumed in small quantities can move directly from the gullet to the small intestine and still be digested. With a good recovery post-surgery, one can eat a normal diet alongside vitamin supplements. Bladder The bladder is a very important organ in the urinary tract whose main function is to store urine before it is passed out of the body. The bladder can be surgically removed from the body if it\u2019s cancerous or presents inflammatory disorders in a person. Once removed, one may need to wear a special bag attached to the outside of their abdomen in order to remove their urine in a procedure called a urostomy where urine is allowed to drain constantly from the body. At times, doctors may create a pouch using tissue from the intestine that can hold urine after it passes through the kidneys. The urine is then drained from the pouch using a catheter. Colon The colon, also called the large intestine, is a tube located between the stomach and the small intestines with the primary function of reabsorbing water from digested food and preparing faeces by compacting it together. When cancerous cells are found in the colon, part or all of the six-inch tube has to be removed. One can lead a normal life after the removal of the colon despite a small change in diet and bowel movements. Kidneys While you might know that humans can live a full life with just one kidney instead of two, one can still live without both kidneys but with the help of regular dialysis. The main job of the kidney is to filter blood to remove waste. This role is taken over by a machine or an induced chemical through dialysis. Though the process is expensive, one can lead a long normal life post-surgery even without a single kidney. Spleen The spleen is most commonly removed as a result of injury as it sits close to the ribs and next to the stomach and is, therefore vulnerable to abdominal trauma. It is enclosed by a tissue paper-like capsule, which easily tears, allowing blood to leak from the damaged spleen. If not diagnosed and treated or removed, the bleeding can result in death. The spleen\u2019s main functions are the storing and recycling of red blood cells, white blood cells and platelets. Upon its removal, the liver and the lymphatic system easily take over these functions. Appendix Initially thought to be vestigial, scientists say that the appendix is a store for the good bowel bacteria enabling them to repopulate when need be. The appendix can be removed and the person continues to lead a perfectly normal life. It is commonly removed when someone suffers from appendicitis. This is when the appendix becomes full of intestinal contents and becomes painfully inflamed. It can rupture if not removed in time. Gall bladder The gallbladder is a small sac-shaped organ that stores bile juice, which is a digestive enzyme that helps the body digest fatty foods. Sometimes, gallstones form in the gall bladder. If they become too large or too frequent, the entire gall bladder has to be surgically removed and the person goes on to lead a normal life. They however have to be careful about eating high fat foods as they may experience digestive issues after. Reproductive organs One can live comfortably after the removal of the uterus and testicles, the female and male reproductive organs, respectively. The only effect is that one cannot beget an heir post-surgery, unless they had stored eggs and sperm cells and have enough money to do in-vitro fertilisation and hire a surrogate mother. Research suggests that hysterectomy has no effect on women\u2019s life expectancy. Interestingly, in some male populations, removal of both testicles may lead to an increase in life expectancy.