The digestive system
The purpose of the digestive system is to break down food into components. The body can use glucose for energy, protein for building and repairing cells and extracting vitamins, minerals and amino acids a cell function.
The digestive system begins with the mouth where teeth mash food, the tongue moves it around and saliva lubricates there and begins digestion upon swallowing. Food travels down the esophagus and into the stomach where acid kills bacteria and breaks down food further. The liquid food then enters a small intestine where the acid is neutralized and enzymes break down fat, protein and carbohydrates for absorption by tiny hairs called villi. After traveling through 20 feet of small intestine through passes into the large intestine or colon where water is absorbed in bacteria very extract and manufacture important vitamins. A colon is around 5 feet long. The final stop is directon where in the adjustable food matter and gas are passed through the anus as feces and flatulence. The study of the digestive system is called Gastroenterology.
The Stomach is a muscular sac with hydrochloric acid to protect yourself from the acid. It has a mucous lining an adult stomach can hold not 0.5 gallons of food and liquid. There are nerves in the stomach that tell your brain when it’s empty or when it’s full vomiting is the body’s way of rejecting food and liquid that is bad for the stomach. The small intestine after leaving the stomach partially digested food called chyme enters the small intestine. The small intestine is 16 to 20 feet long in an adult human being. It’s called small because it is narrow about the thickness of your thumb. In the small intestine the gallbladder secretes gall to break down fats and the pancreas secretes insulin to manage blood sugar levels. Inside the small intestine millions of tiny hairs called villi increase the surface area so that nutrients can be absorbed into the bloodstream. Food moves along the intestine through like contractions called Peristalsis. The main job of the colon is to reabsorb most of this fluid so things move slowly. They can take 18 to 24 hours for food to leave your digestive system. The large intestine hosts billions of beneficial bacteria called gut flora or the microbiome. They manufacture and extract certain vitamins in fermentation by the gut. Bacteria creates gas. Fiber is very important for a healthy gut.
Diseases and Disorders of the colon include Irritable bowel syndrome and Colon cancer.
The immune system the human immune system is the military of the body it’s comprised of white blood cells and antibodies. These seek out and destroy foreign bodies including viruses, bacteria, parasites, fungi and abnormal cells. White blood cells are created in bone marrow and carried in the blood and lymphatic system. A single drop of blood can have 25,000 white blood cells. When white blood cells attack they envelope the pathogen and destroy it. The remains are carried away into the lymph system. The immune system is able to remember infections and fight them off better through antibodies. Vaccines work by stimulating the immune system to create antibodies for specific disease by polio or measles without actually getting it the person is then protected against that disease. It’s important to get vaccines even if the disease is no longer common because of the herd Immunity effect which is a form of immunity that occurs when the vaccination of a significant portion of a population or herd provides a measure of protection for individuals who have not developed immunity. Stress, smoking, lack of sleep, poor diet and diseases like HIV and AIDS can weaken the immune system making you vulnerable to infection, allergies and allergic reactions are false alarm and the result of an overactive immune system. Allergic reactions can cause anaphylactic shock and swelling where a person can’t breathe. Autoimmune diseases like lupus mean that the immune system attacks his own body and not just the germs.
Being too clean isn’t always a good thing without germs to develop antibodies the immune system doesn’t develop or learn what’s harmful and what’s not. The study of the immune system is called immunology.