In Depth: Bones and Organs
The small intestine occupies the majority of the space of the abdominal cavity. This 21-foot long tube is where the bulk of digestion occurs. The small intestine breaks down fats, starches, and proteins into fatty acids, which can then be absorbed. The food you eat takes three to five hours to work its way through the small intestine.
Despite it’s misleading name, the large intestine is shorter (about five feet) than the small intestine, but it is larger in girth. It is the last part of the digestive tract and made up of the cecum, colon, and rectum.
At the height of the cavity is the liver, the body’s largest organ. It acts like a filtration system. It rids the body of toxins and produces bile to aid the process of metabolism, which is how food is broken down.
The gallbladder is a tiny sack near the liver that holds extra bile made by the liver until it is pumped into the small intestine. Bile helps break down fat.
Directly below the liver, the stomach stores food and prepares it for digestion. Digestive juices and stomach muscles churn the food to break it down further before it passes into the small intestine.
The pancreas is yet another gland that produces enzymes to help your body digest proteins, carbohydrates, and fats. It also makes hormones that help regulate the distribution of nutrients, including sugar.
Behind the intestines are the kidneys, important organs that contain an estimated 1 million filtering units called nephrons. The kidneys play a vital role in processing the blood the heart pumps before it goes into general circulation. Every minute, about 1,200 milliliters of blood flows through the kidneys, about one-fifth of all the blood pumped from the heart. Blood is pumped from the heart into the kidneys through the renal artery, which branches directly from the abdominal aorta, a section of the body’s main artery.
Directly on top of the kidneys are the suprarenal (adrenal) glands. Part of the endocrine system, these glands are divided into two portions, the adrenal cortex and the adrenal medulla, and each synthesizes and secretes a different set of hormones. The various hormones help the kidneys to conserve sodium, thus conserving water. They also play a role in supporting the body’s sexual functions, among other things.
The ureters are two tubes that carry urine from the kidneys to the urinary bladder. The ends of each tube act as valves by closing when the bladder is full and preventing backflow of urine.