An accessory organ is a structure that assists the functionality of other organs in a system. The accessory organs of the abdomen include the liver, gallbladder, pancreas, spleen, adrenal glands, kidneys and the mesentery. The liver, gallbladder and pancreas are all accessory organs of digestion.
The liver is the largest organ in the abdominal cavity, and the largest gland in the human body. It is positioned in the right upper quadrant of the abdomen, and its functions include; bile synthesis, glycogen storage, clotting factor production and filtering the blood that it receives from the digestive tract before passing it to the rest of the body.
The gallbladder is located in the right hypochondrial region of the abdomen, just below the liver. It functions to concentrate and store bile that is produced by the liver, and release it during digestion.
The pancreas is an elongated organ located behind the stomach in the epigastrium. The head of the pancreas lies in the curve of the duodenum, and the tail lies near the spleen, in the left hypochondrium. The pancreas is an abdominal glandular organ with both digestive (exocrine) and hormonal (endocrine) functions.
The spleen is located in the left upper abdomen, and functions mainly as a blood filter and plays a role in both the cell-mediated and humoral immune responses.
The adrenal (suprarenal) glands are paired endocrine glands that sit above the kidneys. They secrete both steroid and catecholamine hormones directly into the blood.
The kidneys are bilateral organs located in the posterior abdomen. They function to filter and excrete waste products from the blood and to regulate the water and electrolyte balance in the body. The kidneys excrete the waste products as urine.
The abdominal mesentery is a double fold of peritoneal tissue that attaches organs, such as the small and large intestine, to the posterior abdominal wall. Blood vessels, nerves and lymphatics all run within the mesentery to supply the intestine.
In this section, learn more about the accessory organs of the abdomen- the liver, gallbladder, pancreas, spleen, adrenal glands, kidneys and the mesentery.
