The organs that are present within the abdomen are called abdominal organs. Many important viscera of the body are located in the abdomen that performs many important functions. The abdomen consists of the abdominal cavity that is located between the thoracic and pelvic cavity. The abdominal cavity is separated from the thoracic cavity by the diaphragm and is separated from the pelvic cavity by the pelvic inlet.
The organs that are present in the abdomen are stomach, liver, gallbladder, spleen, pancreas, small intestine, large intestine, appendix, and adrenal glands. The main blood vessels are also present in the abdomen such as the abdominal aorta, and inferior vena cava.
There are also many organs that can be either seen as abdominal or pelvic organs, for example, urinary bladder, uterus, fallopian tube, and ovaries. But here we will not include these organs in the abdominal organs.
Important abdominal organs
The stomach is a hollow organ and a dilated structure that functions as a vital digestive organ. In anatomy, the stomach is divided into four parts that are the cardia, fundus, body, and pylorus. The stomach has two curvatures that are the lesser curvature and the greater curvature. The cardiac region and the lesser curvature of the stomach is supplied by the right and left gastric artery. The greater curvature of the stomach is supplied by the right and left gastroepiploic artery. The fundus is supplied by the short gastric artery. The walls of the stomach consist of many layers that are the 1. mucosa, 2. inner mucosa, 3. muscularis externa, 4. and serosa. The functions of the stomach are the release of proteins digesting enzymes and hydrochloric acids. The stomach also churned the food through muscular contraction.
The liver is present in the right upper quadrant of the abdomen and its functions are to detoxify various metabolites, synthesizes proteins, and produce biochemicals that are necessary for digestion. The liver also plays a major role in glycogen storage, decomposition of red blood cells, and the production of hormones. The liver produces bile that helps in the breakdown of the fats. In anatomy, the liver is divided into four lobes that are the right lobe, the left lobe, the quadate lobe, and the quadrate lobe. The functional unit of the liver is lobules that contain million of hepatic cells called hepatocytes.
3. Gall bladder
The gall bladder is a small hollow organ where bile that is produced in the liver is stored and concentrated before its release. The gall bladder sits in a shallow depression below the right lobe. In anatomy, the gall bladder is divided into three sections that are the fundus, body, and neck. Its main function is to store bile and concentrate them and releases it when needed.
The spleen is an organ that is similar in structure to a large lymph node and it plays an important role in regard to red blood cells and the immune system. The spleen mainly acts as a blood filter. In anatomy, the spleen is divided into two regions that are an anterior gastric portion, and the posterior renal portion. The two main structures that are present in the spleen are the red pulp and the white pulp. During prenatal development, the spleen produces all types of blood cells.
The pancreas is an organ of both the digestive system and the endocrine system. It is located behind the stomach. In anatomy, the pancreas is divided into the head, body, neck, and tail. The body is the longest part of the pancreas. The pancreas contains tissue some of which play endocrine and some play an exocrine role. The tissues which play an endocrine role are called islets of Langerhans that contains alpha, beta, delta, and PP cells. The tissues that play an exocrine role are called acini.
6. Small intestine
The small intestine is an organ in the GIT where many important substances present in the food such as nutrients and minerals are absorbed from the food. The small intestine receives the bile and pancreatic juice that helps in the breakdown of fats, proteins, and carbohydrates. In anatomy, the small intestine is divided into three regions that are duodenum, jejunum, and the ileum. The duodenum receives its blood supply from the superior and inferior pancreaticoduodenal arteries while the jejunum and ileum receives its blood supply from the superior mesenteric artery. The walls of the small intestine consist of mucosa, submucosa, muscularis externa, and externa.
The kidneys are bean-shaped organs that perform many important functions in the body and are located in the retroperitoneal space. Kidneys are 11 cm in length and receive their blood supply from the renal arteries. Each kidney s attached to the ureter that carries urine formed in the kidney to another structure called the urinary bladder. Kidneys are made of structural and functional units called nephron. About one million nephrons are present in each kidney. Each kidney is divided into two structures that are the renal cortex and the renal medulla. The main functions of the kidneys are to excrete various waste products into the urine, regulate the water balance in the body, and regulate the acid balance in the body. Kidneys perform these functions through the formation of urine. The formation of urine occurs in the four steps that are filtration, reabsorption, secretion, and excretion.
8. Large intestine
The large intestine is the last part of the GIT where water is absorbed and the waste material is stored as feces. In anatomy the large intestine is divided into caecum, ascending colon, descending colon, transverse colon, sigmoid colon, and rectum. The large intestine extracts the water and salt from the waste. The large intestine does not play a role in the absorption of nutrients and minerals. The large intestine receives its blood supply from the superior and inferior mesenteric arteries.
9. Adrenal gland
The adrenal glands are the endocrine glands that produce the adrenalin, aldosterone, and cortisol. They are located above the kidneys. In anatomy, the adrenal glands are divided into two regions that are outer cortex and the inner medulla. The cortex is then divided into three regions that are the zona glomerulosa, fasculita, and retuclaris. The cortex produces mineralocorticoids, glucocorticoids, and androgens.
The appendix is a small sac of tissue that is present in the lower right abdomen. It is also called the vermiform appendix. It is located in the caecum. The appendix is about 4 inches long and its function is unknown. Some anatomists and physiologists believe that the appendix act as a storehouse for good bacteria.