Human Organs

**Lungs** are the primary organs for breathing, responsible for gas exchange. The **trachea** funnels inhaled air to the lungs and directs exhaled air out of the body. The **heart** is a complex muscle that pumps blood through the three divisions of the circulatory system: coronary (vessels that serve the heart), pulmonary (between heart and lungs), and systemic (serving the body's systems). The **stomach** is a sac-like organ that secretes gastric digestive juices for digestion. The **pancreas** is a vital gland that secretes digestive enzymes. The **spleen** is the site where antigen-presenting cells (APCs) interacting with foreign particles in the blood can communicate with lymphocytes. The **gallbladder** is a small organ that aids the liver by storing bile and concentrating bile salts. The **kidneys** are a pair of bean-shaped structures located below and posterior to the liver within the peritoneal cavity. The **liver** produces bile, a digestive juice necessary for breaking down fatty components in the duodenum, processes vitamins and fats and synthesizes various plasma proteins. The **colon** hosts numerous bacteria that assist in digestion. The **small intestine** is the site where digestion of proteins, fats and carbohydrates is completed. *LICENSES AND ATTRIBUTIONS CC licensed content, Shared previously, Concepts of Biology, Authored by: OpenStax College. License: CC BY: Attribution. License Terms: Download for free at: http://cnx.org/contents/b3c1e1d2-839c-42b0-a314-e119a8aafbdd@8.39*