viscera

Viscera are the soft internal organs of the body, especially those located within the thoracic and abdominal cavities. The term is the plural of viscus, meaning an internal organ, and is used to distinguish these structures from the body walls, bones, and connective tissues.

Thoracic viscera include the heart and lungs, while abdominal viscera comprise the stomach, intestines, liver, gallbladder, pancreas, spleen, kidneys (often considered retroperitoneal), adrenal glands, bladder, and, in females, the uterus and related structures. Many of these organs are intraperitoneal and suspended by mesenteries or ligaments, whereas others lie behind the peritoneum (retroperitoneal) or partially behind it.

Visceral organs are typically enveloped by serous membranes. For example, the visceral peritoneum covers abdominal organs, the visceral pleura covers the lungs, and the visceral pericardium covers the heart. These membranes reduce friction and help support organ movement within the cavities.

Innervation of the viscera is primarily autonomic, regulating function such as digestion, circulation, and excretion. Visceral pain is often poorly localized and may be referred to distant sites via autonomic pathways.

Etymology: viscus (plural viscera) derives from Latin, meaning an internal organ. In medical usage, viscera collectively refer to the internal organs contained within the major body cavities.