Organ

Anatomy and Physiology of Organs

An organ is a group of tissues that perform a specific function or group of functions. They are usually composed of more than one cell type, arranged in a manner that allows them to act as a unit. Organs exist in most multicellular organisms, including not only humans and other animals but also plants.

Classification of Organs

Organs are classified primarily based on their associated systems, such as the digestive, respiratory, nervous, endocrine, cardiovascular, immune, urinary, muscular, skeletal, and reproductive systems.

Organ Systems

An organ system is a group of organs that work together to perform a complex overall function. For example, the digestive system, which includes organs such as the stomach and intestines, breaks down and absorbs food, while the respiratory system, which includes the lungs and bronchi, is responsible for breathing.

Organ Functions

The function of an organ is directly related to its structure. For example, the heart, a muscular organ, pumps blood through the body, while the brain, a complex organ composed of neurons, processes information and controls body functions.

Organ Development and Regeneration

The development of organs begins in the embryo with the formation of organ primordia from specific groups of cells. Some organs, like the liver, can regenerate to a significant extent after injury.

Organ Transplantation

Organ transplants are a common medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be transported from a donor site to another location.