organ
After tissues, organs are the next level of organization of the human body. An organ is a structure that consists of two or more types of tissues that work together to do the same job. Examples of human organs include the brain, heart, lungs, skin, and kidneys. Human organs are organized into organ systems, many of which are shown in Figure below . An organ system is a group of organs that work together to carry out a complex overall function. Each organ of the system does part of the larger job.