Video Transcript
Which of the following best defines an organ system? Option (A) a group of different tissues that work together to perform a particular function. Option (B) a group of the same organs that work together to perform different functions. Option (C) a mass of cells that work together to perform multiple different functions. Option (D) a group of different organs that work together to perform a particular function. Or option (E) multiple, similar tissues that work together to carry out a particular function.
To answer this question, we need to know the meaning of the key terms organ system, tissues, organs, and cells. And we need to understand how they are linked in the organization of an organism.
So let’s start with cells. Cells are the fundamental units of living things. There are trillions of cells in the human body of about 200 different varieties. Each cell contains a nucleus, which contains the genetic information, and a variety of other organelles. Each cell is surrounded by a cell membrane. Groups of cells with a similar structure are organized into tissues. The cells and tissues all work together to carry out a particular function. Groups of different tissues working together to carry out a particular function form organs.
You may have started to recognize some of the structures in our example. The cells are epithelial cells, which line the inner surface of the small intestine. Groups of these cells work together to form the epithelial tissue. Epithelial tissue, along with other types of tissue, form the small intestine, an example of an organ. The specific role of the small intestine is the digestion of food and the absorption of nutrients.
The next level of organization is organ systems. Organ systems are made up of groups of organs all working together to carry out a particular function. In our example, the digestive system, the mouth, esophagus, stomach, pancreas, small intestine, large intestine, liver, and rectum all work together to digest food and absorb nutrients into the blood.
We now have enough information to answer our question. Which of the following best defines an organ system? We have just seen how an organ system is made up of a variety of different organs all working together to carry out a function. So the correct answer is (D), a group of different organs that work together to perform a particular function.
