Video Transcript
What organ system is the stomach a
key component of?
This question asks us about a very
important organ within the body, the stomach. Let’s review biological
organization and then see how this works with the structure and function of the
stomach.
We are multicellular organisms made
up of trillions of cells. Most of these cells are
specialized. In other words, they have a
specific structure to carry out their role within the body. For example, muscle cells contain
special proteins which contract. And nerve cells have branches that
allow them to communicate with other cells. Specialized cells work together in
groups to carry out their functions. These groups of cells are known as
tissues.
If we look at the stomach, it has
internal linings composed of epithelial tissue, which, amongst other things,
protects the underlying tissues. It also has smooth muscle tissue
that contracts rhythmically to churn up the food. When these specialized tissues work
together to carry out specific roles within the body, they create an organ. This is how separate muscular,
epithelial, and connective tissues form the stomach. So let’s now take a quick look at
the roles of the stomach.
Did you know the stomach is only
about the size of your fist? However, it can expand to hold up
to four liters of food, which it then starts to digest. It can break down food in two
different ways: chemical and mechanical digestion.
It secretes enzymes for chemical
digestion, the main one being the protease enzyme pepsin, which breaks down proteins
into peptides and amino acids. Hydrochloric acid is also secreted
to kill bacteria that enter your stomach with the food and also to provide the
optimum pH for the pepsin to work at.
Mechanical digestion, on the other
hand, occurs when the muscles within the stomach contract to physically separate
food molecules.
We’ve seen how the tissues in the
stomach work as an organ, but if we look back at the question, we can see it is
asking about which organ system is the stomach a part of. So what is an organ system?
Groups of separate organs that work
with one another to conduct biological life processes are called organ systems. And the human body contains 11 of
them. You can imagine that the stomach is
pretty useless without the esophagus to carry food towards it. The stomach is also not very useful
without the small intestine to continue the digestion and then absorb the small,
soluble food molecules produced as a result.
As you can see, these organs rely
on one another to perform basic functions of the digestive system, like the
breakdown of food, absorption of nutrients, and egestion of feces. Without any one of these organs,
the digestive system would not function properly.
Other organ systems include the
skeletal system, respiratory system, and muscular system. Altogether, organ systems work
together to form a functional organism, in other words a living thing. Some of these systems heavily
depend on one another, like the circulatory system and respiratory system. And they are all required in order
to sustain life.
Now that we have reviewed the
stomach and how cells can be organized to form tissues, organs, and organ systems,
we can take a second look at our question. We are asked “What organ system is
the stomach a key component of?”. And we now know that it belongs to
the digestive system.
