In this lesson, you’ll find out what tissues, organs, and glands are. You’ll also learn where each appears in the organization of the human body and get some examples of each. This lesson also defines histology and histologist.
Our bodies are very well organized, from the simplest, smallest part to the most complex. The hierarchy of our bodies goes like this: cell, tissue, organ, organ system, body. You’ve probably heard most, if not all, of these words before.
But did you know they’re actual medical terms?Let’s start by looking at the meaning of two of these words – tissues and organs – so you have a better idea of what they’re describing.
The first term we’re going to look at is tissues. We’re not talking about what you use to blow your nose. Instead, we’re referring to the tissues that help make up our bodies. Tissues are groups of organized cells all performing the same function.
You have different types of tissue throughout your body. Examples include adipose tissue, which primarily stores energy in the form of fat; epithelial tissue, which covers all surfaces of the body; and nervous tissue, which sends and receives informational signals throughout the body.
The next level up in the hierarchy is organs.
You might immediately think of the organ that you can play music on, but we’re talking about the organs in the human body. Although, without the organs of your body, you wouldn’t be able to play the musical organ. Organs are groups of organized tissues that serve the same function.When most people are asked to name parts of the body, organs are the first things that come to mind. They include the skin, kidneys, stomach, and brain, among other body structures.
Next, let’s discuss glands. Though not directly in the hierarchy of the body, glands could fit into a couple of places because they operate at the level of tissues and organs. A gland is specialized tissue or an organ that secretes chemical substances into the bloodstream or out of the body.
There are various categories of glands in the body. The main categories are endocrine, exocrine, paracrine, eccrine, and apocrine. Some examples of specific glands are sweat, thyroid, and pancreas. The largest gland in the body is the liver, though it’s also considered an organ.
Histology and Histologists
Next, let’s think back for a minute to when you first started learning about different word parts. One of the suffixes you might have learned is -logy, which means the study of. As your study broadened, you may have encountered the word root hist/o, which means tissue.
When you put these together, you should be able to determine that histology is the study of tissues.Histology involves the study of all the different types of tissues in the body. In the medical field, histology can be used to detect changes in tissues and help with diagnosis of various diseases, including cancer.Another suffix that you might have learned is -logist, which means a person who studies. Since we’ve already learned that hist/o means tissue, you’ve probably figured out that a histologist is a person who studies tissues.
A histologist also might study glands since glands are specialized tissues.
Let’s review. Tissues are groups of organized cells that work together to perform the same function. Some kinds of tissue are epithelial, nervous, and adipose. Organs are groups of organized tissues that serve the same function.
Examples include the brain, kidneys, skin, and stomach. Glands are specialized cells or organs that secrete chemical substances. The main categories of glands are endocrine, exocrine, paracrine, apocrine, and eccrine.
And, finally, histology is the study of tissue, while a histologist is a person who studies tissue.
When you are done, you should be able to:
- Describe tissues, organs, and glands
- Name some examples of tissues, organs, and glands
- Recall what histology is