Video Transcript
Which of the following is not a major type of tissue found in the human body? (A) Epithelial tissue, (B) connective tissue, (C) nervous tissue, (D) muscle tissue,
or (E) skeletal tissue.
The question deals with the major types of tissue in the human body, so let’s start
by defining this key term. A tissue is a group of cells that work together to perform a specific function. Looking at the levels of biological organization, we can see that tissues are
composed of cells and make up our organs. The types of cells found in a tissue determine the role it plays.
There are four main types of animal tissue. Epithelial tissue functions as a lining that covers and protects the internal and
external surfaces of our body. You can see an example of epithelial tissue right now, simply by taking a look at
your epidermis. That’s the outer layer of your skin, which serves as a physical defense against
foreign substances. Epithelial tissue also plays a role in absorption and secretion. For example, epithelial cells line the surface of our endocrine glands, such as the
pancreas, where they secrete hormones.
Connective tissue gets its name because it is found between other types of
tissues. For many of us, the connective tissues that first come to mind are tendons,
ligaments, and cartilage. However, this super diverse tissue is also found in blood, bones, and adipose tissue,
where it serves to attach, support, and bind to the other structures in the
body. A special feature of connective tissue is that it consists of living cells suspended
in a nonliving matrix. The specific cell types and the composition of the matrix give connective tissues
their various properties and allow them to perform their functions. For example, red and white blood cells are suspended in a liquid matrix called
plasma. This allows blood to flow through our blood vessels, performing gas and nutrient
exchange with our other tissues.
The main function of nervous tissue is communication. The nerves, brain, and spinal cord are composed of nervous tissue. They send and receive signals to and from the entire body. The brain has the additional role of processing these signals to help us react to our
ever-changing environment.
The fourth major type of animal tissue is muscle. There are three kinds of muscle tissues: cardiac, smooth, and skeletal. They all share the same basic function of producing movement, but they differ in
their specific function, their appearance, and where they are found in the body. For example, skeletal muscles are found attached to bones and are responsible for all
of our voluntary motions, meaning we can consciously decide to contract and relax
them.
Now let’s return to our question. We are asked to find the term that is not a major tissue type in the human body. We’ve seen that epithelial, connective, nervous, and muscle are all major tissue
types and that the term skeletal refers to a specific type of muscle tissue. It can also be used when talking about the skeleton, which is made of bones. We’ve learned that bones are actually a type of connective tissue.
So, the correct answer is (E). Skeletal tissue is not a tissue type found in the human body.
