Describe the primary functions and characteristics of epithelial tissue There are three principal cell shapes associated with epithelial cells: squamous. Epithelium is one of the four basic types of animal tissue, along with connective . types are squamous, cuboidal, and columnar classed by their shape. Some columnar cells are specialized for sensory reception. The other basic tissues are connective tissue, muscle tissue, and nervous tissue, There are three types of epithelia, each distinguished by the number of cell.
Kinds Three Epithelial There Are Basic Cells: Of
Take a quick look at the skin on your hands. Even if you think your skin is one smooth surface, it is actually made of millions of epithelial cells that are tightly packed next to each other. Epithelial cells also line the inside of your throat, intestines, blood vessels, and all your organs.
They are a barrier between the inside and outside of your body and are often the first place that is attacked by viruses as they begin their invasion deeper into the body. Epithelial cells are the safety shields of the body. Take another look at your hand. It is covered with epithelial cells that protect your body by being a barrier between your internal cells and the dirt and microbes in the environment. They also are able to stretch so you can move your fingers and arms into many positions.
You can also thank your epithelial cells for making the sweat that cools you down when you're exercising or when it's hot outside. To learn more about your skin and the important ways it works for you every day, listen to this podcast. Other epithelial cells help you experience your environment by having special sensors, called receptors, that collect signals. When you taste a favorite food or smell a flower, the receptors in these cells send the signal to your brain so you can enjoy every bite and sweet smell.
Once you swallow that bite of food, it travels down a path lined with epithelial cells. When it gets to your intestines, another set of epithelial cells absorbs and transports nutrients from the foods you eat and helps process it for energy your body can use.
Converting food energy to energy your body can use is the work of molecules called enzymes. Once again, it is epithelial cells that make and secrete the enzymes in your stomach. Epithelial cells also secrete hormones into your blood vessels, mucous in your nose and the breast milk which mothers feed their young.
If you take a close look at epithelial cells using a microscope, you will see them tightly packed together. This helps make a protective barrier for our bodies.
There are also some special door-like connections between each epithelial cell called gap junctions. The gap junctions are where the cells exchange nutrients.
Unfortunately, sometimes viruses can use these doors to spread between cells, too! Epithelial cells come in different shapes depending on where in the body they're found.
These shapes are called squamous, cuboidal, columnar and ciliated columnar. Squamous epithelial cells are flat and are usually found lining surfaces that require a smooth flow of fluid such as your blood vessels, or lining areas that require a very thin surface for molecules to pass through, such as the air sacs in your lungs. In addition to these shapes, epithelial cells can be described as being either simple or stratified. These terms refer to how many layers are present.
Simple tissue has only one layer of epithelial cells, while stratified tissue has many layers stacked on top of each other.
What happens is that nutrients will diffuse from the underlying tissue through the basement membrane to the epithelial cells.
And that's how epithelial cells get their nutrients. Let's just recap some of the places that you'd expect to find epithelial cells.
We already mentioned the outer layer of the skin, the tissue lining the mouth, esophagus and GI tract and of course this is not an exhaust of list.
In the tissue lining the kidney tubules, and the tissue lining blood and lymphatic vessels. And in fact the tissue that lines blood vessels and lymphatic vessels has a special name. It's known as endothelium. Let's talk about connective tissue. Connective tissue supports tissues, connects tissues and separates different types of tissues from each other and then there are different types of connective tissue that don't necessarily fall into these neat categories.
What are some examples of connective tissue? Bones, cartilage, blood, lymph, adipose tissue which is fat. The membranes covering the brain and the spinal cord and other types of tissues. What does connective tissue look like? What are some characteristics of connective tissue?
Basically it has three components. It has what's known as a ground substance and then it has fibers. The ground substance and the fibers together make up a matrix. Let's see what this looks like. Here we have the ground substance which is usually a viscous type of fluid. Then interspersed in the ground substance are fibers and then we have cells, and these cells are usually what is producing the matrix.
Let's look at some connective tissue in more detail. The first we'll talk about is areolar tissue which is this tissue right over here. Areolar tissue is a very common type of connective tissue. It binds together different types of tissue and it provides flexibility and cushioning, and we can actually see the structure pretty clearly in this picture. You can see the cells over there, those little dots. There's no cell over here. You can see the fibers running through it.
Over here and over here. And then the ground substance is the kind of background yellow, viscous liquid that you're seeing. Then we have adipose tissue. Adipose tissue is basically fat, tissue is a fat. It does not have fibers like most other connective tissue. Then we have what's called fibrous connective tissue. Fibrous connective tissue is pretty strong. It provides support and shock absorption for bones and organs, and you find it in the dermis which is the middle layer of the skin, tendons and ligaments.
Here are some more types of connective tissue. Blood is also an exception like adipose tissue and that it does not contain fibers. And the matrix of blood is the plasma and you can see the matrix, this yellowish liquid in which the blood cells are suspended. Then we have osseous tissue or bone tissue.
These cells in osseous tissue are known as osteocytes.
The cells in epithelia have different shapes, and different types of epithelia have different numbers of There are three main criteria for classifying epithelia. The three basic types of cell-to-cell junctions are tight junctions, gap junctions, they include additional types of cells interspersed among the epithelial cells. Epithelial cells (EC) are the first cell types to come into contact with external stimuli, cells are classified into three main cell groups according to their shape.