In this video, we're going to begin our lesson on unicellular exocrine glands, more specifically, goblet cells. And so, of course, unicellular exocrine glands are going to be single-celled exocrine glands since recall that the root "uni" is a root that means 1. And so the most common unicellular exocrine gland is going to be the goblet cell. And so the goblet cell is named because its shape actually resembles that of a goblet or a wine glass if you will, and we'll be able to see that down below in our image. Now there actually is another notable unicellular exocrine gland and that is the mucus cell.

But really the mucus cell is effectively the same as the goblet cell. The biggest difference is that the mucus cell does not take on the shape of a goblet, whereas of course the goblet cells do take on the shape of a goblet. Now, these goblet cells are going to be found sprinkled in or dispersed in the epithelial tissue that lines the respiratory and intestinal tracts. And in fact, these goblet cells are going to be found in tissue that is usually shaped with columnar cells, long, tall, and narrow shaped cells. Now, these goblet cells are going to be secreting vesicles that are filled with a product called mucin, which is not to be confused with mucus.

Mucin is a glycoprotein that can ultimately form mucus, and mucus is going to be important for lubricating and protecting the epithelial tissue. Now, this mucin glycoprotein is going to be secreted by these goblet cells via exocytosis. And so, let's take a look at our example image down below where we can label the missing words on the diagram of the goblet cell. And so, once again, these goblet cells are going to be found sprinkled in or dispersed in the epithelial tissue that lines the respiratory tract and the intestinal tract. And so, notice that up above we have a micrograph from the respiratory tract and down below we have a micrograph from the intestinal tract.

And, what you'll notice is that both of these have some goblet cells sprinkled in the epithelial tissue lining those tracts. And so, notice that these goblet cells that are being indicated here, they actually take on the shape of a goblet or a wine glass, if you will. And so, if we do the outline here, you can see that a little bit more clearly. There's actually another goblet cell over here that we can trace. And then down below in the intestinal tracts, again, there are also these goblet cells and again, you can see their goblet shape or their wine glass shape right there.

And so over here, we actually have the goblet shape here. Again, it resembles that of a wine glass where it's wider at the top here and narrower toward the bottom. And then over here, what we have is yet another figure showing you the goblet cell here, embedded in that epithelial tissue lining of the respiratory and intestinal tract. And so notice that we're actually labeling the nucleus here of the goblet cell. You can see all of these other organelles of the goblet cell.

And we're also labeling these secretory vesicles that are again filled with mucin, the glycoprotein that ends up forming mucus. But again, mucin is not to be confused with mucus. And so we know that these secretory vesicles are going to be secreted by the goblet cell via exocytosis and then that mucin can ultimately form mucus. And so you can see the layer of mucus here in green, above the epithelial tissue. And again, this mucus is going to be important for lubricating and protecting the epithelial tissue.

Now, we're also labeling the microvilli of the goblet cell, which can be important for absorption. And so this here concludes our brief lesson on unicellular exocrine glands, more specifically, the goblet cells. And we'll be able to get some practice applying these concepts and learn more as we move forward. So I'll see you all in our next video. Oh, and I almost forgot, my goblet with a green drink in it.

Cheers. Delicious.