In this video, we're going to talk about the third commonly recognized characteristic of epithelial tissue, which is that epithelial tissue is a vascular but innervated. And so the term avascular is a term that means without blood vessels or no blood vessels. And so the opposite of a vascular is just vascular without the a and so the term vascular means with blood vessels. But again, epithelial tissue is avascular, meaning it has no blood vessels. Now, the term innervated means that it contains nerves or nervous tissue. And so once again, the epithelial tissue that we're highlighting here in our diagram is going to be avascular but innervated, meaning it has no blood vessels, but it does have nerves. And so notice that the nerves are highlighted in yellow here and notice that uh the nerves that are highlighted in yellow are actually extending into the epithelial tissue. And this is a big reason for why epithelial tissue is closely connected with the function of allowing sensation. Again, epithelial tissue in most cases is going to serve as a boundary but uh adjacent to open space. And so it is going to connect us to the outside world essentially, and it can detect the initial stimulus from the outside world such as touch or pressure or temperature. And upon detecting the initial stimulus, it can go on to activate these nerve endings that it is in close connection with. And so once these nerve endings are activated, they can transmit an electrical signal for processing, allowing for the full sensation. Now, another thing to notice here in this diagram is that the underlying connective tissue here is actually vascular and innervated. Notice that it does actually have blood vessels, but again, these blood vessels are in the connective tissue, the underlying connective tissue, they're not actually in the epithelia. Uh and also notice that it does have um uh nerves which is why it is innervated. But again, uh the nerves extend into the epithelial tissue, which is why the epithelial tissue is innervated. And so this year concludes our third characteristic of epithelial tissue. And we'll be able to talk about the fourth commonly recognized characteristic of epithelial tissue in our next video. So I'll see you all there.
