Our question here says that on the line next to each cell type below, write an 'a' if that cell type contributes to absorption. Write an 's' if it contributes to secretion, and write an 'i' if it contributes to immune function. If the cell type contributes to none of these, write 'none'. Cells may contribute to more than one function. Alright, so let's take a look.
- Enterocytes: What do you think? Well, enterocytes, they line the small intestine. It's the most common cell type in the small intestine, in the epithelium of the small intestine, and they do absorption. So I'm going to put a big 'a' for absorption here.
- Enteroendocrine cells: Remember, 'entero' means gut and 'endocrine' refers to hormones. These cells make those paracrine molecules and hormones. So, I'm almost tempted to say 'none,' but they do secrete those signaling molecules. So I'm going to put an 's' here because what they're secreting are things like hormones.
- Goblet cells: What do you think about that? Well, goblet cells make the mucus that lines the small intestine. They secrete mucus, so I'm putting the 's' on the line.
- Mucosa associated lymphoid tissue: These cells we said are part of immune function. So I'm putting the 'i' on this line here.
- Paneth cells: Remember, 'p' was for protection. They are secreting some of those molecules that have antimicrobial agents. So that is immune function, but I said they're secreting those molecules. So I'm going to put an 's' for secretion and what they are secreting is molecules that have immune function. So I'm putting both 's' and 'i'.
- Stem cells: Well, stem cells divide to make all these other cells. So in terms of immune function, absorption, or secretion, they don't do any of them. They turn into cells that eventually do. So here I'm going to write 'none'.
Alright. Those are our cells of the intestinal epithelium for practice – after this, I'll see you there.