all right let's talk about how we actually produce the thyroid hormone so first of all the the thyroid hormone is produced it's built in the colloid but the follicle cells themselves have an important job and their first job and see we can get this to work is to produce a substance called thyroglobulin so thyroid globulin is produced inside the cells and basically what I'm going to draw you a picture of it because essentially thyroid globulin is the amino acid tyrosine I don't know if you remember that thyroid hormone is an amino acid derivative and essentially it's thyroid globulin is 70 tear scene molecules and tear scene is just an amino acid in sequence do you think I'm going to draw 70 of them are you afraid okay I'll stop once thyroid globulin is produced in the follicle cell it's exocytosed out into the colloid so that works like now we have it in the colloid now the second thing that happens in the follicle cell is that iodine iodine is transported into the colloid and so here's the scoop there is a little transporter I'm going to do this in another cell I'll do this one up here there's an iodine transporter that transports I don't know if you remember all my color coding sodium and iodine into the follicle cell and and that's a symporter and so that they're working together but the sodium is pumped down its concentration gradient and it allows iodine to come along with it now on the luminal edge had to think about that for a second because this would be the luminal edge of the follicle so there's another guy that transports iodine in and this guy's name is pend Hren and I'm telling you this because I think there are clip there's clinical significance to a malfunctioning Pendred because you can't get your iodine into the colloid okay so once iodine is in and thyroglobulin is in the iodine's are added to the thyroid thyroid globulin so remember that each box was just a tea racine amino acid so basically they get iya dated you know if that's word iodized that's what they get and they get iodized with either one or two and and iodine is added to them now here's the scoop and I want you to visualize this for a second the fact is that this thyroid globulin is really it's really long and it makes this kind of messy tangle okay and I'm gonna try to make it so that I can do what I want to do because the next thing that happens after the thyroid globulin gets iya dated I mean iodized then watch a place that has one iodine forms a bond with a place that has two iodine's and look whoa bad hate it when it does that it makes those random circles it forms a bond like right here now do you see that so watch I'm going to make a little circle around this so that you can see this right here that is one flavor of thyroid hormone it's t3 thyroid hormone ultimately eight or combined with a one-er and made a 3r we can also have a 4 T 4 and T 4 happens let's see if I can make one there's a tour and here's a tour and then they combine with each other did you follow that and now we have another thyroid hormone that's t4 I just showed you that because I had a really hard time visualizing how the the the thyroid globulin pieces that had to iodine's connected to the ones that had one iodine to make t3 and t4 t3 and t4 are your thyroid hormones so watch after you ayah date iodized the thyroid globulin then you fold and combine your 3s in your ones your twos in your ones it's equal threes and fours and then you I've got to put it down here endocytosed that says endocytosed what are you gonna end us i toast my friends how about let's just take this whole folded thyroglobulin thing and endocytosis it into the follicle cell once it's in the follicle cell part 6 you have an enzyme that slices it up so you had thyroglobulin in the follicle cell exocytosis it add iodine's fold endocytosis the whole thing in the follicle cell and then chop it up chop up the hormones and you get t3 and t4 t3 and t4 and again you you're chopping all of these things up and then you exocytosed the t3 and t4 into the bloodstream does that work for you you can store oh gosh I read it somewhere how much you could store like week's worth of thyroid hormone in a single follicle in the colloid so you basically only endocytosed this step when you need thyroid hormone otherwise just leave it in the colloid and save it for later all right let's talk about what thyroid hormone does