Why do you need the intrinsic pathway when you have the extrinsic pathway?
Q. I understand that hemophilia is caused by factor VIII or IX deficiency and both factors work in the intrinsic pathway. (more…)
Q. I understand that hemophilia is caused by factor VIII or IX deficiency and both factors work in the intrinsic pathway. (more…)
Today we’ll continue on in our little series of posts on how to study for boards. In part I, we talked about how to set up a study plan, and how to pick among all the resources available for students. (more…)
Q. What does it mean when Robbins says the adrenal cortices are hyper- and hypoplastic?
A. Hypoplastic adrenal cortices mean that the adrenal cortices have atrophied; hyperplastic adrenal cortices mean that they have expanded. (more…)
I know a bunch of you are studying for boards, or are thinking about studying for boards. Any little memory aid that could help with a question or two is probably most welcome at this point.
Take, for example, all those cytokines with numbers (IL-1, IL-2…). How are you supposed to remember what all of those do?! Well, today’s post, written by a brilliant immunologist, gives you a great little method for remembering the interleukins associated with Th1 and Th2 cells.
1. Macrophages can produce IL-1 which activates Th cells (CD4 T cells).
2. If the macrophages also produce IL-12, this will drive the Th cells to become Th1 cells (2 to Th1, or “to” Th1).
3. If Th1 cells are induced, they will produce IL-2 (second cytokine in order) and both IL-3 and IFN-gamma (gamma is the 3rd letter of Greek alphabet and represents the 3, too). The IFN-gamma will activate cytotoxic T cells (CD8 T cells).
4. If the macrophages produce only IL-1, this will drive the Th cells to become Th2 cells. If Th2 cells are induced, they will produce IL-4, IL-5, and IL-6 (note that they follow in order) that drive B cells to divide and differentiate into plasma cells that produce antibody.
5. Th2 cells also produce IL-10 (“zero Th1”) which blocks macrophage production of IL-12 and thus blocks activation of Th1 cells.
Q. I have a question about the secretion of aldosterone that I haven’t been able to figure out by searching online or looking in books (maybe I’m looking in the wrong places!). (more…)
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