These structures’ +4 (“plus-4”) cells act as a reserve for replenishing the +1 (“plus-1”) to +3 (“plus-3”) base stem cells when necessary. For 10 points each:
[10h] Name these structures often used to model the stem cell niche. These structures’ lumens are isolated from digestive fluid by diffusion-limiting openings, regular CFTR-mediated flushing, and MUC2 secretion.
ANSWER: intestinal crypts [or colonic crypts; prompt on intestinal glands]
[10m] The stem cells at the bottom of intestinal crypts are maintained by these cells’ secretion of WNT ligands, Notch stimuli, and alpha-defensins. These cells rely heavily on glycolysis to generate lactate for stem cells’ use.
ANSWER: Paneth (“pah-neth”) cells [prompt on PCs; prompt on enterocytes]
[10e] Paneth cells’ position relative to intestinal stem cells influences the outcome of this general process, which occurs as stem cells migrate up the walls of a crypt. This process involves any stem cells becoming specialized.
ANSWER: differentiation [accept word forms]
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