BR cbt1 BS#119

[dougkaye]

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BR's key is saying that theca cells secrete estrogen to build up and maintain endometrium (EM). This is not true. Granulosa cells of developing follicle (and then corp luteum) secrete estrogen. It's not a big deal, but they are asking some very detailed questions and so it's important to get the facts straight.

According to my bio book, which I trust: "During the preovulatory phase, FSH stimulates a few follicles to begin to develop, and stimulates the granulosa cells to multiply and produce estrogen." Authors then continue to say that the theca cells produce androgens which are then converted to estrogen by the granulosa cells. So theca cells don't secrete estrogen as the key states for #119. I have found that AAMC rarely goes into this much detail but then again they like to throw in random factoids.

(Biology, 6th Edition, Solomon, Berg, Martin)

 

[dougkaye]

removed

 

[attixx]

Here is verbatim from EK:

"FSH stimulates the growth of granulosa cells around the primary oocyte. The granulosa cells secrete a viscous substance around the egg called the zona pellucida. The structure at this stage is called the primary follicle. Next, theca cells differentiate from the interstitial tissue, and grow around the follicle to form a secondary follicle. Upon stimulation by LH, theca cells secrete androgen, which is converted to estradiol (a type of estrogen) by the granulosa cells in the presence of FSH and secreted into the blood."

This indicates that theca cells actually do the secreting of the androgen, but FSH/granulosa cells cause the conversion into estradiol.

Your bio book is right in saying the granulosa cells produce estrogen, but produce in this case does not mean secrete.

 

[dougkaye]

Here is verbatim from EK:

"FSH stimulates the growth of granulosa cells around the primary oocyte. The granulosa cells secrete a viscous substance around the egg called the zona pellucida. The structure at this stage is called the primary follicle. Next, theca cells differentiate from the interstitial tissue, and grow around the follicle to form a secondary follicle. Upon stimulation by LH, theca cells secrete androgen, which is converted to estradiol (a type of estrogen) by the granulosa cells in the presence of FSH and secreted into the blood."

This indicates that theca cells actually do the secreting of the androgen, but FSH/granulosa cells cause the conversion into estradiol.

Your bio book is right in saying the granulosa cells produce estrogen, but produce in this case does not mean secrete.

Good points. But the original problem is that BR (both in their CBT and books) says that estrogen is directly secreted by theca cells but that's not the case as both of us pointed out. Secreting an androgen or any other precursor is definitely NOT the same as secreting the actual product, which is exactly what the granulosa cells do. Just something for BR to clean up on their next iteration. I love their materials but I also like to point out inconsistencies in diagnostics especially.