TBR CBT 1: Endometrium Lining

[LuminousTruth]

From Figure 1, determine which hormone(s) and structures are responsible for the increase in thickness of the endometrial lining of the uterus.

A. Estrogen, progesterone, and the thecal cells of the developing follicle
B. Estrogen and the thecal cells of the developing follicle
C. Progesterone and the luteal cells of the corpus luteum
D. Progesterone, estrogen, and the luteal cells of the corpus luteum

From figure 1, it was shown that estrogen and progesterone rises as the endometrial lining thickens. Therefore, I thought it was D because after ovulation, the corpus luteum secretes estrogen and progesterone.

However, the answer was "A"

Can someone explain why it was not D?

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[regeneration]

Bit confused as to what you're saying is the right answer. I would put A because the endometrial lining of the uterus thickens and "proliferates" during the follicular phase (or proliferative phase); this is the phase in which follicles develop as well, and estrogen + progesterone are released.

 

[LuminousTruth]

Bit confused as to what you're saying is the right answer. I would put A because the endometrial lining of the uterus thickens and "proliferates" during the follicular phase (or proliferative phase); this is the phase in which follicles develop as well, and estrogen + progesterone are released.

Whoops, my bad. I meant - how is the answer not D? I thought the endometrial lining thickens due to the estrogen and progesterone secreted by the corpus luteum. Do both the corpus luteum and thecal cells contribute to the lining or JUST thecal cells?

 

[LookingForASpot]

Yes I am very confused by this... It was never mentioned what part of the cycle this is.

So it is true that the thecal cells secrete these hormones during the follicular phase and then afterwards the corpus luteum secretes it?

 

[Mantis Toboggin]

Is the answer B? Afaik progesterone and HcG are only responsible for MAINTAINING the uterine lining, not for growing it. That is the job of estrogen and the follicular cells that make it

 

[Mantis Toboggin]

This question seems incorrect tbh. Neither A nor D should be considered answer choices because they include progesterone. Progesterone, according to Kaplan and EK, is only responsible for maintaining the lining, not for growing it. Growing it is due to estrogen, not progesterone.


The correct answer according to Berkeley is A btw, since OP didn't bother mentioning it