MCAT Question A Day - 7/10/14 - Answer!
The inner linings of the Fallopian tubes are covered with a layer of cilia. The purpose of this layer is to:
A. remove particulate matter that becomes trapped in the mucus layer covering the Fallopian tubes.
B. maintain a layer of warm air close to the inner lining, protecting the ovum from temperature changes occurring in the external environment.
C. kill incoming sperm, thus preventing fertilization
D. facilitate movement of the ovum towards the uterus.
D is correct. The layer of cilia along the inner lining of the Fallopian tubes serves to help the egg cell move towards the uterus, where it will implant if it has been fertilized. (Fertilization usually happens in the Fallopian tubes.) A describes what the ciliary lining in the respiratory tract does. B may sound good, but the Fallopian tubes are far enough away from the extemal environment that protection from its temperature fluctuations is not an issue. C would seem to gum up the whole "continuation of the species" plan. It's not a good answer.
D is correct. The layer of cilia along the inner lining of the Fallopian tubes serves to help the egg cell move towards the uterus, where it will implant if it has been fertilized. (Fertilization usually happens in the Fallopian tubes.) A describes what the ciliary lining in the respiratory tract does. B may sound good, but the Fallopian tubes are far enough away from the extemal environment that protection from its temperature fluctuations is not an issue. C would seem to gum up the whole "continuation of the species" plan. It's not a good answer.
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