Which of the following is a mass within the ovary that secretes hormones to maintain the uterine lining during pregnancy?
A.
Oviduct
B.
Corpus luteum
C.
Oocyte
D.
Umbilical cord
The Correct Answer and Explanation is:
The correct answer is B. Corpus luteum.
Explanation:
The corpus luteum is a temporary endocrine structure in the ovary that plays a crucial role in maintaining pregnancy. After ovulation, when the mature egg is released from the ovary, the ruptured follicle transforms into the corpus luteum. This structure is named for its yellow color (“corpus luteum” means “yellow body” in Latin).
The primary function of the corpus luteum is to secrete hormones that support the early stages of pregnancy. It produces significant amounts of progesterone and some estrogen. These hormones are vital for maintaining the uterine lining (endometrium), which is necessary for the implantation and sustenance of a fertilized egg. Progesterone, in particular, prepares the endometrium to be receptive to the embryo and helps to keep the uterine lining thick and nutrient-rich throughout the initial stages of pregnancy.
If pregnancy does not occur, the corpus luteum degenerates after about 14 days, leading to a decrease in progesterone levels. This hormonal drop triggers the shedding of the uterine lining, resulting in menstruation. If pregnancy does occur, the corpus luteum continues to produce progesterone until the placenta is sufficiently developed to take over this hormone production around the end of the first trimester.
Here’s a brief look at why the other options are not correct:
- A. Oviduct: Also known as the fallopian tube, this is where fertilization typically occurs, but it does not secrete hormones related to maintaining the uterine lining.
- C. Oocyte: This is the egg cell within the ovary that is released during ovulation. It does not produce hormones but is involved in fertilization.
- D. Umbilical cord: This structure connects the fetus to the placenta and provides nutrients and oxygen but does not secrete hormones related to maintaining the uterine lining.
The corpus luteum is therefore the key structure responsible for secreting hormones essential for sustaining the uterine lining during early pregnancy.