Read the passage and answer the following questions:
The major events of the cycle starts with the menstrual phase, when menstrual flow occurs and it lasts for 3-5 days. The menstrual flow results due to breakdown of endometrial lining of the uterus and its blood vessels which forms liquid that comes out through vagina. Menstruation only occurs if the released ovum is not fertilised. Lack of menstruation may be indicative of pregnancy. However, it may also be caused due to some other underlying causes like stress, poor health etc. The menstrual phase is followed by the follicular phase. During this phase, the primary follicles in the ovary grow to become a fully mature Graafian follicle and simultaneously the endometrium of uterus regenerates through proliferation. These changes in the ovary and the uterus are induced by changes in the levels of pituitary and ovarian hormones.

Which among the following secretes large amounts of progesterone?

Corpus luteum.

The correct answer is Option (2)-Corpus luteum.

Among the options provided, the structure that secretes large amounts of progesterone is the "Corpus Luteum."

The corpus luteum is a temporary endocrine structure that forms in the ovary from the remnants of the ovarian follicle after ovulation. Its primary function is to produce progesterone, a hormone crucial for preparing and maintaining the uterine lining for potential implantation of a fertilized egg (embryo). If fertilization occurs, the corpus luteum continues to produce progesterone to support early pregnancy until the placenta takes over this function. If fertilization does not occur, the corpus luteum regresses, leading to a decrease in progesterone production and triggering the start of a new menstrual cycle.

The zona pellucida is a layer surrounding the egg (oocyte) and plays a role in the fertilization process.

The corona radiata refers to the layer of cells surrounding the zona pellucida of an oocyte released from the ovary during ovulation.

The antrum is a fluid-filled cavity within the ovarian follicle that contains follicular fluid. It does not secrete progesterone; rather, it provides a conducive environment for the development of the oocyte within the follicle.