What occurs during the secretory phase of the uterine cycle?

• A. Ovulation occurs, releasing an egg from the ovary.
• B. The endometrium sheds, leading to menstruation.
• C. The follicular phase begins, stimulating follicle development.
• D. The endometrium thickens and secretes nutrients to prepare for potential implantation.

Answer: (D)

Verified step by step guidance

1. Understand the uterine cycle: The uterine cycle is divided into three phases: the menstrual phase, the proliferative phase, and the secretory phase.
2. Identify the secretory phase: This phase occurs after ovulation and is primarily influenced by the hormone progesterone, which is secreted by the corpus luteum.
3. Recognize the role of progesterone: Progesterone causes the endometrium (the lining of the uterus) to thicken and become more glandular, preparing it to support a potential pregnancy.
4. Note the changes in the endometrium: During the secretory phase, the endometrial glands enlarge and secrete nutrients, creating a supportive environment for a fertilized egg to implant.
5. Connect to the overall cycle: If implantation does not occur, the corpus luteum degenerates, leading to a decrease in progesterone and the onset of menstruation, marking the end of the secretory phase.