Question

The main function of mammalian corpus luteum is to produce
A) Estrogen daily
B) Progesterone
C) Human chorionic gonadotropin
D) Relaxin only

Answer 1

Hint: Progesterone is secreted by corpus luteum after ovulation .In case fertilization doesn’t occur corpus luteum degenerates into corpus albicans.

Complete answer:
Menstrual cycle is a monthly cycle in females which starts at puberty. It is divided into the following phases:
a. Menstrual phase: In this phase blood and menses shed from the uterus which was prepared for implantation. It occurs when fertilization doesn’t occur and lasts for 3-5 days. Endometrium lining is sloughed off.
b. Follicular phase: Follicular development occurs in this phase. The primary follicle becomes the Graafian follicle. FSH is released from the ovary. The proliferation of endometrium occurs. It lasts for 5 th -13 th days. Estrogen is secreted from the ovary.
c. Ovulatory phase: Ovulation occurs on 14 th day. LH is secreted by the pituitary and the ovum is released from the Graafian follicle as it ruptures. An increase in LH is called the LH surge. Ovum reaches
ampullary –isthmus junction and waits for sperm.If fertilization doesn’t occur ovum degenerates and the next phase starts.
d. Luteal phase: Lasts for 15-28 th day and is also known as the secretory phase. Graafian follicle after ovulation becomes corpus luteum and secretes progesterone. Progesterone maintains pregnancy and is known as the pregnancy hormone. When fertilization occurs corpus luteum continues producing progesterone and if fertilization doesn’t occur corpus luteum degenerates and forms corpus albicans after which endometrium starts to slough off and the menstrual phase starts.
Hence option B is correct corpus luteum produces progesterone.

Note: In luteal or secretory phase Graafian follicle becomes corpus luteum and releases
progesterone which maintains pregnancy and prepares the uterus for implantation in case fertilization
happens