Q.Name the functions of the following:

The corpus luteum is the yellowish structure formed from the ruptured Graafian follicle after ovulation. It secretes progesterone, which is essential for maintaining the endometrium during pregnancy. If fertilization does not occur, the corpus luteum degenerates, causing progesterone levels to fall and menstruation to begin.

The endometrium is the inner glandular lining of the uterus that undergoes cyclic changes during the menstrual cycle. It thickens and becomes richly vascularized to prepare for implantation of the embryo. If fertilization occurs, the blastocyst embeds itself in this layer; if not, the endometrium breaks down and is shed during menstruation.

The acrosome is a cap-like structure covering the anterior part of the sperm head. It contains enzymes (hyaluronidase and others) that help the sperm penetrate the layers surrounding the ovum during fertilization.

The sperm tail, or flagellum, provides motility to the sperm. Its whip-like movements propel the sperm through the female reproductive tract toward the ovum. …

The reproductive system is a marvel of coordinated structures, each performing tasks essential to the creation and nurturing of new life. Understanding what each part does reveals how conception, implantation, and early pregnancy unfold.

(a) Corpus Luteum

After ovulation, the ruptured Graafian follicle transforms into the corpus luteum, a temporary endocrine gland in the ovary. Its primary function is hormonal: it secretes large amounts of progesterone, which is essential for maintaining the endometrium in a thickened, secretory state suitable for implantation. If fertilization occurs, the corpus luteum continues to produce progesterone (and some estrogen) during early pregnancy, preventing menstruation and supporting the developing embryo until the placenta takes over hormone production. If fertilization does not occur, the corpus luteum degenerates into the corpus albicans, progesterone levels drop, and menstruation begins.

(b) Endometrium

The endometrium is the inner glandular lining of the uterus, and it undergoes cyclical changes throughout the menstrual cycle. Its main function is to provide the site for implantation of the blastocyst and to nourish the embryo in the early stages of pregnancy. Under the influence of estrogen and progesterone, the endometrium thickens and becomes richly vascularized, creating an optimal environment for the fertilized egg to embed itself. If implantation does not occur, the endometrial lining breaks down and is shed during menstruation. Once pregnancy is established, the endometrium (now called the decidua) contributes to the formation of the placenta.

(c) Acrosome

The acrosome is a cap-like structure that covers the anterior portion of the sperm head. It is essentially a specialized lysosome filled with hydrolytic enzymes, including hyaluronidase and acrosin. The function of the acrosome is to facilitate fertilization: when a sperm reaches the ovum, the acrosome undergoes the acrosomal reaction, releasing these enzymes. The enzymes digest the protective layers surrounding the egg—the corona radiata and the zona pellucida—allowing the sperm to penetrate and fuse with the egg membrane. Without a functional acrosome, sperm cannot breach these barriers, and fertilization fails.

(d) Sperm Tail …