Question

Mention the source and the functions of the above mentioned hormones.

Hint:

Remember that hCG, Relaxin, and human Placental Lactogen (hPL) are unique endocrine markers synthesized exclusively in women during pregnancy.

Answer 1

Concept: Each reproductive hormone targets specific tissues to regulate follicular growth, support the early embryo, or structurally alter maternal anatomy during pregnancy. Comprehensive Hormonal Profiles:
• FSH (Follicle Stimulating Hormone):
• Anatomical Source: Secreted by the gonadotroph cells of the anterior pituitary gland.
• Biological Functions: It stimulates the proliferation of ovarian granulosa cells, promoting the growth and maturation of primary follicles into mature Graafian follicles. It also upregulates LH receptor expression on these developing cells.
• LH (Luteinizing Hormone):
• Anatomical Source: Secreted by the gonadotroph cells of the anterior pituitary gland.
• Biological Functions: A major surge in LH levels induces the rupture of the mature Graafian follicle, releasing the secondary oocyte into the fallopian tube (ovulation). Following ovulation, LH transforms the remnants of the ruptured follicle into a temporary endocrine gland called the corpus luteum.
• hCG (Human Chorionic Gonadotropin):
• Anatomical Source: Secreted by the trophoblast cells of the developing blastocyst, which later forms the chorionic villi of the maternal-fetal placenta.
• Biological Functions: It prevents the degeneration of the corpus luteum at the end of a non-fertilised cycle. By sustaining the corpus luteum, it ensures the continuous secretion of high levels of progesterone, which is absolutely vital for maintaining the vascular integrity of the uterine endometrium during early pregnancy.
• Relaxin:
• Anatomical Source: Secreted primarily by the corpus luteum of the ovary during pregnancy, and later in smaller amounts by the maternal placenta and decidua.
• Biological Functions: Relaxin targets the connective tissues of the pelvis. It relaxes the interpubic fibrocartilage of the pubic symphysis and increases the flexibility of pelvic ligaments. It also helps dilate and soften the cervix during labor, facilitating the smooth passage of the fetus through the birth canal.