Question

Study the flow chart given below. Name the hormones involved at each stage and explain their functions.

Hypothalamus

$\downarrow$

Pituitary

$\downarrow$

ovary

$\downarrow$

Pregnancy

Answer 1

Hypothalamus - Gonadotropin-Releasing Hormone. This acts on the pituitary hormone gland to release Gonadotropins like LH and FSH. Pituitary Gland - Follicle stimulating hormone (FSH) and Luteinising Hormone (LH). FSH stimulates development of follicles. The LH stimulates ovulation and maintenance of corpus luteum. Ovary - The follicles then secrete estrogen which stimulates growth of endometrium and uterus. It also helps in the development of secondary sexual characters. The tertiary follicles change into corpus luteum which secretes progesterone. It helps in the development of endometrium and facilitates implantation. Pregnancy: Estrogen released by placenta. It helps in the growth of the uterus to accommodate the growing foetus. Human Chorionic Gonadotropin (HCG) gives signals to the corpus luteum to continue to release progesterone to maintain endometrium. Human Placental Lactogen (hPL) promotes growth of mammary glands. Relaxin helps in lengthening and softening of cervical muscle and is also responsible for the expansion of lower pelvic region of mother helping the baby to come out easily.