Question

What is the significance of ampullary-isthmic junction in the female reproductive tract?

Answer 1

The fallopian tube consists of four parts. They are, approaching the uterus from near the ovary inward, the infundibulum and its associated fimbriae near the ovary, the ampulla that represents most of the lateral tubes, the isthmus, which is the narrower part of the tube that links to the uterus, and the interstitial or intramural part, the narrowest part of the uterine tube, which crosses the muscles of the uterine.

Complete answer:
The fertilization process occurs at the junction of the isthmus of the female reproductive tract and the ampulla of the fallopian tube (ampullary-isthmic junction). Fertilization occurs only when the egg and sperm are transported to the junction of the ampulla at the same time. All mating will not lead to fertilization or pregnancy.
The ampulla is about half the length of the oviduct. The mucosa is complex and well developed, while the muscle is thin. It is soft to touch and the diameter is larger than isthmus. The region of the ampulla changes to the span region at the junction of the ampulla.
Ampullary-isthmic junction is located roughly halfway between the ovary and the uterus. This is roughly where fertilization takes place. Isthmus is the part between the ampulla and the uterotubal junction is the isthmus and is half the length of the oviduct. The muscularis is well developed, giving the isthmus a solid feel.

Note:
The reproductive tract (or genital tract) is the lumen that begins with a single passage through the vagina, divides into two lumens in the uterus, both extending through the fallopian tubes and ending at the distal ostia which opens into the abdominal cavity. In the absence of fertilization, the ovum eventually travels through the entire reproductive system from the fallopian tubes to the exit of the vagina by menstruation.