How is the oocyte transported from ovary to uterus?

The oocyte, also known as the egg cell, is transported from the ovary to the uterus through a series of coordinated events involving muscular contractions and ciliary action. This process is known as oviductal transport or ovum transport.

Here's an overview of how the oocyte is transported:

1. Ovulation: During ovulation, a mature oocyte is released from the ovary. The release of the oocyte is triggered by a surge in luteinizing hormone (LH).

2. Fimbriated Funnel: The fimbriae, which are finger-like projections at the end of the fallopian tube, capture the released oocyte.

3. Ciliary Action: The fallopian tubes are lined with ciliated cells. The cilia beat in a wave-like motion, creating a fluid current that helps move the oocyte toward the uterus.

4. Peristaltic Contractions: The smooth muscle cells of the fallopian tubes undergo rhythmic contractions known as peristaltic waves. These contractions help propel the oocyte along the fallopian tube.

5. Fertilization: If sperm are present in the fallopian tube, fertilization can occur. Fertilization typically takes place in the outer third of the fallopian tube, known as the ampulla.

6. Continuation of Transport: After fertilization, the now-fertilized egg, called a zygote, continues to be transported through the fallopian tube toward the uterus. The journey takes approximately 3-4 days.

7. Entry into the Uterus: The zygote reaches the uterus and enters the uterine cavity through the uterotubal junction, which is the junction between the fallopian tube and the uterus.

8. Implantation: The zygote undergoes further cell divisions and transforms into a blastocyst. The blastocyst then hatches out of its protective outer layer and implants into the uterine lining (endometrium), where it continues to develop into an embryo and eventually a fetus.

It's important to note that successful oocyte transport is crucial for fertilization and the establishment of pregnancy. Factors that can disrupt oviductal transport, such as scarring or blockages in the fallopian tubes, can affect fertility and the ability to conceive.