Female Reproductive System: A Comprehensive Guide

Female Reproductive System

Key Components and Functions

Uterus

The myometrium, the middle layer of the uterine wall, is responsible for the contractions during childbirth.

Vagina

The vagina is an elastic tube that facilitates penetration during sexual intercourse.

Vulva

The vulva, the external female genitalia, consists of the labia majora, labia minora, and the clitoris, which is responsible for sexual pleasure.

Bartholin's Glands

These glands produce lubricant to facilitate sexual intercourse.

The Ovarian Cycle

Each ovarian cycle lasts approximately 28 days and consists of three phases:

1. Follicular Phase (14 days): An egg cell matures.
2. Ovulation: The mature egg is released from the ovary into the fallopian tube.
3. Luteal Phase (14 days): The corpus luteum, a mass of cells remaining in the ovary, produces hormones to maintain the endometrium.

The Uterine Cycle

The uterine cycle begins with the menstrual phase (3-5 days), followed by the rebuilding of the uterine lining. Progesterone, produced by the corpus luteum, maintains the lining. If fertilization does not occur, the lining sheds, initiating a new cycle.

Fertilization and Pregnancy

Fertilization occurs in the fallopian tubes. Millions of sperm are released during ejaculation, but only one fertilizes the egg, forming a zygote. The zygote undergoes mitosis, developing into a morula and then a blastula. Upon reaching the uterus, the blastula implants, marking the beginning of pregnancy.

Embryonic Stage

The embryo develops within the amnion, a membrane filled with amniotic fluid. The placenta forms, providing nutrients and waste removal.

Fetal Stage

From the third month until birth, the embryo is considered a fetus. It develops a human shape and its organs continue to grow.

Birth

Pregnancy typically lasts 40 weeks. Birth begins with cervical dilation and often the rupture of the amniotic sac (water breaking). A cesarean section may be performed if complications arise. The placenta is expelled shortly after birth.

Fraternal Twins

Fraternal twins occur when two eggs are released during ovulation and fertilized by two different sperm.