Human Sexual Development and Female Reproductive Anatomy
Stages of Sexual Maturity and Development
The journey from birth until early adulthood involves several distinct stages:
- Children: Primary sexual characteristics. At birth, a baby already has formed reproductive systems: the penis and scrotum in boys, and the vulva in girls. Childhood is a stage that extends from birth to approximately ten years of age.
- Puberty: Secondary sexual characteristics. Between ten and fourteen years of age, the maturation of organs occurs. In girls, menarche occurs, and in boys, the production of sperm begins. At maturity, the reproductive organs begin to produce hormones that cause the appearance of secondary sexual characteristics, thereby increasing the physical differences between girls and boys.
- In girls, breasts grow, hips widen, and pubic and armpit hair appear.
- In boys, the thickness of bone and muscle mass increases, the voice becomes deeper, and the beard, pubic hair, and armpit hair appear.
- Adolescents: Sexual maturity. This stage involves developing secondary sexual characteristics, a process that lasts between two and five years. This stage is known as adolescence and, upon reaching it, the body is ready for reproduction.
- Adulthood: The end of development. Following the late teens, an individual reaches adulthood, typically around the early twenties.
The Female Reproductive System and Anatomy
- Ovaries: These have the shape and size of an almond. They are attached to the uterus by a ligament. In these organs, eggs mature.
- Fallopian tubes: These connect each ovary to the uterus. The interior is lined with cilia that push the egg forward.
- Uterus: A hollow organ with the inside coated with a highly vascular epithelium known as the endometrium, where the fertilized egg is implanted. It has a narrowing called the cervix, which connects to the vagina.
- Vagina: A muscular wall through which the uterus connects to the outside. Its lower end opens to the exterior through a vaginal opening.
- Clitoris: A body with many nerve endings, giving it great sensitivity. It is located at the junction of the labia minora.
- Labia Majora: Folds of skin located between the thighs, covering the rest of the external genitalia.
- Labia Minora: Thin and sensitive folds of skin which are covered by the labia majora.
Female Gametes: The Egg
The egg is the female gamete. It is a very large cell, about 1mm in diameter, that matures within the ovary inside a capsule called a follicle de Graaf.
The Graafian follicle forms during the days of the menstrual cycle. During the first two weeks, one egg matures. During the next two weeks, it produces progesterone.