Puberty: Changes in Adolescents

• Reproduction is essential for the continuation of species and begins during puberty.
• Puberty occurs between ages 11-13 in girls and 12-14 in boys
• Puberty marks sexual maturity and is characterized by various changes in adolescents
• At birth, primary sexual characteristics differentiate girls and boys
• Puberty is a period of morphological changes in adolescents, indicated by genital organs becoming active
• Modifications during puberty are considered secondary sexual characteristics

Manifestations of Puberty in Boys

• Appearance of hair on the pubis, armpits, body, and face
• Development of the genital system
• Production of sperm
• Increased height, widening of shoulders, and muscle development
• Deepening of the voice and formation of the Adam's apple
• Occurrence of acne and changes in behavior

Manifestations of Puberty in Girls

• Beginning of menstruation
• Development of the breasts and vulva
• Appearance of hair on the pubis and armpits
• Widening of the pelvis
• Occurrence of acne and changes in behavior

Roles of Genitals in Men

• The male genital system includes the penis and testicles
• Testicles are enclosed by bursae or scrotums
• The epididymis extends from the testicles to the spermiducts or vas deferens
• Seminal vesicles and the prostate open into the urethra or urogenital conduit

Experiments on Male Genital Tract

• Destruction of testicles in a young boy results in sterility and absence of secondary sexual characteristics.
• Cutting or ligating the spermiducts of a boy causes sterility but doesn't affect secondary sexual characteristics.
• Regular injection of products from the testicles into a castrated young person maintains sterility, but secondary sexual characteristics appear.
• Testicles produce sperm and substances responsible for the appearance of secondary sexual characteristics (gonads)
• Sperm produced in the testicles pass through the spermiducts or vas deferens
• The appearance of secondary sexual characteristics is due to a substance released by the testes into the blood

Roles of Genitals in Women

• The female genital tract includes the vulva, vagina, uterus, oviducts or fallopian tubes, and ovaries
• The opening of the vagina is hidden by a thin membrane called the hymen

Experiments on Female Genital Tract

• Oophorectomy leads to sterility, cessation of periods, and disappearance of secondary sexual characteristics
• Sectioning or ligation of the oviducts causes sterility, but menstruation and secondary sexual characteristics persist
• Transplantation of an ovary in a castrated subject restores menstruation and secondary sexual characteristics, but sterility remains

Ovaries

• Ovaries produce female gametes (eggs) and secrete female hormones (estrogens and progesterone).
• Substances secreted by the ovary are responsible for menstruation, secondary sexual characteristics, and the production of female gametes
• Gametes produced by the ovary pass through the oviducts or fallopian tubes
• A single ovary can ensure the functioning of the body

Comparison of Genitals

• Male gonads: Testicles
• Female gonads: Ovaries
• Male genital tract: Epididymis, Vas deferens, Urogenital conduit
• Female genital tract: Fallopian tubes, Uterus, Vagina
• Male copulatory organ: Penis
• Female copulatory organ: Vagina
• Male accessory glands: Prostate, Seminal vesicles
• Female accessory gland: Cervix
• Female gestational organ: Uterus

The Menstrual Cycle

• The menstrual cycle lasts about 28 days and begins at puberty and continues until menopause (ages 45-50) unless interrupted by pregnancy
• The ovarian cycle and uterine cycle are distinguished within the menstrual cycle

The Ovarian Cycle

• Ovaries contain spherical structures called follicles, which contain gametes
• Follicles reach maximum development and expel the egg (ovulation) around the middle of the cycle
• The ovarian cycle includes the pre-ovulatory phase and post-ovulatory phase

Pre-ovulatory Phase

• The duration of this phase varies and involves the development of follicles from the first day of the cycle
• Growing follicles secrete estrogen, with only one maturing into a mature follicle, which releases the egg on the 14th day (ovulation)

Post-ovulatory Phase

• Fixed duration of 14 days
• After ovulation, the remaining follicle transforms into the corpus luteum, which secretes estrogen and progesterone

The Uterine Cycle

• Uterine cycle occurs simultaneously with the ovarian cycle
• Uterine cycle marked by the appearance of menstruation
• The lining of the uterus (endometrium) develops and thickens after menstruation, creating a highly vascularized "uterine lace"
• The uterus becomes ready to receive an embryo in anticipation of fertilization
• If fertilization does not occur, the uterine mucosa is destroyed, causing hemorrhage, which results in menstruation for 3 to 5 days
• The uterus returns to its initial size after menstruation
• During the pre-ovulatory phase, the thermal curve oscillates below 37°, while in the post-ovulatory phase, it slightly exceeds 37°

Conclusion

• Sexual development and functioning begin at puberty in both sexes, initiated by the genitals producing hormones and gametes
• Gametes produced can meet, which is fertilization