Gametogenesis: Oogenesis Process

Human Life Cycle

• The human life cycle begins with fertilization and is accompanied by a series of growth and developmental events that allow the full formation of the offspring.
• The chromosome number is restored in the zygote after fertilization.

Human Life Stages

• Infancy: 0 to 2 years old, with continuous physical development.
• Childhood: 1 to 12 years old, with locomotor and cognitive skills development.
• Adolescence: 13 to 19 years old, with various changes related to puberty.
• Adulthood: 20 years and onwards, with sexual maturity physically and behaviorally.

Human Reproduction

• Human reproduction is exclusively sexual, with genetic material from two sources.
• No viable asexual means, preventing mutations from increasing.

Male Reproductive Anatomy

• Testis: male gonad that produces and nourishes sperm cells.
• Scrotum: external sac that regulates temperature for testis.
• Epididymis: stores sperm cells produced and transports them to vas deferens.
• Urethra: common exit duct for both urine and semen.
• Vas deferens: pathway of sperms from testis to the urethra.
• Seminal vesicle: contributes alkaline fluid that nourishes and protects sperm cells.
• Prostate gland: contributes a fluid that neutralizes semen and vaginal fluid.
• Bulbourethral gland: contributes a fluid that functions for lubrication.
• Penis: copulatory organ that conveys sperm to female reproductive tract.

Female Reproductive Anatomy

• Ovary: female gonad that produces and nourishes egg cells.
• Fallopian tubes: ducts that serve as fertilization site and lead to the uterus.
• Fimbriae: appendages of the fallopian tubes that catch eggs during ovulation.
• Uterus: highly vascularized sac that nourishes the developing embryo.
• Cervix: narrow channel that prevents further entry of foreign materials.
• Vagina: receives sperm cells and serves as the birth canal.
• External genitalia: accessory structures of the female reproductive system.
• Bartholin's gland: produces fluid that serves as lubrication during intercourse.

Gametogenesis

• Spermatogenesis: occurs in the seminiferous tubules of the male testis, involving proliferation, growth, maturation, and differentiation.
• Oogenesis: occurs in the ovaries and fallopian tubes, involving proliferation, growth, maturation, and differentiation.

Gametogenesis: Spermatogenesis

• Proliferation: spermatogonium undergoes several mitotic divisions to produce more spermatogonia.
• Growth: spermatogonia undergo minimal growth and further division to become primary spermatocytes.
• Maturation: involves the meiotic division of the primary spermatocyte.
• Differentiation: each spermatid differentiates to become a functional and motile spermatozoon.

Gametogenesis: Oogenesis

• Proliferation: each oogonium undergoes mitotic division to produce more oogonia.
• Growth: each oogonium then undergoes significant growth to become primary oocytes.
• Maturation: involves the meiotic division of the primary oocyte to reduce chromosome number.
• Differentiation: the ootid is a very transient stage, eventually becoming the ovum with minimal differentiation.

Embryonic and Fetal Development

• Organogenesis occurs during embryonic development.
• Organogenesis occurs during fetal development.
• The pre-implantation embryonic development stage occurs after fertilization, where the fertilized egg travels into the uterus and is implanted.

Learn about the process of oogenesis during gametogenesis, including stages like proliferation, growth, maturation, and differentiation. Understand how oogonia develop into primary oocytes through mitotic division and meiotic division.