HUMAN BIO LONG Q

• Reproduction is an important biological feature among living organisms that enable them to persist for many generations
• The process of reproduction in humans must be followed by various developmental processes during gestation that lead to the formation of a fully functional individual

  
• Human Life Cycle


  1. Zygote develops into embryo, then grows into adult

  2. Chromosome number restored in zygote after fertilization

  3. Gametes deliver and combine parents' DNA

  4. Fertilization and meiosis alternate during life cycle
• Human Life Stages


  • Infancy (0-2 years)
  • Childhood (1-12 years)
  • Adolescence (13-19 years)
  • Adulthood (20+ years)
• Childhood

  • Locomotor and cognitive skills development
• Adolescence


  • Undergoing various changes related to puberty
• Adulthood


  • Sexually mature physically and behaviorally
• Various changes during puberty in humans serve as physical, physiological, and behavioral preparations for adulthood
• Human Reproduction


  • Mode is exclusively sexual
  • No viable asexual means
  • Genetic material from two sources
  • Prevents mutations from increasing
• Male Reproductive Anatomy


  • Testis
  • Scrotum
  • Epididymis
  • Urethra
  • Vas deferens
  • Seminal Vesicle
  • Prostate Gland
  • Bulbourethral Gland
  • Penis

  
• 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 the 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
  • Fallopian Tubes
  • Fimbriae
  • Uterus
  • Cervix
  • Vagina
  • External Genitalia (vulva)
  • Bartholin's Gland

  
• Ovary


  Female gonad that produces and nourishes egg cells
• Fallopian Tubes


  Ducts that serve as fertilization site and leads 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 the sperm cells and serves as the birth canal
• External Genitalia (vulva)


  Accessory structures of the female reproductive system
• Bartholin's Gland


  Produces fluid that serves as lubrication during intercourse
• Gametogenesis


  1. Reduction of the chromosome number

  2. Spermatogenesis or oogenesis

  3. Makes sperm cells sufficiently motile

  4. Produces egg cells with enough nutrients
• Spermatogenesis


  1. Proliferation

  2. Growth

  3. Maturation

  4. Differentiation

  
• Spermatogenesis occurs in the seminiferous tubules of male testis

  
• Spermatogenesis starts during puberty and continuous throughout life

  
• Oogenesis


  1. Proliferation

  2. Growth

  3. Maturation

  4. Differentiation
• Oogenesis occurs in the ovaries and fallopian tubes
• Oogenesis starts during the pregnancy of the mother
• Human fertilization involves the fusion of gametes from male and female parents
• Fertilization produces the zygote with normal or restored chromosome number
• Pre-Implantation Phase


  1. Zygote undergoes repeated cell divisions and reorganization

  2. Dividing ball of cells travel down into the uterus through the fallopian tube

  3. Implantation occurs during the blastocyst stage
• Implantation and Gastrulation


  Offspring becomes a three-layered embryo through gastrulation
• Extraembryonic Membranes


  • Amnion
  • Yolk sac
  • Allantois
  • Chorion