Packet 13

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Packet 13

• Human Reproduction and Development

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Aim How does the structure of the human
reproduction system relate to its functions?

• (A) SEXUAL REPRODUCTION
• Reproduction is the production of a new offspring
• Two typessexual and asexual
• Sexual reproduction always involves
• Fertilization fusion of nuclei of egg and sperm
  to form a zygote
• Development growth of the zygote into a new
  individual

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Fertilization can be either internal or external

• Internalfertilization occurs inside the female
  bodyfewer eggs because there is a better chance
  of survival

• Externalfertilization occurs outside the body in
  the environmentcommon in aquatic plants and
  animalseggs and sperm are released directly into
  the waterrisky so there are large numbers of
  eggs and sperm released

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(B) SEXUAL DEVELOPMENT

• Reproductive system is the only system in the
  human body in which the organism can still lead a
  healthy life if it is not used or working
  properly
• First 6 weeks of developmentmales and females
  are identical
• 7th week in which the primary reproductive organs
  develop

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Gonadsreproductive organs

• Malestestesproduce testosterone
• Femalesovariesproduce estrogen
• Production of the hormones determine whether the
  embryo will develop physically into a male or
  female

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(C) MALE REPRODUCTIVE SYSTEM

• main function is to produce and deliver sperm

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STRUCTURE

• Testesprimary male reproductive organproduces
  testosterone
• Scrotumsac that contains the testes
• Seminiferous tubules tiny tubules where sperm
  is produced
• Epididymis where sperm matures and is stored

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• Vas deferens extends into the abdominal cavity
  where it meets with the urethra
• Urethra tube that leads outside the body
  through the penis
• Seminal vesicle, prostate gland and bulbourethral
  glandproduce seminal fluidsemen2.5 million
  sperm per drop

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SPERM STRUCTURE

• Headcontains the nucleus-contains _______
• Midpiececontains mitochondria for __________
• Tailused to propel the sperm towards the egg