Understanding Human Development

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Understanding Human Development
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Reproductive Systems

• We know that male and female gonads produce
  gametes.
• What makes the gonads start producing gametes?
• HORMONES!
• A substance that acts like messengers in the body
• Travel through the bloodstream
• Cause cells to respond in certain ways
• Several hormones regulate the reproductive system

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Reproductive Systems

• Reproductive hormones start to kick in during the
  early to mid teens.
• Puberty is the time when hormone signals change
  the body so it is able to reproduce.
• Pituitary gland starts to produce FSH.
• FSH travels to the gonads and signals them to
  start producing gametes.
• Other hormones start the secondary sexual
  characteristics.

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Puberty in Males

• FSH stimuleates the development of
  sperm-producing tubes in the testes and the
  development of sperm.
• Sperm is then produced DAILY for the rest of
  their lives.
• Cells in the testes produce the hormone
  Testosterone - influences secondary sexual
  characteristics.

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Puberty in Females

• FSH stimulates the ovaries to begin maturing and
  releasing eggs.
• One egg is released each month.
• FSH also stimulates the production of estrogen
  which influences secondary sexual characteristics.

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Male Reproductive Anatomy

• Designed to produce as many healthy sperm as
  possible.
• Sperm are produced in the testes - outside the
  main body where it is cooler.
• Sperm are produced in the seminiferous tubules.
• 350 - 500 million sperm are produced each day.
• Sperm are stored in long coiled tubes in the
  testes called the epididymis.

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Male Reproductive Anatomy

• Sperm travel through the vas deferens.
• To help sperm move (swim) they are in a nutrient
  rich fluid supplied by the prostate glad and the
  seminal vesicles.
• These glands release this fluid into the vas
  deferens where it mixes with the spem - now
  called semen.

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Male Reproductive Anatomy
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Seminiferous Tubule
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Seminiferous Tubule