hormones in human reproduction

• hormones are produced in:

  • pituitary gland
  • pancreas
  • adrenal glands
• hormones are transported to target organs through the blood stream
• the two main types of hormones are proteins or steroids
• at puberty, the body starts releasing sex hormones that trigger off secondary sexual characteristics and cause eggs to mature in women
• in men, the main reproductive hormone is testosterone which is produced by the testes and stimulates sperm production
• in women, the main reproductive hormone is oestrogen which is produced by the ovaries and is involved in physical changes and the menstrual cycle
• male changes occurring in puberty:

  • growth spurts
  • body hair
  • mood swings
  • deeper voice
  • broader shoulders
  • growth of penis
  • facial hair
• female changes occurring in puberty:

  • hip growth
  • menstrual cycle
  • breast growth
  • deeper voice
  • body hair
  • general growth
  • mood swings
• both gender changes during puberty:

  • general growth
  • body hair
  • mood swings
• uterus - in a pregnant woman the baby would grow here
• fallopian tube - carries the egg to the uterus every month
• ovaries - where the eggs are made
• vagina - receives the sperm
• cervix - the opening to the uterus
• seminal vesicles - adds fluids to the sperm to make semen
• sperm tube - carries sperm to the penis
• testes - where sperm are made
• penis - carries the sperm out of the body
• scrotum - a bag of skin that holds the testes
• girls have all their eggs at birth, but men make sperm throughout their life
• menopause is when the supply of eggs runs out and the womans periods stop
• the menstrual cycle is a cycle of changes in hormone production and uterus structure
• the menstrual cycle is to best prepare the body for a potential pregnancy
• FSH is made in the pituitary gland and causes the eggs in the ovary to mature in a structure called a follicle and stimulates the ovaries to produce and release oestrogen
• oestrogen is produced in the ovaries and stimulates the womb lining to build up and stimulates the release of LH and inhibits the release of FSH
• LH is produced in the pituitary gland and stimulates the release of the egg at ovulation (day 14)
• progesterone is made in the ovaries by the empty egg follicle and stimulates the womb lining to build up and maintain and inhibits the release of LH and FSH
• stage one of the menstrual cycle:

  the uterus lining breaks down for about 4 days
• stage two of the menstrual cycle:

  the uterus lining builds up again, from day 4-14, into a thick spongy layer full of blood vessels, ready to receive a fertilised egg
• stage three of the menstrual cycle:

  an egg develops and is released from the ovary at day 14 - this is called ovulation
• stage four of the menstrual cycle:

  the wall is then maintained for about 14 days until day 28, if no fertilised egg has landed on the uterus wall by day 28, the spongy lining starts to break down and the whole cycle starts again
• order of events in the menstrual cycle:

  1. pituitary gland releases FSH
  2. FSH triggers ovary to mature egg and release oestrogen
  3. oestrogen tells lining to build up and stops the release of FSH and stimulates the release of LH
  4. LH stimulates the release of the egg
  5. empty egg follicle releases progesterone
  6. progesterone stimulates the womb lining to build up and remain and tells the pituitary gland to inhibit the release of FSH and LH