The Endocrine system

• parts of the endocrine system

  thyroid, parathyroid, adrenal glands, testes, pituitary gland, thymus, pancreas, ovaries
• what are hormones

  hormones are chemical messengers produced by glands specific to particular target cells
• what are hormones made from

  proteins
• where are hormones produced

  glands that make up the endocrine system
• how are hormones transported

  in the bloodstream
• where do hormones effect

  specific target cells that have the correct receptors to respond to that hormone
• adrenaline

  a hormone released by your adrenal glands
• in stressful situations, our body is adapted to..

  fight or flight
• why is adrenaline released in times of fear

  more glucose is delivered to the muscles so more energy is released through respiration in the muscles

  the effects of adrenaline allow the body to prepare for action in situations where a quick response may be needed
• the effect of adrenaline on the body

  -adrenaline binds to receptors in the heart which then contract more frequently and with more force

  -heart rate and blood pressure increase

  -adrenaline also binds to receptors in the liver which then breaks down glycogen stores to release glucose

  -this causes blood glucose levels to increase so that more glucose can be transported to cells for increased respiration
• negative feedback

  the body detects the level of a substance to be above or below the normal level, it then triggers a response to bring the level back to normal again
• thyroxine

  released by the thyroid gland

  increases metabolic rate, increases respiration rate, increases formation of proteins, lipids and glycogen

  release triggered by TSH, when levels get too high negative feedback occurs
• parts of the female reproductive system

  oviduct, ovaries, uterus, cervix, vagina
• progestrone

  maintains uterus lining

  inhibits FSH and LH for most of cycle

  stimulates FSH and LH release pre-ovulation
• oestrogen

  thickens uterus lining

  inhibits LH and FSH
• FSH

  stimulates follicular growth in the ovaries

  stimulates oestrogen secretion from follicles
• LH

  surge cause ovulation

  results in formation of corpus luteum
• menstruation

  the periodic discharge of blood and muscosal tissue from the uterus and vagina
• ovulation

  the phase of the menstrual cycle in which a mature ovum is released from the ovarian follicles in the oviduct
• four stages of the menstrual cycle

  day 1 is when menstruation starts, the uterus lining breaks down and is released

  the lining of the uterus builds up again, from day 4 to 14 into a thick, spongy layer full of blood vessels ready to release a fertilised egg

  an egg develops and is released from an ovary (ovulation) at day 14

  the lining is then maintained from about 14 days until day 28, if no fertilised egg has implanted by day 28 the spongy lining starts to break down and the cycle starts over
• contraception

  the deliberate use of artificial methods or other techniques to prevent pregnancy as a consequence of sexual intercourse
• injection

  uses progestrone

  progestrone thickens the muscus in the cervix stopping the sperm from reaching an egg, also thins the uterus lining to prevent implantation and can prevent release of an egg

  more than 99% effective

  lasts for upto three months
• implant

  uses progestrone

  progestrone thickens the muscus in the cervix stopping the sperm from reaching an egg, also thins the uterus lining to prevent implantation and can prevent release of an egg

  more than 99% effective

  lasts for upto three years
• IUS

  uses progestrone

  progestrone thickens the muscus in the cervix stopping the sperm from reaching an egg, also thins the uterus lining to prevent implantation and can prevent release of an egg

  more than 99% effective

  works for 3-5 years
• mini pill

  uses progestrone

  progestrone thickens the muscus in the cervix stopping the sperm from reaching an egg, also thins the uterus lining to prevent implantation and can prevent release of an egg

  more than 99% effective

  must be taken at the same time everday
• combined pill

  uses progestrone and oestrogen

  progestrone thickens the muscus in the cervix stopping the sperm from reaching an egg, also thins the uterus lining to prevent implantation and can prevent release of an egg

  more than 99% effective

  taken in a 21 day pill and 7 day no pill cycle
• patch

  uses progestrone and oestrogen

  progestrone thickens the muscus in the cervix stopping the sperm from reaching an egg, also thins the uterus lining to prevent implantation and can prevent release of an egg

  more than 99% effective

  lasts for a week
• sterilisation

  involves a surgical procedure to cut or tie the tubes in the reproductive system

  in women eggs are prevented from travelling from ovaries to uterus and in men it prevents sperm from being ejaculated

  more than 99% effective
• IUD

  device with copper thread inserted in the uterus that prevents sperm surviving and reaching an egg, also makes implantation difficult

  more than 99%
• natural methods

  sex is avoided when the women is most fertile or the penis is withdrawn prior to ejaculation

  least effective
• barrier

  male condom - worn over penis to prevent entry of sperm into vagina

  female condom - worn inside the vagina

  diaphragm - fits over the cervix to stop sperm meeting the egg, used with spermicide

  98% effective
• infertility

  failure to achieve pregnancy - you are considered infertile if conception has not occured after 12 months of sexual activity with no contraception
• male reasons for infertility

  sperm issues

  sperm mobility

  poor semen quality

  blocked tubes and sperm ducts
• female reasons for infertility

  ovary doesnt produce eggs

  follicle does not mature

  vagina too hostile too allow sperm to enter

  blockage of oviduct

  uterus lining not developed enough for implantation
• hormonal imbalance

  an inability to regulate hormone levels

  can cause production of too much or too little hormone

  irregular menstruation, abnormal bleeding, weight gain/loss, absence of menstrual period
• FSH treatment

  injections of FSH to stimulate follicular development
• IVF

  an egg is removed from the ovary and fertilised with sperm in a lab, the fertilised egg is then returned to the uterus to grow ad develop
• egg donation

  a donor provides an egg
• surrogacy

  another woman carries and gives birth to your child
• ovary transplant

  doctors transport healthy ovaries from a donor