Human biology

• What are male gametes called?

  sperm cells.
• What are the female gametes called?

  Egg (ovum - ova for plural).
• Where is sperm produced?

  Seminiferous tubules.
• Where is testosterone produced?

  Interstital cells.
• Why do sperm need fluid to swim?

  The fluid provides energy for the sperm and maintains the mobility and viability as it swims towards the oviduct.
• What is a follicle?

  A fluid filled sac that surrounds the ova, it releases hormones.
• What connects the ovaries to the uterus?

  Oviducts (fallopian tubes).
• What is a zygote?


  When sperm fertilises an egg it becomes a zygote then matures into an embryo.
• How many chromosomes are there in sperm and ova?

  23 chromosmes.
• What hormones are released in female puberty?

  Follicle stimulating hormone (FSH) and Luteinising hormone (LH).
• What hormones are released in male puberty?


  Luteinising hormone (LH) and Interstitial cell stimulating hormone (ICSH).
• How does Interstitial cell stimulating hormone (ICSH) effect male puberty?

  ICSH stimulates the testes to produce testosterone, this causes the development of male sex organs and secondary sex characteristics.
• How does Luteinising hormone (LH) effect female puberty?

  LH stimulates the ovaries to produce oestrogen, this causes the development of female sex organs and secondary sex characteristics.
• What is the role of FSH in males?

  FSH stimulates seminiferous tubules to produce sperm.
• What is the role of ICSH in males?

  ICSH stimulates interstitial cells to release testosterone.
• How does negative feedback control the release of testosterone?

  Build up of testosterone concentration inhibits the secretion of FSH and ICSH from the pituitary gland.

  Reduction of FSH and ICSH results in a drop in production of testosterone.

  Reduction of testosterone concentration stops inhibition of FSH and ICSH production.

  The production and release of FSH and ICSH increases, stimulating increased production of testosterone.
• What is ovulation and when does it occur?


  A mature egg is released from the ovary to travel through the oviduct to the uterus, if it doesn't meet a sperm it will trigger menstruation.
• How does hormones influence menstruation?

  Day 1 of the menstrual cycle bleeding occurs due to the loss of the uterine lining, this causes a drop in progesterone levels.

  By day 5-7 the loss of blood is stopped and there is an increase in oestrogen to repair the uterine lining.
• What is oesteogen responsible for in females?


  Responsible for repairing and thickening the lining of the uterus.
• What is progesterone responsible for in females?

  Responsible for maintaining the thickness of the uterine lining.
• What is FSH responsible for in females?

  Causes an egg to mature in the ovary, stimulating the ovaries to release oestrogen.
• What is LH responsible for in females?

  Triggers the release of a mature egg (ova) / triggers ovulation.
• Why are males continously fertile?

  Levels of FSH ICSH are kept relatively constant through negative feedback, as a result sperm are produced continously.
• Why are females only cyclically fertile?

  Levels of oestrogen, progesterone, FSH and LH fluctate, as a result women are only fertile for a few days before ovulation and during their menstural cycle.
• What are three ways fertility can be identified in a female?

  Slight increase in body temperature after ovulation.

  Cervical mucus may become clearer, wetter and more slippery around ovulation.

  Timing of menstural cycle, ovulation typically occurs 10 to 16 days after a period occurs.
• Why may a female be infertile?

  If a women does not produce enough FSH and LH naturally.
• How can drugs help a women ovulate/be fertile?


  They can prevent the negative feedback effect of oestrogen and FSH.

  They can mimic the normal action of FSH and LH to stimulate ovulation.
• What can artifically stimulating ovulation lead to?

  Multiple births, as more than one egg may be released.
• What is artificial insemination?

  A sample of sperm is treated to remove dead sperm and slow sperm. Healthy sperm is then passed into the uterus via a catheter. A donor may also be used.
• Why would artificial insemination be used?

  A man has a low sperm count.

  A couple are unable to have vaginal intercourse.

  A condition (such as a virus) meaning that a couple needs help to conceive.

  A donors sperm is being used a same sex couple.

  When a mans sperm in sterile.
• What is intracytoplasmic sperm injection (ICSI)?


  A sample of sperm is collected and the head of the sperm is drawn into a needle to be injected into the egg directly to increase the chances of fertilisation.
• Why would intracytoplasmic sperm injections be used?

  Low sperm count.

  Mature sperm are abnormally shaped or don't move normally

  Where sperm needs to be remove surgically.

  Frozen sperm that had reduced in quality is being used.
• What is in vitro fertilisation (IVF)?


  The removal of one or more eggs from a womens ovaries which are then fertilised with sperm in a labatory.
• Why would IVF be used?

  There are issues with the quality of a mans sperm.

  A women has blocked oviducts.

  Where one or both partners may pass on a serious genetic condition.

  Where a donor sperm or donor eggs are being used.
• What is pre-inplantation genetic diagnosis?


  If one or both partners are at risk of passing on a serious genetic disorder, PGD can be used to check for single gene disorders and chromosome abnormalities in developing embryos before they are implanted into the uterus.
• What are some examples of physical contraception?

  Condoms, intrauterine devices (IUD), surgery.
• What are some examples of chemical contraception?

  Oral contraception pill - mix of oestrogen and progesterone that mimics the natural negative feedback effect to prevent the release of FSH and LH.

  Mini pill - progesterone only, causes thickening of cervical mucus.

  Morning after pill - contains a stronger dose of oestrogen and progesterone than the contraceptive pill, prevents/delays ovulation.
• What is antenatal screening?


  Used to identify any possible risks to the mother or foetus during pregnancy or to identify health issues that will affect the baby.
• What is a dating scan?

  Carried out between 8 and 14 weeks of pregnancy to determine stage of pregnancy and determine expected due date.
• What is an anomaly scan?

  Carried out between 18 and 20 weeks of pregnancy, may detect any serious physical abnormalities of the foetus.