AHL Content Statements

• D3.1.13

  Control of the developmental changes of puberty by gonadotropin-releasing hormone and steroid sex hormones
  

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  Limit to the increased release of gonadotropin-releasing hormone (GnRH) by the hypothalamus in childhood triggering the onset of increased luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release. Ultimately the increased sex hormone production leads to the changes associated with puberty.

• D3.1.14

  Spermatogenesis and oogenesis in humans
  

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  Include mitosis, cell growth, two divisions of meiosis and differentiation. Students should understand how gametogenesis, in typical male and female bodies, results in different numbers of sperm and eggs, and different amounts of cytoplasm.
  

• D3.1.15

  Mechanisms to prevent polyspermy

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  The acrosome reaction allows a sperm to penetrate the zona pellucida and the cortical reaction prevents other sperm from passing through.
  

• D3.1.16

  Development of a blastocyst and implantation in the endometrium

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  Students are not required to know the names of other stages in embryo development.

• D3.1.17

  Pregnancy testing by detection of human chorionic gonadotropin secretion

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  Include the production of human chorionic gonadotropin (hCG) in the embryo or developing placenta and the use of monoclonal antibodies that bind to hCG.

• D3.1.18

  Role of the placenta in foetal development inside the uterus

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  Students are not required to know details of placental structure apart from the large surface area of the placental villi. Students should understand which exchange processes occur in the placenta and that it allows the foetus to be retained in the uterus to a later stage of development than in mammals that do not develop a placenta.

• D3.1.19

  Hormonal control of pregnancy and childbirth

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  Emphasize that the continuity of pregnancy is maintained by progesterone secretion initially from the corpus luteum and then from the placenta, whereas the changes during childbirth are triggered by a decrease in progesterone levels, allowing increases in oxytocin secretion due to positive feedback.
  

• D3.1.20

  Hormone replacement therapy and the risk of coronary heart disease

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  NOS: In early epidemiological studies, it was argued that women undergoing hormone replacement therapy (HRT) had reduced incidence of coronary heart disease (CHD) and this was deemed to be a cause- and-effect relationship. Later randomized controlled trials showed that use of HRT led to a small increase in the risk of CHD. The correlation between HRT and decreased incidence of CHD is not actually a cause- and-effect relationship. HRT patients have a higher socioeconomic status, and this status has a causal relationship with lower risk of CHD.

• B2.3.10

  Adaptations of sperm and egg cells
  

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  Limit to gametes in humans.