Elements & Compounds Elements are substances made from one kind of atom Compounds are made from two or more elements chemically combined Elements take part in chemical reactions in which new su...
Annotating the Seminiferous Tubule and Ovary Annotating the Seminiferous Tubule The testes contain many small tubes, or tubules, known as seminiferous tubules The production of sperm, or spermatoge...
Assessing the Risks of Oestrogen Pollution NOS: Assessing risks and benefits of scientific research: the risks to human male fertility were not adequately assessed before steroids related to proges...
The Placenta & the Exchange of Materials Mammals can be split into different categories on the basis of their mechanism for foetal nourishment Placental mammals, such as humans Monotremes, or e...
Role of hCG in Early Pregnancy Shortly after the developing embryo implants into the endometrium it begins secretion of the hormone human chorionic gonadotropin (hCG) hCG is secreted during the fir...
Implantation of the Blastocyst Following human fertilisation, the newly fertilised ovum divides by mitosis to form two diploid nuclei (i.e. each nucleus contains two sets of chromosomes) and the cy...
Preventing Polyspermy Fertilisation is the fusion of one sperm cell and one ovum; this fusion of two haploid nuclei gives rise to a diploid zygote During sexual reproduction, many sperm are release...
Similarities Between Oogenesis & Spermatogenesis Sexual reproduction involves fertilisation; the fusion of sex cells, or gametes, from two parents Gametes are specialised, haploid cells The fus...
Drawing the Human Kidney The following elements should be included in a drawing of the human kidney The kidney should be roughly oval in shape with an inward curve on the side where it is connected...
