The human body is made up of about 30–40 trillion cells. Each cell is specialised to carry out a particular job. Cells work together to form co-ordinated units called tissues, organised into organs. This complicated organisation of cells that makes up a human being all originated from a single fertilised cell – the zygote. Embryology is the study of the development of the zygote in the first trimester - this podcast is deigned to be a short introduction to this fascinating area of Biology. (With thanks to our sponsor 'Curriculum Press' for providing content for this podcast)