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October, 2006
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Menstrual Cycle: The period from onset of one menstrual bleeding (Menstruation) to the next in an ovulating woman or female primate. The menstrual cycle is regulated by endocrine interactions of the Hypothalamus; the Pituitary gland; the ovaries; and the genital tract. The menstrual cycle is divided by Ovulation into two phases. Based on the endocrine status of the Ovary, there is a Follicular phase and a Luteal phase. Based on the response in the Endometrium, the menstrual cycle is divided into a proliferative and a secretory phase.


JoVE 10906

In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from the equivalent procedure of spermatogenesis in males. First, meiotic divisions during oogenesis are asymmetric, meaning that a large oocyte (containing most of the cytoplasm) and minor polar body are produced as a result of meiosis I, and again following meiosis II. Since only oocytes will go on to form embryos if fertilized, this unequal distribution of cell contents ensures that there are enough cytoplasm and nutrients to nourish the early stages of development. Second, during oogenesis, meiosis “arrests” at two distinct points: once during embryonic growth and a second time during puberty. In mammals, oocytes are suspended in prophase I until sexual maturation, at which point meiosis I continues under hormonal influence until an egg precursor cell is released into a fallopian tube. At ovulation, the precursor exits the ovary and, only if fertilization occurs, is stimulated to complete meiosis II and form a complete egg. Defects during oogenesis can result in severe consequences. In particular, problems with chromosome segregation during either meiosis I or meiosis II may lead to an embryo being aneuploid, meaning that it contains an abnormal number of chromosomes. Increased age elevates a woman

 Core: Biology

Pelvic Exam III: Bimanual and Rectovaginal Exam

JoVE 10163


Alexandra Duncan, GTA, Praxis Clinical, New Haven, CT

Tiffany Cook, GTA, Praxis Clinical, New Haven, CT

Jaideep S. Talwalkar, MD, Internal Medicine and Pediatrics, Yale School of Medicine, New Haven, CT

A bimanual exam is a…

 Physical Examinations II

Conscious and Non-conscious Representations of Emotional Faces in Asperger's Syndrome

1Institute of Statistical Science, Academia Sinica, 2Max Planck Institute for Human Cognitive and Brain Sciences, 3Department of Psychology, Fo Guang University, 4Department of Electrical Engineering, Fu Jen Catholic University, 5State Research Institute of Physiology and Basic Medicine, 6Novosibirsk State University, 7Imaging Research Center, Taipei Medical University

JoVE 53962

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