The menstrual cycle starts in girls shortly after puberty, around 12 years of age for most people and is a good example of interactions between the nervous system and several hormones. This can be a painful experience for some girls but for others can be a relatively painless thing that is a minor "inconvenience" to them. The surrounding environment can affect the timing of menstruation, in some convents all women have their period at the same time, how much stress the person is under or even the diet they are taking is known to affect it. The cycle for a human takes around 28 days but in other mammals this could occur only once or twice a year in which they are said to be "on heat.".
So, assuming the cycle is twenty-eight days, when do we decide what is the starting of the new cycle and the end of another? It is usually customary in medical practice to consider the first day of menstruation as the first day of the new cycle, however most biologists prefer to regard the end of the bleeding as the start of the new cycle. Only once this shedding of the old lining of the uterus has finished then a new cycle can begin in the woman.
What happens to begin with is that the hypothalamus initiates the cycle at about day 4 by secreting gonadotrophins that starts the production of FSH, follicle stimulating hormone, and LH, Luteinizing hormone, from the anterior pituitary. The role of these two hormones are as follows: FSH initiates the development of several primary follicles, each containing a primary oocyte, of which one will develop further and the others will stop growing ready for next time. As well as this it stimulates the production of the ovarian hormone estrogen from the stroma of the follicles, whose function shall be explained in due course. LH job is to make the graafian follicle ovulate and to produce the corpus luteum, which too has a large role to play later on in the cycle.
As the graafian follicle grows it will begin to secrete more and more estrogen, whose job is to heal and repair the uterine lining after menstruation.
Domestic violence is in majority a learned behavior cycle. ... Politics plays a huge role in the continuing cycle of domestic violence. ... All of those also top the list for prevention and breaking the cycle. ... Educating people on the cycle, warning signs, and ways to seek help is mandatory to break up this vicious cycle. ...
The water cycle and the rock cycle are interrelated since they are both important factors to our earth. They also interrelate because the rock cycle needs part of the water cycle during erosion and weathering. ... The water cycle uses rocks and the rock cycle uses water run-off. ... Microsoft Encarta Encyclopedia 2000 - Water Cycle, Rock Cycle 2. Compton's 99 Encyclopedia - Water Cycle, Rock Cycle 3. ...
In the first proposal, the plan focuses on the reducing of the expenses to in public transportation and the implement of cycling infrastructures that aims to improve the affordability and sustainability. ... In addition to increasing public transit affordability, the practicing of cycling infrastructure is also considered not practical and operative. In spite of the fact that cycling infrastructure is environmentally friendly, it is not effective to practice it for long-distance trips because it could be time-consuming. ... Given the fact above, investing in cycling infrastructure could be a ...
In this term paper, I have compared Rankine cycle with Carnot cycle, I have given the idea of the application of Rankine cycle in steam power plants and the methods to increase the efficiency of the Rankine cycle. ... RANKINE CYCLE The Rankine cycle is common cycle used in all steam power plants. In Rankine cycle, the working fluid undergoes a change of phase during the cycle. ... The simple Rankine cycle is the common cycle used in all steam power plants. ... Such modification in Carnot Cycle will result Rankine Cycle as shown in fig.3. ...
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Exegetical Paper Two (2nd Kings 5:1-6:1) The biblical passage I am doing this exegetical paper on appears to be one of those mystery passages that no one knows anything about. This passage is part of what many people call the Elisha cycle. This cycle is inserted into Kings in the middle of th...
The biblical passage I am doing this exegetical paper on appears to be one of those mystery passages that no one knows anything about. This passage is part of what many people call the Elisha cycle. This cycle is inserted into Kings in the middle of the reign of King Jehoram. The events mentioned ...
The business cycle is divided into four parts or phases. ... That is exactly how it is portrayed in the business cycle. ... The business cycle is a continuous process. ... The business cycle can be of any length. ... No two business cycle are alike though. ...
Every product undergoes a Product Life Cycle (PLC). Product life cycle consists of four stages, introductory stage, growth stage, maturity stage and decline stage. Each stage has its own characteristics regarding marketing objective, competition, product, price, promotion and place. The introduction...