Pregnancy process in usa,can u conceive 5 days before your period,pregnancy tips 28 weeks 3d - PDF Books

Item #5001L The Pregnancy & Birth chart presents a detailed overview of the process from conception to birth. An overview of the reproductive processThe female reproductive system is a wonderfully complex system involving continuous communication between the brain centers and the ovary. The hypothalamus is located centrally in the brain and communicates by way of an exchange of blood with the pituitary gland. GnRH stimulates (or causes) the pituitary gland to produce the hormone responsible for causing the release of FSH (follicle stimulating hormone) which starts egg (oocyte) development and causes the level of estrogen (the primary female hormone) to rise. When the level of estrogen is sufficiently high, it produces a sudden release of LH, usually around day thirteen of the cycle.
The cells in the ovarian follicle that are left behind after ovulation undergo a transformation and become the so-called corpus luteum.
The luteal phase, or second half of the menstrual cycle, begins with ovulation and lasts approximately 14 days (typically 12-15 days).
Under the influence of progesterone, the uterus begins to change its character, creating a highly vascularized bed for a fertilized egg. In order for a pregnancy to occur, three steps must be accomplished: 1) the sperm must be deposited and transported to the site of fertilization, 2) ovulation must occur, and 3) union between the sperm and egg must result. Following ejaculation, the semen forms a gel which provides protection for the sperm from the vagina.
During ovulation, this barrier becomes thinner and changes its acidity creating a friendlier environment for the sperm. Once the egg arrives at a specific portion of the tube called the ampullary-isthmic junction, it rests for another 30 hours. So, too, in the IVF process an embryo may begin to develop but not make it to the blastocyst stage (the first stage where those cells destined to become the fetus separate from those which will become the placenta). If you liked this post please buy me a cup of coffee to quench my thirstBe Sociable, Share!
Inside the uterus, the fetus is surrounded by a protective, fluid-filled bag known as the amniotic sac. From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited. The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.
The overall structure of the female reproductive system is illustrated with smaller images showing the zygote stages.
Hormones secreted by the hypothalamus, the pituitary, and the ovary are the messengers which regulate the monthly cycle. Luteinizing hormone (LH), the other pituitary hormone, aids in egg development and maturation and causes ovulation. This process of egg loss occurs at all times including before birth, before puberty, and while on birth control pills. This LH peak (surge) triggers a complex set of events within the follicles that result in the final maturation of the egg and follicular rupture with egg extrusion. In addition to estrogen, they now produce high amounts of progesterone to prepare the lining of the uterus for pregnancy implantation.
During this period, changes occur which will support the fertilized egg (embryo) should pregnancy result. The corpus luteum produces progesterone until about 10 weeks gestation, if a pregnancy occurs. The sperm must be capable of propelling themselves through the environment of the female vagina and cervix.
Once the sperm have entered the uterus, contractions propel the sperm upward into the fallopian tubes. The blastocyst may implant but not grow or the blastocyst may grow and still cease development before the two-week time at which a pregnancy can be detected.


If you are new here, you might want to subscribe to the RSS feed for updates on this topic.Now this is something interesting!!! If you continue, we’ll assume you are happy for your web browser to receive all cookies from our website. Nourishment is provided through the placenta, an organ attached to the wall of the uterus and connected to the fetus by the umbilical cord.
In human beings it is approximately 9 months ± 7 days.The duration of pregnancy in dogs, elephants and cats is 63, 624 and 63 days respectively. The one which is most important for reproduction is called gonadotropin releasing hormone or better known as GnRH. The rupture, called ovulation, takes place 28-48 hours after the onset of the LH surge and 10-12 hours after LH reaches its peak. The hormone responsible for these changes is progesterone and it is manufactured by the corpus luteum. Otherwise if no embryo implants, the circulating levels of hormone decline with the degeneration of the corpus luteum, the lining of the uterus (endometrium) degenerates, and bleeding results (menses). If no pregnancy develops, the endometrium is shed as a menstrual period about 14 days after ovulation.
This environment, which is under cyclic hormonal control, must be favorable to admit the sperm without destroying them.
Adhesive sites on the tube, which are located on the surface of the fimbriae, are responsible for egg pickup and movement into the tube. This period of rest in the tube appears to be necessary for full development of the fertilized egg and preparation of the uterus for receipt of the egg.
However, once the embryo reaches the blastocyst stage (approximately 6 days after fertilization), it hatches out of its zona pellucida (shell) and begins the process of implantation. The receptivity of the uterus and the health of the embryo are important for the implantation process.
You will se the entire pregnancy process from the beginning, fertilization and the end with childbirth in just 13 pictures!!!
As the fetus grows, the uterus increases in size and weight and gradually expands into the mother’s abdomen. Each trimester is shown graphically with an overall view and a close-up view of the developing fetus. As the levels of FSH and LH in the blood increase with puberty, the eggs begin to mature and a collection of fluid (the follicle) begins to develop around each. These hormones in turn stimulate the growth of several ovarian follicles (each containing one egg). Finally, the sperm must possess the capability of converting to a form that can penetrate the cell membrane of the egg (capacitation).
A membrane (shell) surrounding the egg, the zona pellucida, has two major functions in fertilization.
Many of the mother’s organs, such as the bladder and the intestines, are pushed out of their normal positions by the enlarging uterus. The number of follicles in the “cohort” of developing follicles each month is unique to each individual.
The protected sperm with the greatest motility travel through the layers of cervical mucus that guard the entrance to the uterus. First, the zona pellucida contains sperm receptors which are species specific (specific for human sperm). It consists of foetal part, the chorion and a ma­ternal part the decidua basalis.The foetal part of placenta grows to invade the uterine mucosa with its chorionic villi. Second, once the membrane has been penetrated by the sperm it becomes impermeable to penetration by other sperm. The degree of inti­macy is so strong that the blood vessels of the chorionic villi are bathed in the mother’s blood.


This is due to erosion of the uterine mucosa, including its epithelium, connective tissue and the endothelial lining.This type of placenta which is based on the intimacy between foetal and maternal parts of the placenta, is referred to as haemochorial placenta. The placenta is connected to embryo through an umbilical cord which helps in the transport of substances to and from the embryo.
All the nutritive elements from the maternal blood pass into the foetus through the placenta, (ii) Respiration.
Oxygen passes from the maternal blood to the foetal blood through the placenta, and carbon dioxide passes in the reverse direction, (iii) Excretion.
The foetal excretory products diffuse into the maternal blood through placenta and are excreted by the mother, (iv) Storage.
Placenta serves as an efficient barrier and allows those materials to pass into the foetal blood that are necessary. Relaxin facilitates parturition (act of birth) by softening the connective tissue of the pubic symphysis.In addition, the levels of hormones like oestrogens, progestogens, cortisol, prolactin, thyroxine, etc. Neural tube deve­lops, the beginning of the brain and spinal cord (first oragans).Week 4Heart, blood vessels, blood and gut start forming. Umbilical cord developing.Week 5Brain developing, ‘Limb buds’, small swellings which are the beginnings of the arms and legs.
Beginnings of hands and feet.By week 12Foetus fully formed, with all organs, muscles, bones, toes and fingers.
At the end of the pregnancy vigorous contraction of uterus causes delivery or expulsion of the foetus.
The signals for child birth (parturition) originate from the fully matured foetus and placenta which induce mild uterine contractions called foetal ejection reflex. The amount of oxytocin is increased just before and during “labour pains” (pains of child birth).Childbirth begins with a long series of involuntary contractions of the uterus experienced as labour pains.
Relaxin increases the flexibility of the pubis symphysis and ligaments of the sacroiliac and sacrococcygeal joints and helps dilate the uterine cervix during labour pains. Both of these actions give relief to the body from the pain during delivery of the baby.The hormone most recently found to be produced by the placenta is corticotro- pin-releasing hormone (CRH), which in nonpregnant women is secreted only by neuro­secretory cells in the hypothalamus. CRH is now thought to be part of the “clock” that establishes the timing of birth.Secretion of CRH by placenta increases enormously toward the end of pregnancy.
During this stage, regular contractions of the uterus, usually rupturing of the amniotic sac and complete dilation of the cervix occur. Secretion and storage of milk generally begins after birth of young one, usually within 24 hours under the influence of hormone prolactin (PRL) secreted by anterior lobe of the pituitary gland. This is yellowish fluid that contains Cells from the alveoli and rich in protein (lactalbumin and lactoprotein) but low in fat.
Its main constituents are fat (fat droplets), casein (milk protein), lactose (milk sugar), mineral salts (sodium, calcium, potassium, phosphorous, etc.) and vitamins. Vitamin С is present in very small quantity in milk.The process of milk secretion is regulated by the nervous system. The process of milk production is also influenced by hormones of the pituitary gland (already mentioned), the ovaries and other endocrine glands. If the mammary glands are not fully emptied, the peptide accumulates and inhibits milk production.
Abortion: It is giving birth to an embryo or foetus prior to the stage of viability at about 20 weeks of gestation (foetus weighs less than 500 gm).



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