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Conception occurs when?
a single sperm from the male unites with an ovum(egg) in the females fallopian tube in a process called fertilization
how long is prenatal development?
When does it start and finish?
What are the 3 stages ?
- it is 266-280days, 38-40 weeks,
- Begins with fertilization and ends with birth
- Germinal, embryonic and fetal
The Germinal Period
- The period of prenatal development that takes place in the first two weeks after conception
- it includes the creation of the zygote(fertilized egg), continued cell division(mitosis) and the attachment of the zygote to the uterine wall
- takes place the first two weeks after conception
the inner layer of the cell that develops during the germinal period- these cells later develop into the embryo
- the outer layer of the cells that develops in the germinal period
- these cells provide nutrition and support for the embryo
The embryonic period
- the period of prenatal development that occurs two to eight weeks after conception
- the rate of cell differentiation intensifies
- support systems for the cells form
- organs appear
- umbilical cord
Three layers of cells that form during the embryronic period? what do they form?
- Endoderm-internal body parts(digestive/respitory)
- mesoderm-parts that surround the internal parts(bones/muscle)
- ectoderm surface parts(nervous system)
prenatal life support system that is a bag or envolope that contains a clear fluid in which the developing embryo flats
A life support system that contains two arteries and one vein and connects the baby to the placenta
Organ formation that takes place during the first two months of prenatal development
The fetal period
- last about 7 months(between 2month-birth)
- Rapid growth
- grasping reflexs
- irregular breathing movement
Which trimester do both germinal and embryonic periods occur?
Which trimester is the fetal period in?
End of first, second and third
When is the fetus viable?
as early as 6 months( very end of second trimester?
any agent that can potentially cause a birth defect or negatively alter cognitive and behavioral outcomes
What influences the severity of the damage to an embryo or fetus and type of defect from exposure to a particular teratogen?
- Dose(greater dose of an agent greater the effect)
- Genetic Susceptibility(Extent to which an embryo or fetus is vulnerable to a teratogen my depend on its genotype) males are more likely to be affected than female fetuses
- Time of exposure( Embryonic period is more vulnerable than the fetal period) Damage during germinal period may prevent implantation
When are teratogens are less likely to cause anatomical defects after what ?
parthenogenesis is complete , instead exposure during fetal period is more likely to instead stunt growth or create problems in the way organs function
Fetal alcohol spectrum disorder fasd
- a cluster of abnomalities and problems that appear in the offspring of mothers who drink alcohol heavily during pregnancy
- facial deformation
- below average intellegence
- mental retardation in some
Cesarean Delivery what and why?
Removal of the baby from the mothers uterus through an incision made in her abdomen
- If the baby is in breech position(buttocks are the first part to emerge from the vagina)
- Breech position can cause respatory problems as a result cd is preformed
- also can be preformed if contractions stop, cervix stops dilating or if mom has an illness like an std
Difficulties premature babies face ?
- more likely to develop learning disablities
- attentin deficit hyperactivity disorder
- breathing problems such as asthma
What the the 3 stages of labor?
- Labor begins when hormones changes cause contractions
- 1. Dilation- longest stage- contractions put pressure on the cervix, also put pressure on the baby which cause it to descend into the mothers pelvis
- 2.Expulsion-Cervix is completely dialted to 10cm, baby moves through the bone of the pelvic ring, through the cervix and into the vagina, baby tucks chin to exit easier/ soft bones of the skill actually over lap to fit through the pelvis
- 3. After Birth- 10-20mins after birth, placenta is delivered.
- EGG/OVA and Sperm are know as germ cells
- they are designed to combine with other germ cells in ordr to produce a brand new cell
- they are prepared for conception by a process of cell division called MEIOSIS