Week 1 Flashcards
Process of male gametogenesis
Type A spermatogonia (stem cells) through mitosis to Type A spermatogonia (progenitor cells) through mitosis to Type B spermatogonia. Type B spermatogonia through mitosis to primary spermatocyte through meosis to secondary spermatocyte through meosis to spermatid. Spermatid will go through spermiogenesis (differentiation) until they reach mature spermatozoa
Process of female gametogenesis
Oogonium through mitosis to primary oocyte (arrested in prophase I); primary oocyte through meiosis to secondary oocyte (arrested in metaphase II); if fertilized secondary oocyte to ovum through meosis II
gravida
- number of times female has been pregnant; regardless of pregnancy outcome
- twin pregnancy counts as one
parity
- number of pregnancies reachingviable gestational age(including live births and stillbirths).
- number of fetuses does not determine the parity;Twin pregnancy carried to viable gestational age is counted as 1.
gestation
the process of carrying or being carried in the womb between conception and birth.
Relate advanced maternal age to occurrence of chromosomal abnormalities and miscarriages
- cohesin and securin are proteins present that help keep chromosomes together at their centers.Lower levels of these proteins cause the chromosome pairs or sister strands to be more loosely connected and further apart.
- Researchers found that older female mice had lower amounts of these proteins in their eggs, suggesting thatas the eggs age, the levels of these proteins fall.
- leads to instability in the chromosome pairs and a higher likelihood that chromosome division will happen unevenly.The result could lead to an increased chance of older mice having offspring with an abnormal number of chromosomes.
mechanisms that cause chromosomal abnormalities
- aneuploidy due to non-disjunction
- aneuploidy due to anaphase lag
aneuploidy due to non-disjunction
non-disjuction occurs during first meotic split
aneuploidy due to anaphase lag
non-disjuction occurs during second meotic split
Down Syndrome (trisomy 21)
- light or severe degree of intellectual disability and a number of physical features. -develop less quickly, both physically and mentally.
- Many babies with Down syndrome die during pregnancy.
- 50% are born with cardiac abnormality and/or other abnormalities. Cardiac abnormality can be treated surgically depending on the nature and severity of the abnormality.
Edwards syndrome (trisomy 18)
- Most die during pregnancy or shortly after birth.
- Most children die in the first year of their lives.
- have severe mental retardation.
- 9 out of 10 children have a serious congenital heart defect.
PatauSyndrome (trisomy 13)
- most die during pregnancy or shortly after birth.
- Most children die in the first year of their lives.
- severely mentally retarded; brains and the heart fail to develop properly; Kidney defects and abnormal gastrointestinal tracts may also occur.
- may develop more fingers or toes.
- cleft lip and palate.
Noninvasive Prenatal Testing (NIPT
new, optional non-invasive evaluationthat combines a maternal blood screening test with anultrasoundevaluationof the fetus to identify risk for specific chromosomal abnormalities,includingDown Syndrome Trisomy-21 and Trisomy-18.
Quad screening test
- AFP:alpha-fetoproteinis a protein that is produced by the fetus
- hCG:human chorionic gonadotropinis a hormone produced within the placenta
- Estriol:estriolis an estrogen produced by both the fetus and the placenta
- Inhibin-A:inhibin-Ais a protein produced by the placenta and ovaries
karyotyping
- test to examine chromosomes in a sample of cells. This test can help identify genetic problems as the cause of a disorder or disease.
- can use amniotic fluid, blood, bone marrow, or placenta to extract cells
- cells are grown and then stained, microscope used to examine the size, shape, and number of chromosomes in the cell sample, sample is photographed to show the arrangement of the chromosomes.