Chapter 6 - Conception and Prenatal Development Flashcards
Gametes =
Somatic cells =
Gametes = sex cells.
Somatic cells = body cells.
Mitosis = def
diploid number of chromosomes (46)is retained in the new cell
Meiosis - what happens?
23 chromosomes (not all, half) are made.
Oogenesis - def
formation of female gametes
Primary oogonium begins its first meiotic division during fetal life but doe snot complete the process until ____
Puberty
By the 30th week of gestation, the female fetus has all the ova she will ever have. T/F?
True
What is spermatogenesis?
The formation of sperm
Sperm determines the sex of the baby. T/F?
True
Before ovulation, several oocytes begin to mature under the influence of FSH and LH. T/F?
True
Sperm - they don’t go through any changes once they enter the vajeen. T/F? What is it called?
FALSE - they have to go through some changes, called capacitation.
When is the pre-embryonic period?
First 2 weeks after conception.
Around the 4th day after conception, the fertilized ovum, now called a _____, enters the uterus.
ZYGOTE
What is the conceptus?
Cells and membranes resulting from fertilization of the ovum)
Morula - def?
12-16 cell stage of the fetus
What is the decidua?
Endometrium during pregnancy
Implantation and survival of the conceptus requires a continuing supply of __ and ___
Estrogen and progesterone.
The zygote secretes ___ to tell the woman’s body that she’s pregnant!
HCG
Normal implantation occurs in the __ uterus.
Upper
A small amount of bleeding can occur as the zygote implants…T/F?
True - which is why some women think they’ve actually had their period
Embryo - week __ to __
3-8
During the embryonic phase, structure are particularly at risk for harm by __
Teratogens - because they’re developing so fast!
Embryo’s develop - cephalocaudal, central to peripheral and simple to complex. T/F?
True
What is a full-term baby?
36-40 weeks of fertilization age or 38-42 weeks of gestational age.
Fertilization age - approximately 2 weeks longer than the gestational age. T/F?
FALSE - it’s shorter.
Implantation is complete by the end of the ___ week after fertilization.
2nd
The CNS begins developing during the __ week.
3rd
The primitive/tubular heart begins beating at day __ to __.
22-23
Neural tube closes during the ____ week - if not, problems occur.
4th
When is the fetal period?
9 weeks after conception and ends with birth.
Weeks 13-16 - what is quickening?
First fetal movements.
Weeks 21-24 - lungs are beginning to produce ___.
Surfactant - makes it easier to breathe.
Weeks 25-28 - baby starts to move head down. T/F/
True
Maternal and fetal blood typically don’t mix in the placenta, however……
They can! Like if there’s trauma, or during childbirth, etc.
Fetal HgB can carry 20-50% more oxygen than adult hemoglobin. T/F?
True
What is the bag of waters?
Two fetal membranes - the amnion (inner) and chorion (outer)
Amniotic fluid - about ___ ml by end of pregnancy.
700-800
Umbilical vein - action
Umbilical artery - action
Vein = brings oxygen and nutrient rich blood back to the placenta.
Artery - takes waste and such away from placenta, back to the mom.
What are the 3 blood shunts in the baby?
Ductus venosus, foramen ovale, ductus arteriosus.
What does the ductus venosus do?
Shunts blood away from the liver.
What does the foramen ovale do?
Shunts the blood through the heart - bypasses the lungs.
What does the ductus arteriosus do?
Shunts the blood from the aorta - we don’t need as much systemically.
Monozygotic twins are conceived by the union of a single ovum and spermatozum - T/F/
True
What are dizygotic twins?
Twins that arise from two ova and they are fertilized by two sperm.
