Conception, Fetal Development & Genetics Flashcards
(43 cards)
How long is a mentrual cycle and when does ovulation occur
Mentraul cycle is 28 days
Ovulation occurs 14 days prior to menses (bleeding)
Signs of ovulation
Increase basal body temperature
Pain over ovary
Cervical mucus becomes clear, slippery, stretchy
Once ovulation occurs how long is ovum and sperm viable
Ovum is viable for 24 hrs
Sperm 48-72hrs
Where does fertilization occur usually
Outer third portion of fallopian tube
Zygot ( resulting structure) produces what and helps with what
Produces HCG which helps maintain the corpus luteum until implantation
What is the corpus luteum?
Where the ovum is release from in the ovary
Produces estrogen and progesterone to prepare endometrium for implantation
Implantation of trophoblast (outer cell of zygot) occurs when and where
What it produces
7-10 days upper posterior uterus
Produces HCG until placenta fully functioning
Dizygotic
Fraternal
Two ovum
Two sperm
Two zygotes
Have 2 amnions
Have 2 chorions
Monozygotic
Identical
One fertilized ovum splits (DNA splits)
May have:
Mono/mono (share placenta and sack)
Mono/di (own sack share a placenta)
Di/di (own sack and placenta)
Stages of fetal development
Zygotic stage
Blastocyst stage
Embryonic stage
Fetal stage
Zygotic stage
Fertilization of sperm and egg (conception)
Blastocyst stage
Zygote divides into a solid ball of cells and attaches to the uterus
Embryonic stage
End of the 2nd week thru eighth week
Fetal stage
Differentiation and structures specialized by end of the eighth week until birth
Once impanted called a what
After 8 weeks becomes what
What is most risk from in embryonic stage
What happens end of 8th week
Fetal period
Once impanted called embryo
After week 8 called fetus
Most risk from teratogens
End of 8th week organ systems are present and refinement of systems occurs
Fetal:9-40wks
40 week gestation break down
Gestation starts on 1st dat of last menstrual cycle
3 trimesters of 13 weeks
Trimesters:
1: 0-12 weeks
2: 13-27 weeks
3: 28-40 weeks
Chorion
Outermost layer
Fingers called chorionic villi which assist in attaching and implanting into uterus. Gives way to the placenta
Amnion
Fuses with chorion to become amniotic sac
Inner protective membrane contains the embryo and amniotic fluid
Amniotic fluid
At term
Polyhydramnios
Oligohydramnios
At term: 700-1000ml
Poly: >2000ml (caused by GI problems)
Oligohydramnios <500ml (caused by renal, poor placental perfusion)
Amniotic fluid functions (6)
Cushion/ shield against pressure
Control temp
Allow for symmetrical growth & development
MSK development
Protect against cord compression
Keep membranes from adhering to fetal parts
Placenta
Functioning by when
Amount of layers of cells between mom/fetal circulation
Provides what exchange
Immunologic properties
Why is it an endocrine gland?
By 3rd week
One layer (so their blood never mixes)
Metabolic and nutrient exchange
IP: prevents rejection of new genetic material
Produces hormones from pregnancy
Placenta as endocrine gland: what hormones
HCG
Estrogen
Progesterone
Prolactin
Human placental lactogen
Relaxin
Placenta: HCG
Present where and when’
Max amount at how many days vs lowest
Stays high until when
Present in serum(blood) 8-10 days after fertilization
Present in urine at missed menses
Amount:
Max 50-70 days then declines to lowest 100-130 days
Stays high until placenta is fully functioning and produces its own estrogen and progesterone
Placenta: estrogen
Growth in uterus, breast
Increased vascularity, and vasodilation
