Conception, Fetal Development & Genetics Flashcards
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
Placenta: progesterone
Nutritive for blastocyst
Development of endometrium for implantation
Decreases contractility of uterus
Placenta: prolactin
Important role in lactation
Human placental lactogen
Stimulates changes in what
Can cause what
Stimulates changes in maternal metabolism
Can cause insulin resistance leading to gestational DM
Placenta: relaxin
Softens ligaments and cartilage in skeletal muscles
Quiets the myometrium (prevents it from contracting during pregnancy0
Placenta name for baby side vs mom side
Baby: shiney shultz
Mom: dirty dunken
Umbilical cord
Connects what
Contains what vessels
Insertion of cord should be what
Check cord at birth for vessels
Check for what
Connects embryo/fetus to placenta
Contains 1 large vein and 2 small arteries (AVA)
Cord should be center of the placenta
Check for nuchal cord (around neck)
Check for knots (might have nots in cord)
Fetal circulation (know where)
Placenta
One umbilical vein (oxygenated blood)
Ductus venosus
Foramen ovale (between atrium)
Ductus arteriosus
Two umbilical arteries (unoxygenated blood)
Pulmonary pressure is what vs systemic pressure
Pulmonary pressure is high
Systemic pressures low
This is why the blood shunts thru foramen ovale and skips the ventricles and lungs
In case where it goes to ventricles it will shunt thru ductus arteriosus in the pulmonary artery.
Milestones in fetal development
8-12wks
20wks
22wks
28wks
32wks
36wks
8-12: FHR with doppler
20: quickening (movement) sooner with multiple pregnancy
22: earliest point of viability (production of surfactant)
28: more developed respiratory system
32: sucking reflex
38: survival with little support
Lung maturation (surfactant)
When its produced
What happens when further in gestation
What does it do
22 wks surfactant is starting to be produced
Further in gestation more surfactant is produced
Surfactant prevents alveoli from sticking together by reducing surface tension and coats the alveoli
Toxoplasmosis
Teach avoid raw/rare meat and cat litter
Cause: blindness, cognitive impairment
Chromosomal abnormalities do not follow what?
Patterns of inheritance
AFP alpha-fetoprotein
Indicates
Neural tube defects
Down syndrome
Amniocentesis
Drawl out amniotic fluid
Chorionic villi sampling
Thru vaginal or abd drawl fluid
Fetal nuchal translucency
What is
Indication
Ultra sound
Trisomies (including downs syndrome)
Cell-free fetal DNA
What it is
Indication
Draw moms blood
Tells us:
Fetal sex
Some trisomies
FSH (follicular secreting hormone)
Bleeding
Days: 1-14
Primary/secondary/graafian follicle
LH (luteal hormone)
Days: 14-28
Imature follicle released to fallopian tube
Ovulation and corpus luteum
