Lecture 36- Fetal Period Flashcards
What is the first organ system to function?
Cardiovascular system (heart forms and begins to beat at week 4)
What happens at week 5-8?
Limbs start becoming clear, heart 4 chambered
Bone formation begins
External genitalia begins to differentiate
Fetal period is mainly characterized by?
Body growth
Maturation of of organs
Embryonic period is mainly characterized by?
Tissue differentiation
Formation of organs
Rapid body growth
What is the earliest period the fetus can be born prematurely and live?
Week 25+
What happens in week 9-12
Fetal length nearly doubles
Heartbeat can be detected
Gender can be assessed by looking at external genital
When does the fetus assume upside down position?
Week 30-34
What is the body fat % of fetus before birth?
16% (8% in weeks 30-34)
What is the weight of fetus before birth?
3200-3400g
Placenta is a fetomaternal organ with 2 components
Fetal (develops from x)
Maternal (develops from y)
Fetal develops from villous chorion
Maternal develops from decidua basalis (part of endometrium lining)
As the fetus grows,the chorionic cavity x, and for amniotic cavity y, degrading thr
The chorionic cavity disappears, and the amniotic cavity expands, degrading the desidua capsillaris
What is the primary function of the placenta?
Serve as an organ for exchange between the concepts and mother
Do the maternal and fetal blood directly mix?
No
Give eg’s of nutrients that enters the fetus from the endometrial spiral arteries
Water Carbs (glucose) Amino acids Lipids Electrolytes Harmones Vit’s Iron
Give ex’s of substances that leave the fetus through the umbilical arteries
Waste products like: CO2 Water Urea Uris acid Bilirubin Other substances: RBC antigens Harmones
T/f the umbilical arteries carry oxygenated blood from the fetus’s heart to the chorion
False
The umbilical arteries Carry DEOXYGENATED blood
What’s the function of HcG harmone?
It is a harmone secreted by the placenta Rescues the corpus luteum so that it continues to produce progesterone and some estrogen to Maintain endometrium lining Prepare mammary glands for lactation Prepare mother’s body for birth
What is the function of relaxin?
A harmone secreted by the placenta
- Increases flexibility of the pubic symphysis (easier to undergo labor)
- Helps dilate the uterine cervix during labor
What is the funding
Function of Human chorionic somatomammotropin hCS
Helps prepare the Navarre glands for lactation
Enhances growth by increasing protiens synthesis
Decreases glucose used by the mother and increases fat acid use by mother for ATP ( leave glucose to the fetus)
What is the function of Corticotropin releasing harmone?
Establishes the timing of birth
Increases section of cortisol TO MATURE THE LUNGS!
Describe the placenta
A discoid structure with a diameter of 15-25cm
Thickness of about 3cm
Weirgr 500-600gm
Maternal side exhibits 15-20 cotyledons (bumpy part) separated by decidual septa
Fetal surface covered by amnion
When is the placenta expelled?
Approx 30 min after birth
What is placenta previa?
Placental abnormality where the placenta is implanted lower end of the uterus (close to cervix)
Birth will be very bloody; C section os usually advised
What is placenta accreta?
Placental abnormality where the villi will adhere superficially to the muscle wall (myometrium)