Fetal Development PPT Flashcards
Why do blastocyst secrete HCG?
To make sure the corpus lute remains viable
How long does the corpus lute secrete estrogen and progesterone?
First 2-3 months of pregnancy
What happens during the first weeks of human development?
Transport of embryo down uterine tube and into uterus
What is mitotic cellular replication?
Cleavage and occurs as baby (zygote) is propelled toward the uterus
How many cells in morula?
16
What is outer layer of cells of zygote?
Trophoblast
What are the inner layer of cells of zygote?
Blastocyst
What is the time period for when we refer to it as ovum?
Conception to day 14
What is the time period for when we refer to it as embryo?
Day 15 to 8 weeks
What happens in embryo period?
Organs are forming; greatest vulnerability
When do we refer to it as fetus?
8 weeks-birth
What all happens in the period when we refer to it as ovum?
This is when there is the cellular replication. It goes from zygote to blastocyst formation and has the differentiation into the 3 germ layers
Embryonic development stage: What are the 3 germ layers?
Ectoderm (outer)
Endoderm (inner)
Mesoderm (middle)
What germ layer is the trophoblast layer?
Ectoderm
What does ectoderm develop into?
Placenta
Integument
Neural tissue and glands
Nervous system
What does the mesoderm form into?
- Circulatory system
- Urinary and reproductive organs
- Muscles
- Bones
- CT
- Gentiourinary system
What does the endoderm form into?
- Thymus
- Thyroid
- Digestive, respiratory, and parts of the GU system
What is viability?
Capability to survive outside the uterus
What is the major criteria for viability?
CNS function and O2 capability of lungs
What is viability defined as?
Weight of 350, 400, or 500 g (varies by state) & 20 weeks past conception
In TN it is 20 weeks and 500 g
What do shunts allow?
Most oxygenated blood to go to the brain
Does maternal and fetal blood usually mix?
Not normally
What does ductus venosus do?
Shunts around the liver–placenta does the work of the liver for the fetus
What kind of shunt is a foramen oval? What does it do?
Right-left shunt; blood barrels right across from right atrium to left atria
What has the shunt around the lung?
Ductus arteriosus
The formation of blood
Hematopoiesis
Hematopoiesis: The formation of blood starting in the _____ (_____)
Yolk sac; (3rd week)
Hematopoietic: When do stem cells seed the liver function?
5th week
When does hematopoiesis begin ?
6th week
Hematipoietic: Stem cells seed the fetal bone marrow, spleen, thymus, and lymph nodes at _____
Week 8 and 11
What factors determine blood type and when are they present in the erythrocytes?
Antigenic factors determine blood type and are present in the erythrocytes around 5 weeks
What can we give if mom is Rh- and baby is Rh+?
Rhogam
When does blood cells and heart functioning start?
3 weeks
When is heart fully developed?
8 weeks
When is lung movement seen?
11th week
When are lungs fully mature?
34 weeks gestation
*just bc they have lung maturity at 34 weeks doesnt mean they know how to use the lungs…breathing (or the swelling of amniotic fluid) can be seen on an ultrasound
Two separate pregnancies occurring simultaneously
- 2 embryos
- 2 placentas
- 2 chorions
- 2 amnions
Dizygotic twins
Results from the division of a single fertilized ovum
- Same sex
- Same physical traits
Monozygotic twins
What is di/di twins?
2 embryos, 2 sac, 2 placentas
Each embryo has their own amniotic sac and their own placenta (fraternal)
What is mo/di twins?
2 embryos, 2 amniotic sac, 1 placenta
Each embryo has their own amniotic sac but share a placental (very unusual)
What is mo/mo twins?
2 embryos, 1 sac, 1 placenta
What type of twin is ALWAYS identical?
Mo/mo
