PSIO202 Exam 4 - Pregnancy and Development Flashcards
What are the three stages of gestation called? What is the timeline for these stages?
Germinal (first two weeks after fertilization), embryonic (weeks 3-8), and fetal (weeks 9-38+)
What occurs during the germinal stage of gestation?
Zygote —-> morula (solid ball of cells)—-> blastocyst (hollow ball of cells with some differentiation)
After implantation, the blastocyst is called an embryo
What occurs during the embryonic stage of gestation?
Embryo develops the 3 primary tissue layers and the beginning of every organ/organ system
Embryo becomes a fetus at the end of the 8th week
What happens in the first week of development?
Implantation:
- on day 6-7 that blastocyst implants
- blastocyst has trophoblast and embryoblast cells
What happens during the second week of development?
Development of trophoblast, amnion, and bilaminar embryonic disc
- merging of walls forms the syncytiotrophoblast and cytotrophoblast layers
- amnion and amniotic cavity forms in what was the embryblast cell cluster
- layer of epiblast and hypoblast inside the blastocyst (bilaminar embryonic disc)
Development of the yolk sac, syncytiotrophoblast, and lacunae
- blastocyst is completely burrowed
- hypoblast spreads throughout the entire blastocyst and forms the yolk sac
- lacunae start forming within the syncytiotrophoblast layer
Development of the chorion and lacunar network
- chorion: extraembryonic mesoderm, syncytiotrophoblast, and cytotrophoblast layers
What happens during the third week of development?
Connecting stalk and villi
- chorionic villi become part of the placenta later
- connecting stalk forms from the extraembryonic mesoderm
Gastrulation and three germ layers
-ectoderm folds and forms a trilaminar embryonic disc: ectoderm, mesoderm, and endoderm
Intervillous spaces and capillaries in the chorionic villi
- capillaries in the chorionic villi develop more
- intervillous spaces develop between the chorionic villi
Embryo, amniotic cavity, yolk sac, and vascular supply
- formation of the umbilical arteries and vein in the connecting stalk
- by day 19 the heart forms, and by the end of the 3rd week the heart is moving blood through the capillaries
What organ systems develop from the ectoderm?
Nervous and epidermis
What organ systems develop from the mesoderm?
Cartilage, bone and connective tissues
Skeletal, cardiac, and smooth muscle tissue
Blood vessels and lymphatic vessels
Epithelium of the gonads
What organ systems develop from the endoderm?
Epithelium of the digestive tract
Epithelium of the respiratory system
Epithelium of the thyroid, liver, and pancreas
Epithelium of the bladder
During what month does the placenta form?
What does it develop from?
3rd month, from the embryonic chorion and uterine tissue
What are the functions of the placenta?
Site of nutrient, gas, and waste exchange
Secretes hormones to maintain pregnancy (after corpus luteum degenerates)
Barrier to microorganisms (except some viruses, and not a barrier to drugs like alcohol)
What composes the umbilical cord?
2 umbilical arteries and 1 umbilical vein
Fetal blood vessels contain —— blood and are surrounded by ——- blood.
Contain fetal, surrounded by maternal
What is the main endocrine function of the placenta?
After 4 months, the placenta produces estrogen and progesterone
What are the 4 things produced by the placenta?
HCG
relaxin
human chorionic somatomammotropin (hCS)
corticotropin-releasing hormone (CRH)
What are the roles of hCG?
Maintain endometrium of the uterus during pregnancy
Prepare the mammary glands for lactation
Prepare the mothers body for birth
What are the roles of relaxin?
Increase flexibility of pubic symphysis
Dilate uterine cervix during labor
What are the roles of human chorionic somatomammotropin (hCS)?
Prepare mammary glands for lactation
Enhance growth by increasing protein synthesis
Decrease glucose use and increase fatty acid use for ATP production
What are the roles of corticotropin-releasing hormone (CRH)?
Establishing the timing of birth
Increases secretion of cortisol (needed for maturation of fetal lungs and production of surfactant in fetal alveoli)
From week —- to —-, the fetus grows from — inches to — inches.
Week 9 to 38
3 inches to 20 inches
What are the 3 stages of birth?
Dilation, expulsion, and placental stage
What indicates preeclampsia and eclampsia?
Preeclampsia: 140-160 systolic, 90-110 diastolic, proteinuria
Eclampsia: >160 systolic, >110 diastolic, proteinuria, and seizures
Preeclampsia and eclampsia account for —% of all pregnancy induced hypertension cases.
5%
What are the maternal and fetal mortality rates of severe preeclampsia and eclampsia?
Mother: 0-1.8%
Fetal: 5.6-11.8%
