PSIO202 Exam 4 - Pregnancy and Development

Question 1

What are the three stages of gestation called? What is the timeline for these stages?

Answer 1

Germinal (first two weeks after fertilization), embryonic (weeks 3-8), and fetal (weeks 9-38+)

Question 2

What occurs during the germinal stage of gestation?

Answer 2

Zygote —-> morula (solid ball of cells)—-> blastocyst (hollow ball of cells with some differentiation)

After implantation, the blastocyst is called an embryo

Question 3

What occurs during the embryonic stage of gestation?

Answer 3

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

Question 4

What happens in the first week of development?

Answer 4

Implantation:
- on day 6-7 that blastocyst implants
- blastocyst has trophoblast and embryoblast cells

Question 5

What happens during the second week of development?

Answer 5

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

Question 6

What happens during the third week of development?

Answer 6

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

Question 7

What organ systems develop from the ectoderm?

Answer 7

Nervous and epidermis

Question 8

What organ systems develop from the mesoderm?

Answer 8

Cartilage, bone and connective tissues
Skeletal, cardiac, and smooth muscle tissue
Blood vessels and lymphatic vessels
Epithelium of the gonads

Question 9

What organ systems develop from the endoderm?

Answer 9

Epithelium of the digestive tract
Epithelium of the respiratory system
Epithelium of the thyroid, liver, and pancreas
Epithelium of the bladder

Question 10

During what month does the placenta form?
What does it develop from?

Answer 10

3rd month, from the embryonic chorion and uterine tissue

Question 11

What are the functions of the placenta?

Answer 11

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)

Question 12

What composes the umbilical cord?

Answer 12

2 umbilical arteries and 1 umbilical vein

Question 13

Fetal blood vessels contain —— blood and are surrounded by ——- blood.

Answer 13

Contain fetal, surrounded by maternal

Question 14

What is the main endocrine function of the placenta?

Answer 14

After 4 months, the placenta produces estrogen and progesterone

Question 15

What are the 4 things produced by the placenta?

Answer 15

HCG
relaxin
human chorionic somatomammotropin (hCS)
corticotropin-releasing hormone (CRH)

Question 16

What are the roles of hCG?

Answer 16

Maintain endometrium of the uterus during pregnancy
Prepare the mammary glands for lactation
Prepare the mothers body for birth

Question 17

What are the roles of relaxin?

Answer 17

Increase flexibility of pubic symphysis
Dilate uterine cervix during labor

Question 18

What are the roles of human chorionic somatomammotropin (hCS)?

Answer 18

Prepare mammary glands for lactation
Enhance growth by increasing protein synthesis
Decrease glucose use and increase fatty acid use for ATP production

Question 19

What are the roles of corticotropin-releasing hormone (CRH)?

Answer 19

Establishing the timing of birth
Increases secretion of cortisol (needed for maturation of fetal lungs and production of surfactant in fetal alveoli)

Question 20

From week —- to —-, the fetus grows from — inches to — inches.

Answer 20

Week 9 to 38
3 inches to 20 inches

Question 21

What are the 3 stages of birth?

Answer 21

Dilation, expulsion, and placental stage

Question 22

What indicates preeclampsia and eclampsia?

Answer 22

Preeclampsia: 140-160 systolic, 90-110 diastolic, proteinuria
Eclampsia: >160 systolic, >110 diastolic, proteinuria, and seizures

Question 23

Preeclampsia and eclampsia account for —% of all pregnancy induced hypertension cases.

Answer 23

5%

Question 24

What are the maternal and fetal mortality rates of severe preeclampsia and eclampsia?

Answer 24

Mother: 0-1.8%
Fetal: 5.6-11.8%

Question 25

What is the cause of preeclampsia and eclampsia?

Answer 25

Damage to the vascular component of the placenta, causes release of hormones that vasoconstrict

Question 26

What organ systems are damaged/involved in preeclampsia and eclampsia?

Answer 26

Kidney, cardiovascular, liver, blood cells, central nervous system, and placenta

Question 27

Why is there protein in the urine during preeclampsia and eclampsia?

Answer 27

Damage to the glomerular capillaries allows proteins to enter the filtrate