Embryology intro

Question 1

diff b/w baby and mom development duration

Answer 1

38 weeks for baby, 40 for mom (40 weeks from LMP)

Question 2

embryonic period

Answer 2

weeks 3-8, embryo w/ organogenesis

Question 3

weeks 1-2

Answer 3

zygote-morula-blastocyst; fertilization and implantation

Question 4

fetal period

Answer 4

weeks 9-38, fetus- growth and maturation

Question 5

birth defect

Answer 5

congenital abnormality present at birth

Question 6

malformation

Answer 6

structural abnormality secondary to intrinsic process like genetic abnormality

Question 7

deformation

Answer 7

abnormality secondary to extrinsic process

Question 8

sequence

Answer 8

multiple abnormalities developing in order

Question 9

syndrome

Answer 9

multiple abnormalities in no known sequence

Question 10

abnormal development in weeks 1-2

Answer 10

not susceptible to teratogens, secondary to inherited genetics

Question 11

abnormal development in embryonic period

Answer 11

most vulnerable time! susceptible to all types, major anomalies when development is disrupted while structure is only a few cells

Question 12

abnormal development in fetal period

Answer 12

susceptible to all types, minor anomalies b/c structures are almost fully formed

Question 13

common “directions” of development

Answer 13

cranial to caudal, proximal to distal

Question 14

fns performed by placenta

Answer 14

fetal lungs, kidneys, GI tract

Question 15

fetus interaction (body processes) w/ amniotic fluid

Answer 15

breathes the fluid, urinates into fluid, does NOT defecate in utero

Question 16

process during week 1 in order

Answer 16

fertilization- zygote division- morula- early blastocyst- late blastocyst- implantation in uterus

Question 17

differentiate 2 components of late blastocyst

Answer 17

inner cell mass- becomes fetus

trophoblast- becomes placenta and fetal membranes

Question 18

week 2 processes

Answer 18

inner cell mass into epiblast (embryo) and hypoblast (disappears), amniotic cavity appears, primitive streak forms

Question 19

primitive streak

Answer 19

dorsal, caudal midline in epiblast - precursor to 3 germ layers

Question 20

dorsal view

Answer 20

“birds eye”- cranial up at the top and caudal at the bottom

Question 21

transverse view

Answer 21

cross section- top is posterior/dorsal, bottom is anterior/ventral

Question 22

week 3 development- 3 main processes

Answer 22

gastrulation (trilaminar embryo w/ 3 layers), somite formation, neurulation

Question 23

gastrulation

Answer 23

epiblast becomes ectoderm, 2 new layers form under epiblast at primitive streak: mesoderm and endoderm

Question 24

ectoderm

Answer 24

epidermis, teeth, nervous system

Question 25

mesoderm

Answer 25

muscle, bone, connective tissue, vessels and blood, dermis

Question 26

endoderm

Answer 26

epithelium of GI and respiratory tracts

Question 27

mesenchyme

Answer 27

aggregates of undifferentiated cells, mostly from mesoderm

Question 28

somites

Answer 28

horizontal body segments, form during week 3 from mesoderm

Question 29

3 somite divisions

Answer 29

dermatome- skin, myotome- muscle, sclerotome- bone

Question 30

3D embryo structure beginning of week 4

Answer 30

flat!!! during week 4, folding begins in 2 directions

Question 31

longitudinal folding, visualize longitudinal section

Answer 31

cranial and caudal ends fold ventrally- heart moved from cranial to new thorax and begins to beat

Question 32

transverse folding, visualize cross-section view

Answer 32

lateral sides fold ventrally and fuse at the ventral midline

creates GI tract and body cavity precursor (coelom)

new germ layers begin to differentiate

Question 33

major events of week 4

Answer 33

beginning of transverse and longitudinal folding, germ layer differentiation