Intro to Embryo 8-24

Question 1

Embryonic Period

Answer 1

Fertilization to 8 weeks - initial development of all major structures and establishment of all organ systems

Question 2

Fetal Period

Answer 2

9th week (57 day) to 38th week - differentiation and growth of organs and tissues

Question 3

Teratology

Answer 3

Study of abnormal development (generic/environmental causes)

Question 4

LNMP

Answer 4

last normal menstrual period - 40 week pregnancy as opposed to 38 week pregnancy from fertilization to birth

Question 5

Gametogenesis

Answer 5

Formation of PMGs, occurs at week 7

Question 6

PMG

Answer 6

Primordial Germ cells - originate from endodermal cells of umbilical vesicle near origin of allantois as specific cells lining yolk sac. Migrate to gonads where they mature. Start as large cells recognizable 24 days after fertilization.

Question 7

PMG

Answer 7

2N

Question 8

Dorsal mesentary

Answer 8

Where germ cells migrate

Question 9

Genital Ridge

Answer 9

Will form ovaries or testies

Question 10

Indifferent Stage

Answer 10

Cannot differentiate between sexes

Question 11

Oogenesis

Answer 11

Occurs in month 3 - at prophase I it halts. Only about 500 are ovulated. Oogonia to oocyte - 2 million oocytes.

Question 12

Infundibulum

Answer 12

Like a funnel focused @ ovary.

Question 13

Fimbriae

Answer 13

Little fingers over ovary from infundibulum. Smooth muscle then moves egg through ampula (fertilization likely occurs here).

Question 14

Spermatogenesis

Answer 14

Spermatogonia to sperm

Question 15

Maximum number of oocytes

Answer 15

Month 5 - 7 million oocytes

Question 16

Month 9

Answer 16

All oocytes in meiosis I, birth, 600-800K oocytes

Question 17

Menarche

Answer 17

First occurrence of menstruation, 400K oocytes

Question 18

Oocyte wall

Answer 18

Immotile all are 23X, Corona radiata, Zona pellucida

Question 19

Sperm

Answer 19

Motile, 23Y

Question 20

2 hormones

Answer 20

FSH, LH (anterior pituitary) - prior to fertilization

Question 21

FSH

Answer 21

follicular stimulating hormone. Tells 10-15 of the oocytes to start meiosis II and I.

Question 22

LH

Answer 22

Leutinizing hormone - surge that causes oocyte to be spit out to be picked up by fimbriae

Question 23

Zona RXN

Answer 23

causes only 1 sperm to be able to break into the nucleus

Question 24

Monula

Answer 24

12-32 blastomeres. Important stage because of inner and outer cell mass.

Question 25

Capacitation

Answer 25

Occurs after ejaculation 7hrs. Surface proteins remove acrosome, allows acrosome to interact with corona radiata and ZP.

Question 26

Hyperactivation

Answer 26

Type of sperm motility, helps sperm penetrate ZP

Question 27

Acrosome reaction

Answer 27

Allows sperm to break ZP.

Question 28

Fertilization steps

Answer 28

Zona reaction, sperm and oocyte cell membranes break down and fuse. Oocyte completes meiosis and forms pronucleus. Haploid pronuclei fuse and form diploid zygote — initiates cleavage. 1. Coronal cells 2. Acrosomal reaction 3. Fusion

Question 29

Blastomeres

Answer 29

Early embryonic cells from zygote that start to form within 30 hours of fertilization. Zona pellucida confines cells.

Question 30

Compaction

Answer 30

Begins at 8 cells

Question 31

Ectopic Pregnancy

Answer 31

Implantation occurs in abnormal position - usually in uterine tubes.

Question 32

Lithopedium

Answer 32

Embryo in abdomen, calcifies

Question 33

Cervical implantation

Answer 33

Results in heavy bleeding.

Question 34

Blastocyst

Answer 34

no more zona pellucida. Fluid enters blastocystic cavity and separates blastomeres. Trophoblast and Embryoblast

Question 35

Trophoblast

Answer 35

Forms extra embryonic structures (placenta). Troph=nutrients.

Question 36

Posterior Wall

Answer 36

Best place for implantation. Tropoblast cells attach to endometrium. Once this occurs, tropoblast differentiates into cytotrophoblast and syncytiotrophoblast (day 7).

Question 37

Cytotrophoblast

Answer 37

Line blastocystic cavity

Question 38

Syncytiotrophoblast

Answer 38

“Finger” type cells that extend and attach to endometrium.

Question 39

Hypoblast

Answer 39

Small cuboidal cells that form from embryoblast. These will form the primary endoderm.