Intro to Embryo

Question 1

40 weeks of pregnancy is measured from the _____

Answer 1

LNMP (last normal menstrual period); 280 days

Question 2

38 weeks of pregnancy is measured from ______

Answer 2

fertilization (266 days)

Question 3

the embryonic period spans from ____ to _____ and is ____ days

Answer 3

fertilization; 8 weeks; 56

Question 4

the fetal period spans from the ____ to _____

Answer 4

9th week or 57th day; term or 38th week

Question 5

initial development of all major structures and establishment of all organ systems

Answer 5

embryonic period

Question 6

differentiation and growth of organs and tissues

Answer 6

fetal period

Question 7

the study of abnormal development (genetic/environmental causes)

Answer 7

teratology

Question 8

stages of mitosis

Answer 8

preprophase, prophase, metaphase, anaphase, telophase, cytokinesis

Question 9

mitosis results in ___ ; 2 cells of ____ each

Answer 9

cell duplication; 2N

Question 10

the process of the formation and development of male and female primordial germ cells (PGCs) into their specialized generative cells–gametes

Answer 10

gametogenesis

Question 11

haploid numbers of chromosomes (23 chromosomes) is represented by ___

Answer 11

N

Question 12

number of copies of chromosomes present in a cell nucleus

Answer 12

ploidy

Question 13

number of copies of each unique double stranded DNA molecule is represented by ___

Answer 13

N

Question 14

stages of meiosis I

Answer 14

preprophase, prophase, metaphase, anaphase, telophase, cytokinesis

Question 15

stages of meiosis II

Answer 15

prophase, metaphase, anaphase, telophase, cytokinesis

Question 16

primordial sex cells (germ cells) originate as specific cells lining the ____ or _____; they originate as large spherical cells first recognizable 24 days after fertilization

Answer 16

yolk sac; umbilical vesicle

Question 17

PGCs are ___ and originate from the ____ of the umbilical vesicle near the origin of the allantois

Answer 17

diploid (2N); endodermal cells

Question 18

PGCs migrate to occupy ____ and mature into ____

Answer 18

gonads; gametes (mature sex cells: spermatozoa & oocyte)

Question 19

PGCs originate in the lining of the ____ and migrate along the ___ of the hindgut to the _____ during the 5th week of embryonic development

Answer 19

yolk sac; dorsal mesentery; gonadal ridge

Question 20

during the 6th week the PGCs enter the underlying ____ and are incorporated into the _____; at this time the gonads of the 2 sexes are identical in appearance and are thus _____

Answer 20

mesenchyme; gonadal cords; indifferent gonads

Question 21

process that reduces chromosomal number by 1/2; diploid to haploid 2N to N

Answer 21

gametogenesis

Question 22

spermatogonia to sperm (begins at ____)

Answer 22

spermatogenesis; begins at puberty

Question 23

oogonia to oocyte (begins before birth, halts, and continues at puberty)

Answer 23

oogenesis

Question 24

ovulation: beginning at puberty, cyclic ____ released from the _____

Answer 24

FSH (follicle-stimulating hormone) + LH (luteinizing); anterior pituitary gland

Question 25

FSH triggers ____ and LH surge triggers _____

Answer 25

follicular growth; ovulation

Question 26

the mature oocyte is released from the ____ during ovulation

Answer 26

ovary

Question 27

____ of the ____ is the normal site for fertilization

Answer 27

ampulla; uterine tube

Question 28

begins after ejaculation, takes about 7 hours and is initiated by substances secreted in the uterus and uterine tubes

Answer 28

capacitation

Question 29

capacitation is required to mature the sperm allowing removal of the ____ and _____ from the surface of the sperm ____ to allow the ____ to occur

Answer 29

glycoprotein coat; seminal proteins; acrosome; acrosomal reaction

Question 30

_____ follows capacitation-- increasing the activity of the sperm

Answer 30

hyperactivation

Question 31

occurs when the capacitated sperm acrosome binds to the zona pellucida (ZP3 glycoprotein)

Answer 31

acrosomal reaction

Question 32

during the acrosomal reaction, the acrosome begins to perforate in the presence of several enzymes and substances, breaking down the membranes producing aperatures; several enzymes are released, including ____ and ____ to facilitate fertilization

Answer 32

hyaluronidase; acrosin

Question 33

about 30 hours after fertilization, the zygote undergoes cleavage (mitosis) to make early embryonic cells called _____

Answer 33

blastomeres

Question 34

cell divisions result in successively smaller blastomeres that remain confined within the space available in the _____; this process is called ____

Answer 34

zona pellucida; compaction

Question 35

compaction begins at about ____ stage

Answer 35

8 cell

Question 36

3-4 days following fertilization, as the embryo is entering the uterus, the blastomere is in the ____ and is renamed the _____

Answer 36

12-32 cell stage; morula

Question 37

during the morula stage, the blastmeres start to organize into _____

Answer 37

an inner cell mass and an outer cell mass

Question 38

shortly after entering the uterus (days 4-5), the morula develops a fluid-filled cavity and is called a ______

Answer 38

blastocyst

Question 39

upon creation of the blastocyst, the _____ degenerates

Answer 39

zona pellucida

Question 40

blastocystic cavity splits blastomeres into two groups:

Answer 40

embryoblast and trophoblast

Question 41

the embryoblast is the _____ and gives rise to the _____

Answer 41

inner cell mass; embryo

Question 42

the trophoblast is _____ and becomes _____; also has ____ purpose

Answer 42

outer cell mass; extraembryonic structures (embryonic contribution to the placenta); nutritional

Question 43

On day ___, the trophoblast cells attach to the _____

Answer 43

6; endometrium(lining of uterus), on either the posterior (ideal) or anterior wall of the body of the uterus

Question 44

upon attachment, during day ___, the trophoblast differentiates into two distinct regions:

Answer 44

7; cytotrophoblast and syncytiotrophoblast

Question 45

the syncytiotrophoblast is composed of cells that are ______

Answer 45

embedded in the endometrium

Question 46

the cytotrophoblast is composed of cells that are _____

Answer 46

not embedded in the endometrium; just surrounding the developing embryo

Question 47

the cytotrophoblast gives rise to _____

Answer 47

extraembryonic structures

Question 48

blastocyst implants outside normal uterine locations

Answer 48

ectopic pregnancy

Question 49

common ectopic locations:

Answer 49

- within the uterine tubes (most common, 95-98%) - within the abdomen (ex: surface of the ovary, rectouterine pouch, mesentery) - abnormal site within the uterus (internal os, cervix)

Question 50

small cuboidal cells formed from the embryoblast

Answer 50

hypoblast

Question 51

hypoblast occurs during day ___, and will become the _____

Answer 51

7; primary endoderm

Question 52

the hypoblast sits ____ to the embryoblast

Answer 52

inferior

Question 53

3 phases of fertilization

Answer 53

1. coronal cells 2. acrosomal reaction 3. plasma membranes fuse, meiosis II resumes, and metabolism of oocyte increases

Question 54

results of fertilization

Answer 54

- haploid pronuclei fuse, forming diploid zygote - restoration of diploid number of chromosomes - determination of genetic sex - initiation of cleavage

Question 55

process of oogenesis

Answer 55

- oogenesis begins before birth - baby is born, oogenesis is halted during prophase I - at puberty, oocytes finish meiosis I - right before egg is ovulated, oogenesis is halted again at metaphase II - when egg is fertilized, it finishes meiosis II in the fallopian tube