Anatomy Block 2: Fertilization To Trilaminar Germ Disc

Front 1

permanent teeth replacing milk teeth and myelination of nerve fibers are processes that occur before or after birth?

Back 1

development after birth

Front 2

The pre-embryonic period is from weeks _________.

Back 2

weeks 1 to 2

Front 3

The fetal period is from weeks ___________.

Back 3

week 9 until birth

Front 4

Organogenesis occurs in what period?

Back 4

embryonic period (weeks 3-8)

Front 5

vulnerability to harmful environmental influences is highest during what period?

Back 5

embryonic period (weeks 3-8)

Front 6

Gametes contain ____ autosomes and ____ sex chromosomes.

Back 6

22 autosomes

1 sex chromosome

Front 7

What is the haploid (1n) number of chromosomes?

Back 7

23

Front 8

Oocytes contain a ______ chromosome and spermatozoa contain a _________ chromosome.

Back 8

-oocytes: always X chromsome
-spermatozoa: may contain X OR Y

Front 9

How are gametes created?

Back 9

a germ cell undergoes meiosis, where one DNA replication is followed by two cell divisions creating a total of 4 haploid gametes

Front 10

Each primary oocyte gives rise to how many functional oocytes?

Back 10

Only one. The other 3 haploid cells become nonfunctional polar bodies

Front 11

A numerical chromosomal abnormality (having 22 or 24 chromosomes instead of the normal 23) occurs by what mechanism?

Back 11

nondisjunction of chromosomes during meiosis

Front 12

In ovulation, a ______________ is swept into the uterine tube by ___________.

Back 12

-secondary oocyte
-fimbriae

Front 13

An oocyte and sperm combine to form a ___________. This occurs in the ___________________.

Back 13

-zygote (now considered diploid/2n)
-occurs in AMPULLA of the uterine tube

Front 14

During the initial cleavage of the zygote, the dividing cells are called ______________ and progressively become ______________ as they divide because little growth occurs between each cell division.

Back 14

-blastomeres
-smaller

Front 15

Three days after fertilization, at the 16-cell stage, the conceptus is called a ....

Back 15

morula or mulberry

Front 16

The inner cell mass of the morula is called the ______________ and eventually forms the ______________.

Back 16

-embryoblast
-embryo proper

Front 17

The outer cell mass of the morula is called the ______________ and eventually forms the ______________.

Back 17

-trophoblast
-placenta

Front 18

What forms when fluid penetrates between blastomeres to form a fluid-filled cavity?

Back 18

a blastocyst/blastocele/blastocyst cavity

Front 19

When does the blastocyst implant itself on the endometrium of the uterus?

Back 19

5 1/2 to 6 days following fertilization

Front 20

What results from the fertilization of two oocytes by two sperm?

Back 20

fraternal/dizygotic twins...accounts for 2/3 of all twins

Front 21

What kind of twins develop from a single fertilized ovum?

Back 21

monozygotic/identical twins

Front 22

The majority of monozygotic twins split at what stage of gestation?

Back 22

the early blastocyst stage

Front 23

Only _____% of conceived twins are both born alive, and those that are born alive have a higher mortality rate.

Back 23

29%

Front 24

Conjoined (Siamese) twins may be joined at the thorax ( ____________ ), sacral region ( _____________ ), or head ( __________________ ).

Back 24

-thorax: thoracopagus
-sacral: pygopagus
-head: craniopagus

Front 25

Infertility is a problem for ___________ of couples.

Back 25

15% to 30%

Front 26

Infertility in females may be due to occluded uterine tubes (often resulting from ____________________).

Back 26

pelvic inflammatory disease

Front 27

What 3 methods are used to treat infertility?

Back 27

1. in vitro fertilization
2. gamete intrafallopian transfer
3. intracytoplasmic sperm injection

Front 28

If an abnormal gamete with a numerical chromosomal abnormality participates in fertilization, an embryo with one too few ( ____________ ) or one too many ( _____________ ) chromosomes results.

Back 28

-monosomy

-trisomy

Front 29

An _______________ is when the embryo implants at any abnormal site.

Back 29

ectopic pregnancy

Front 30

pana e ko jaki  

Back 30

to pooh

Front 31

What are the 3 places an ectopic pregnancy may occur?

Back 31

1. uterine tube (most common)
2. retrouterine pouch
3. ovary

Front 32

If the conceptus implants close to the internal os of the uterus, the growing placenta will later bridge the opening, causing hemorrhaging late in pregnancy. This is called...

Back 32

placenta previa

Front 33

In the 2nd week of development, the embryoblast differentiates into ______________________.

Back 33

the bilaminar germ disc

Front 34

The amniotic cavity of the bilaminar germ disc forms within the ________________.

Back 34

epiblast layer

Front 35

In the bilaminar germ disc, the cells adjacent to the cytotrophoblast are called...

Back 35

amnioblasts

Front 36

In the bilaminar germ disc, the layer adjacent to the primitive yolk sac is called the...

Back 36

hypoblast layer

Front 37

During the third week of development, the _____________________ forms.

Back 37

trilaminar germ disc

Front 38

The trilaminar germ disc consists of 3 germ layers called the...

Back 38

1. endoderm
2. mesoderm
3. ectoderm

Front 39

The trilaminar germ disc forms after the bilaminar germ disc undergoes ______________, which is the invagination of the ________ layer.

Back 39

gastrulation

epiblast

Front 40

Gastrulation begins with the appearance of the____________ and _____________ on the surface of the epiblast.

Back 40

primitive streak and primitive pit

Front 41

During gastrulation, _________ cells migrate into the primitive streak and primitive pit and detach (invagination).

Back 41

epiblast

Front 42

Some invaginating epiblast cells displace the hypoblast to form the _______________ while others stop between the epiblast and the endoderm to form the ___________. The cells in the remaining epiblast are now called the ___________.

Back 42

-endoderm

-mesoderm

-ectoderm

Front 43

Invaginating cells that migrate cephalically in the midline form the ___________ and ___________.

Back 43

-notochord

-prechordal mesoderm

Front 44

The prechordal mesoderm lies between the tip of the notochord and the ______________________.

Back 44

bucco-pharyngeal/oropharyngeal membrane

Front 45

The bucco-pharyngeal/oropharyngeal membrane is the...

Back 45

future site of the oral cavity

Front 46

Body axes/sides are established during gastrulation due to _________________.

Back 46

secretions that are present on only one side of the midline

Front 47

Head development results from molecular signals coming from the ____________.

Back 47

anterior visceral endoderm

Front 48

The primitive streak forms caudally under control of genes in the ____________.

Back 48

primitive node

Front 49

Holoprosencephaly is a gastrulation abnormality in which the __________________ are deficient. This can be caused by ___________.

Back 49

-midline craniofacial structures
-caused by high doses of alcohol

Front 50

Sirenomelia (caudal dysgenesis) is a gastrulation abnormality where there is ________________________.

Back 50

-insufficient mesoderm in the caudal part of the embryo, causing fused or deficient lower limbs

Front 51

A sacrococcygeal teratoma is a tumor formed from the ________________.

Back 51

remnants of the primitive streak (or from primordial germ cells)

Front 52

The most common tumor in newborns is...

Back 52

sacrococcygeal teratoma

Front 53

transposition of organs occurs in the thorax and abdomen is called

Back 53

situs inversus