14. Human Development

Question 1

ferilization usually occurs at this site

Answer 1

ampulla of the uterine tubes

Question 2

Approximately thirty hours after fertilisation, the fertilised oocyte (egg) splits into two cells of equal size; called

Answer 2

blastomeres

Question 3

the fertilised oocyte (egg) splits into two cells of equal size; called blastomeres. After three more divisions, there are ___ cells

Answer 3

16 cells called morula

Question 4

how many cells in morula

Answer 4

16 cells

Question 5

Within the first week, the cells of the morula reorganise to form a cavity, known as the

Answer 5

blastocyst cavity (blastocoel)

Question 6

Within the first week, the cells of the morula reorganise to form a cavity, known as the blastocyst cavity (blastocoel). From this point, the morula is known as

Answer 6

blastocyst

Question 7

two diff cell types in the blastocyst

Answer 7

Outer cell mass (trophoblast)

Inner cell mass (embryoblast)

Question 8

contacts with the endometrium of the uterus to facilitate implantation and the formation of the placenta.

Answer 8

Outer cell mass (trophoblast)

Question 9

responsible for the formation of the embryo itself.

Answer 9

Inner cell mass (embryoblast)

Question 10

During the ___ week, the trophoblast and embryoblast divide into increasingly specialised cell types.

Answer 10

second

Question 11

The trophoblast divides into the

Answer 11

syncytiotrophoblast and cytotrophoblast.

Question 12

embryoblast divides into the

Answer 12

epiblast and hypoblast, forming a two-layered structure; the bilaminar disk.

Question 13

The amniotic cavity forms within the

Answer 13

epiblast

Question 14

during implantation, _____ becomes continuous with the uterus

Answer 14

syncytiotrophoblast

Question 15

During implantation, what specific structures become continuous

Answer 15

maternal blood vessels (known as sinusoids) invade the spaces within the syncytiotrophoblast (known as lacunae)
-> uteroplacental circulation

Question 16

In placenta praevia, implantation of the embryo occurs in the

Answer 16

lower uterine segment (instead of in the normal position of the upper posterior uterine wall).

Question 17

gastrulation occurs ___ week of development

Answer 17

3rd week

Question 18

During this process, the two cell layers become three germ cell layers, and the bodily axes observed in the mature adult are created.

Answer 18

gastrulation

Question 19

Gastrulation is a process of cellular rearrangement which involves migration, invagination and differentiation of the

Answer 19

epiblast

Question 20

gastrulation is largely controlled and orchestrated by the

Answer 20

primitive streak

Question 21

is a groove in the midline of the epiblast which appears during the third week.

Answer 21

primitive streak

Question 22

this structure is at the cranial end of the primitive streak

Answer 22

primitive node

Question 23

within the primitive node lies this structure

Answer 23

primitive pit

Question 24

Cells of the epiblast layer break off and migrate toward the

Answer 24

primitive pit

Question 25

Cells of the epiblast layer break off and migrate toward the primitive pit. Here, they detach and penetrate through the epiblast layer to form three new germ cell layers:

Answer 25

endoderm mesoderm ectoderm

Question 26

formed by epiblast cells that migrate through the primitive pit and displace the hypoblast cells.

Answer 26

endoderm

Question 27

formed by epiblast cells that migrate through the primitive pit and lie between the epiblast layer and the newly created endoderm.

Answer 27

mesoderm

Question 28

formed by the epiblast cells that remain in position.

Answer 28

ectoderm

Question 29

3 phases of fertilization

Answer 29

1. sperm penetration of corona radiata 2. sperm binding and penetratio of zona pellucida -> acrosome rxn -> releases acrosin 3. fusion of sperm and oocyte cell membrane -> secondary oocyte completes meiosis II forming mature ovum and second polar body; male and female pronuclei fuse forming a zygote

Question 30

results of fertilization

Answer 30

1. formation of new individual 2. restoration of diploid number of chromosomes 3. determination of sex 4. initiation of cleavage

Question 31

series of mitotic divisions of zygote

Answer 31

cleavage

Question 32

blastomeres form morula by undergoing

Answer 32

compaction

Question 33

fertilization occurs after __ hours after ovulation

Answer 33

12-24 hours

Question 34

2 cell stage is __ afters after fertilization

Answer 34

30 hours

Question 35

morula is ___ days of age

Answer 35

30 days

Question 36

blastocyst is __ days of age

Answer 36

5 days

Question 37

implantation happens day __ after fetilization

Answer 37

7 days

Question 38

implantation usually happens at this part of the uterus

Answer 38

posterior superior wall

Question 39

at what layer of the endometrium do fertilization happens

Answer 39

secretory phase of the menstrual cycle

Question 40

the most common type of ectopic pregnancy

Answer 40

tubal pregnancy 95%

Question 41

most dependent part of entire peritoneal cavity when patient is in standing position

Answer 41

pouch of douglas

Question 42

frequently becomes the site for accumulation of blood (ruptured ectopic pregnancy ) or pus (ruptured appendicitis or gonococcal peritonitis)

Answer 42

Pouch of douglas

Question 43

needle passed into the pouch of douglas through the posterior fornix

Answer 43

culdocentesis

Question 44

structures penetrated by culdocentesis

Answer 44

1. mucous membrane - vagina 2. muscular coat- vagina 3. connective tissue coat- vagina 4. visceral layer of pelvic fascia 5. visceral layer of peritoneum