Human Embryology 1

Question 1

Process of an individual organism growing organically

Answer 1

Ontogenesis

Question 2

Gestational Period from fertilization to parturition of mature fetus

Answer 2

38 week (266 days)

Question 3

Three periods of gestation

Answer 3

1. Preembryonic period
2. Embryonic period [Week 3-8] (sensitive to congenital malformations)
3. Fetal period [Week 9 - birth]

Question 4

Gametes are _______ cells

Answer 4

Haploid

Question 5

Somatic cell are _______ cells

Answer 5

Diploid

Question 6

Mitochondria-filled area of the tail of the mature spermatozoon

Answer 6

Middle piece

Question 7

The removal of glycoprotein coat and seminal plasma proteins to allow sperm to fertilize an ovum

Answer 7

Capacitation of sperm

Question 8

The process by which the male and female gametes (sperm and ovum) unite to give rise to a zygote

Answer 8

Fertilization

Question 9

Ampullary region of the oviduct

Answer 9

Site of fertilization

Question 10

Three phases of fertilization

Answer 10

1. Penetration of corona radiata
2. Recognition and penetration of zona pellucida
3. Membrane fusion and entry

Question 11

After sperm binds to zona pellucida, induced by calcium ion influx

Answer 11

Acrosome reaction

Question 12

Ovum (22+X) + Sperm (22+X)

Answer 12

Female

Question 13

Ovum (22+X) + Sperm (22+Y)

Answer 13

Male

Question 14

24 hours after fertilization, the mammalian zygote (1 cell) begins cleavage - forming 2 blastomeres; then 4 blastomeres

Answer 14

Cleavage

Question 15

After 72 hours, blastomeres multiply forming

Answer 15

Morula

Question 16

Blastocyst formation occurs day

Answer 16

4-5

Question 17

Blastocyst is also called

Answer 17

Blastula

Question 18

Three parts of blastocyst

Answer 18

1. Inner cell mass (embryoblast)
2. Trophoblast (outer cell mass)
3. Blastocyst cavity (blastocoele)

Question 19

Develops into embryo proper

Answer 19

Inner cell mass

Question 20

Forms at the time 4-5 days after fertilization

Answer 20

Blastocyst

Question 21

The discovery of Human Embryonic Stem Cells accredited to

Answer 21

James Thomson

Question 22

The process by which the blastocyst is embedded into the endometrium of the uterus

Answer 22

Implantation

Question 23

Implantation occurs after fertilization on day

Answer 23

7-8
6th - 7th ~ 11th - 12th

Question 24

The process of implantation

Answer 24

Zona pellucida disappear —> polar trophoblast touch the endometrium —> secrete proteolytic enzyme —> binds to endometrium wall —> the area is sealed

Question 25

Implantation occurs in which phase of cyclic changes of the endometrium (menstrual cycle)

Answer 25

Secretory phase

Question 26

Trophoblast proliferates into two layers

Answer 26

1. Syncytiotrophoblast (has lacunae filled with maternal blood - filled with nutrition for fetus) 2. Cytotrophoblast

Question 27

Implantation occurs normally in

Answer 27

Posterior wall of fundus and body of uterus

Question 28

Implantation occurs abnormally in

Answer 28

1. Placenta praevia 2. Ectopic pregnancy (most often in oviduct)

Question 29

Cells of the endometrium become polyhedral and loaded with glycogen and lipid droplets

Answer 29

Decidua reaction

Question 30

The functional zone (functionalis) of the endometrium that performs the decidua reaction

Answer 30

Decidua

Question 31

Three layers of the Decidua

Answer 31

1. Decidua Basalis 2. Decidua Capsularis 3. Decidua Parietalis **key figure for examination**

Question 32

**At the beginning of the 2nd week, bilaminar germ disc is formed** having

Answer 32

1. Epiblast 2. Hypoblast

Question 33

Amnioblasts differentiate into

Answer 33

Amniotic epithelium to form the amnion

Question 34

Occurs during the third week of gestation, changes from bilaminar germ disc to trilaminar germ disc

Answer 34

Gastrulation

Question 35

The appearance of the primitive streak determines the

Answer 35

Cranial and caudal end of the germ disc

Question 36

Primitive node is at the _______ of the germ disc

Answer 36

Cranial end

Question 37

Cells of the primitive groove proliferate and migrate downwards to form two cell layers

Answer 37

1. Mesoderm 2. Endoderm

Question 38

Epiblast changes its name to ______ by the end of the third week during the formation of the trilaminar germ disc

Answer 38

Ectoderm

Question 39

At the cranial end of the primitive streak

Answer 39

Oropharyngeal membrane (having endoderm & ectoderm, but no mesoderm)

Question 40

At the caudal end of the primitive streak is the

Answer 40

Cloacal membrane (having endoderm and ectoderm, but no mesoderm)

Question 41

Cells of the primitive pit proliferate and grow in the cranial direction forming the: **important in the formation of the neural tube**

Answer 41

Notochord

Question 42

The embryonic period is also called the

Answer 42

Period of organogenesis

Question 43

Differentiation of ectoderm occurs between days _______ and results in the formation of the neural plate

Answer 43

18~19

Question 44

Anterior neuropore will be closed at the _____ day after fertilization

Answer 44

25th

Question 45

Posterior neuropore will be closed at the _____ day after fertilization

Answer 45

27th

Question 46

Premordium of the Central Nervous System (from the ectoderm)

Answer 46

Neural tube

Question 47

Anterior neuropore not closed

Answer 47

No brain

Question 48

Posterior neuropore is not closed

Answer 48

Spina bifida

Question 49

The ectoderm becomes the Peripheral Nervous System from the

Answer 49

Neural crest

Question 50

Differentiation of the mesoderm occurs on the

Answer 50

17th day

Question 51

Intermediate mesoderm forms

Answer 51

Most of the organs in the urinary and reproductive (genital) system

Question 52

Lateral mesoderm has

Answer 52

1. Intraembryonic coelum 2. Somatic (parietal) mesoderm 3. Splanchnic (visceral) mesoderm

Question 53

Lateral mesoderm also forms

Answer 53

Heart and blood vessels

Question 54

The epithelium of the digestive and respiratory system are derived from the

Answer 54

Endoderm

Question 55

At the caudal end, structure present called the

Answer 55

Allantois