Lec 1 fert and embryology

Question 1

Describe the anatomy of the human ovum

Answer 1

blue space is perivitelline space

Haploid 23X

Question 2

Describe the anatomy of the human sperm

Answer 2

Acrosome contains enzymes

Nucleus DNA 23X or 23Y

Neck is joining piece

Middle piece contains mito

Question 3

What events happen in week 1

Answer 3

• Fertilization
• cleavage
• formation blastocyst
• formation embryoblast
• implantation

Question 4

Where does fertilization occur?

Answer 4

Ampulla

Question 5

what must happen for fertilization to occur?

Answer 5

Capacitation- glycoprotein coat and seminal plasmsa proteins removed from plasma membrane of sperm (acrosome reaction release enzymes)

Question 6

After capacitation what happens?

Answer 6

passage of sperm through corona radiata with the release of Hyaluronidase

Question 7

What allows the sperm to pass through corona radiata?

Answer 7

Hyaluronidase

Question 8

After passage through corona radiata what happens?

Answer 8

penetration of zona pellucida- via release of

• esterases
• acrosin
• neuraminidase

Question 9

After penetration of the zona pellucida?

Answer 9

Zona Reaction (when one sperm enters zona pellucida (zona reaction) causes mesh to be rigid

blocking polyspermy (Granules?)

Question 10

After the zona reaction?

Answer 10

• Fusion of plasma membranes of oocyte and sperm
• Head and tail of sperm enter oocyte cytoplasm

(Sperm mitochondria do not enter)

Question 11

what happens once sperm enters oocyte cytoplasm?

Answer 11

• completion of second meiotic division
• formation of male pronucleus
• fusion of male and female pronuclei= zygote

Question 12

What are the results of fertilization?

Answer 12

Question 13

approximately how long does fertilization take?

Answer 13

7 hrs

Question 14

when does cleavage occur?

Answer 14

30 hr after fertilization

Question 15

what happens during the beginning of cell cleavage?

Answer 15

• Once we have two cells the cells are called blastomeres
• the cells increase in number but decrease in size
• embryo size stays the same
• form a morula

cadherins help this

Question 16

When does a morula form?

Answer 16

Around day 3

Question 17

From morula to what?

Answer 17

Blastocyst (Day 5)

fluid enters and creates cavity

Question 18

how many cells in a morula?

Answer 18

12-32 cells

Question 19

Implantation happens when?

Answer 19

around day 6

Question 20

What happens during day 5-7?

Answer 20

Early blastocyst to late blastocyst

• degenerating of zona pellucida

by day 7 it is gone (hatching of embryo)

Question 21

What does the trophoblast form?

the inner cell mass?

Answer 21

Placenta

embryo

Question 22

Blastocyst pic

Answer 22

Question 23

after one week how many layers in the embryo?

Answer 23

one layer

the inner cell mass

Question 24

Assisted reproductive technologies

Answer 24

• in vitro fertilization and embryo transfer
• cryopreservation of embryos
• intracytoplasmic sperm injection

(low sperm inject sperm into egg)

Question 25

in vitro fertilization and embryo transfer overview

Answer 25

Question 26

embryonic stem cells

Answer 26

from inner cell mass (patients dont know they are pregnant at this stage so get from cryo) pluripotent Somatic nuclear transfer

Question 27

Trophoblast gives rise to what?

Answer 27

* Cytotrophoblast * syncytiotrophoblast

Question 28

Cytotrophoblast is where and what does it do?

Answer 28

stem cell layer mitotically active

Question 29

Syncytiotrophoblast is where and what does it do?

Answer 29

* Multinucleated. * releases proteolytic enzymes responsible for implantation * releases chorionic gonadotropin hCG (initial signal of pregnancy)

Question 30

What happens in the first 10 days of implantation

Answer 30

immunosuppressant needs to be present

Question 31

What is a hydatidiform mole?

Answer 31

abnormal trophoblastic proliferation; excessive amounts of hCG produced 2 types Complete (Mole 1) Partial (Mole 2)

Question 32

Complete mole vs partial mole

Answer 32

C-fert of an empty oocyte, followed by duplication of the sperm. or from fert of an empty oocyte by two sperm P-fert of a normal oocyte by two sperm (no polyspermy block) (paternal fault)

Question 33

clinical features of a hydatidiform mole

Answer 33

* vaginal bleeding * pelvic pressure or pain * enlarged uterus * hyperemesis gravidarum (morning sickness) due to high hCG

Question 34

What can form from a nonremoved hydatidiform mole?

Answer 34

Choriocarcinomas (3-5 percent) -malignant tumor which develops from mole spread to liver lung vagina intestine bone and brain.

Question 35

Week 2 what structures are formed? what do they arise from?

Answer 35

* Epiblast * Hypoblast Inner cell mass

Question 36

What does Epiblast create?

Answer 36

* Ectoderm * amnion * amniotic cavity

Question 37

What does Hypoblast create?

Answer 37

Endoderm

Question 38

What is only present in week 2?

Answer 38

hypoblast replaced in wk 3

Question 39

Hypoblast to endoderm then to what?

Answer 39

Prechordal plate primary and secondary yolk sac (umbilical vessel) extraembryonic mesoderm

Question 40

Extraembryonic Coelom vs somatic mesoderm vs splanchnic

Answer 40

Question 41

Extraembryonic somatic mesoderm gives rise to what?

Answer 41

connecting stalk chorion

Question 42

extraembryonic splachnic mesoderm forms what?

Answer 42

Primitive blood

Question 43

abnormal implantation

Answer 43

tubal pregnancy placenta prev

Question 45

quick explanation of gastrulation

Answer 45

primitive streak in caudal end invaginates as cells grow into eachother. they then get new signals and migrate to the hypoblast where they replace the hypoblast cells with true endoderm. Signals also tell cells in the middle to then change into the true mesoderm. we now have 3 layers

Question 46

What gives rise to the diaphragm? heart?

Answer 46

septum transversum cardiogenic area

Question 47

what is prechordal plate and cloacal membrane made of what do they become?

Answer 47

made of ectoderm and mesoderm prechordal plate becomes mouth cloacal membrane to urinary repro

Question 48

sacroccoccygeal teratoma cause?

Answer 48

primitive streak from epiblast persisted and caused this

Question 49

Notochord germ layer type?

Answer 49

mesoderm

Question 50

Most important role of notochord?

Answer 50

induce the formation of neural plate and central nervous system (release sonic hedge hog)

Question 51

chordomas

Answer 51

from the notochord slow growing aggressive neoplasm of bone

Question 52

Mesoderm 3 layers with a notochord. what are the three types of mesoderm?

Answer 52

paraxial intermediate lateral plate

Question 53

Paraxial mesoderm creates what?

Answer 53

somites