Gastrulation and Fertilization

Question 1

Anatomy of the Human Ovum

Answer 1

Corona Radiata
Zona Pellucida 
Nucleus
Perivitelline Space-chemical reactions occur in this space
Plasma Membrane

Question 2

Anatomy of the Human Sperm

Answer 2

Head: Acrosome (contains enzymes important for fertilization), and Nucleus
Neck
Tail: (flagella) Middle piece which contains the mitochondria
Principle Piece
End Piece

Question 3

What day does ovulation occur

Answer 3

Day 14 same day as the start of the Fertilization or Ovulatory Calendar

Question 4

Zona Pellucida

Answer 4

protioglycan meshwork

Question 5

Where does fertilization occur

Answer 5

Occurs in the Ampula (distal 2/3) of the Ovarian Tube

Question 6

Capacitation

Answer 6

remove the cap or the glycoprotein coat of the acrosome.

occurs in the uterus

Question 7

Step 1 of fertilization

Answer 7

Capatication
passage of sperm through the corona radiata by releasing hyaluronidase via the acrosome
Movement of the sperm helps as well
tubomucosal proteins

Question 8

Step 2 of fertilization

Answer 8

Penetration of the zona pellucida
Esterases, acrosin, neuraminidasse released from the acrosome
zona reaction

Question 9

Zona Reaction

Answer 9

once one sperm gets through this reaction freezes the meshwork and blocks the polysperm

Question 10

Step 3

Answer 10

Fusion of the sperm with the plasma membrane

sperm enters the oocyte cytoplasm

Question 11

Step 4

Answer 11

Completion of the second Meiotic division
formation of male pronucleus
and fusion between the mae and female pronuclei

Question 12

Blastomeres

Answer 12

Beginning of clevage and the cells that are made, 2, 4, 8

Question 13

Clevage

Answer 13

begins 30 hours after fertilization
increase the cell number but not size,

day 3 generate the morula
and day 4 the morula enters the uterus

Question 14

Blastocyst

Answer 14

day 5-7
cells go to one side and create the embryoblast (inner cell mass)

Blastocyst cavity (uterian fluid)
Tropoblast
degenerating zona pellucida

Question 15

Tropoblast

Answer 15

is the stem cells for the placenta

release early pregnancy factor

give rise to Cytotrophoblast

Question 16

When does implantation occur

Answer 16

day 6 as a blastocyst

Question 17

Assisted Reproductive Technologies

Answer 17

in vitro Fertilization and embryo transfer

Cyropreservation of Embryos

Intracytoplasmic sperm Injection

Question 18

Cytotrophoblast

Answer 18

stem cells of the placenta and are the mitotically active cells
give rise to the Syncytiotrophoblast

Question 19

Syncytiotrophoblast

Answer 19

multinuclear and no cell walls
secrete proteolytic enzymes, chorionic gonadotropin (hCG)
responsible for implantation into endometrium of the uterus
and initial pregnancy signal. (day 6)

Question 20

Hydatidiform Mole

Answer 20

abnormal trophoblastic proliferation and excessive amounts of hCG

Complete- fertilization of an empty oocyte and duplication of the sperm, or from fertilization of an empty oocyte by two sperm

Partial- fertilization of a normal oocyte by two sperm

vaginal bleeding-prune juice
pelvic pressure and pain
enlarged uterus
hyperemesis gravidarum (morning sickness)

lead to Choriocarcinomas

Question 21

Week 2

Answer 21

two cell layer and a bilaminar disc
innercell mass gives rise to Epiblast-Ectoderm, aminon, and aminon cavity

and give rise to Hypoblast works as placeholder until week 3

Question 22

Hypoblast

Answer 22

gives rise to endoderm (extra embryonic)
Prechrdal plate: clonar cells which becomes future mouth
primary and secondary yolk sac (umbilical vesicle)
Extraembryonic mesoderm

Question 23

Primary yolk sac and secondary yolk sac

Answer 23

created by the lining of the trophoblast by the hypoblast that will create the primary yolk sac

the secondary yolk sac is created by the pinching of the primary yolk sac to make two sacs

the primary yolk sac will then degenerate

Question 24

Extaembryonic Coelom

Answer 24

Hollow cavity outside of the embryo

Question 25

Extraembryonic somatic mesoderm

Answer 25

Lining the trophoblast covering the amnion Connecting stalk: precursor to umbilical cord and forms at embryonic pole Chorion: layer of placenta

Question 26

Extraembryonic Splanchnic Mesoderm

Answer 26

Lining of the yolk sac (umbilical vesicle) Primitive blood: forms in wall of yolk sac

Question 27

Ectopic pregnancies

Answer 27

Abnormal implanting Tubual pregnancy occurs in the Uterian Tube Number one way mom bleeds to death in pregnancy

Question 28

Placenta Previa

Answer 28

Implantation is very close to internal Os of the Cervix can be marginal: close to opening Partial: covers some of the opening Total: complete covering of the opening Bleeding after 20 weeks suspect this Dont perform a digital vaginal examination

Question 29

Week 3

Answer 29

Gasturlation and Neuralation creation of CNS, heart, and Circulatory system usually when mom knows they are pregnant, missing of period

Question 30

Gastrulation

Answer 30

formation of the 3 primary germ layers Ectoderm Mesoderm Endoderm

Question 31

Primitive Streak

Answer 31

Primitive node at top occurs in epiblast migrating and proliferating and pushing down at the streak : cells replace the hypoblast called endoderm and the cells that enter the middle are the mesoderm mesoderm travels all over the layer

Question 32

Prechordal Plate and cloacal membrane are made up of what type of cells

Answer 32

ectoderm and endoderm will not contain mesoderm

Question 33

Septum Transversum

Answer 33

starts in the rostral region | gives rise to the Diaphragm

Question 34

Cardiogenic area

Answer 34

Starts in the rostral region | gives rise to the heart

Question 35

Notochord

Answer 35

mesoderm in the midline starts from the primitive node anterior to the prechordal plate Template for the vertebral column Induces the formation of the neural plat via SHH Migrate from the primitive pit in cephalic dorection go inbetween the ectoderm and endoderm and form a tube called the notochordal process

Question 36

Chordomas

Answer 36

slow going aggressive neoplasms of bone arise from remnants of notochord can occur in spheno-occipital regions of the skull and sacral region

Question 37

Allantois

Answer 37

posterior midline endoderm diverticulm from the wall of yolk sac, connective stalk acts as template for umbilical arteries and veins eventually becomes the urachus

Question 38

Paraxial Mesoderm

Answer 38

Somites: | give rise to muscle, skeleton and Dermis

Question 39

Intermediate Mesoderm

Answer 39

Urogenital, gives rise to kidneys and gonads

Question 40

Lateral plate mesoderm

Answer 40

somatic layer: next to ectoderm Splanchnic layer: lies next to endoderm, give rise to mesoderm supporting the organs

Question 41

Endoderm gives rise to?

Answer 41

``` Lungs and trachea GI tract bladder Thyroid gland Tonsils pharynx ```

Question 42

Ectoderm gives rise to?

Answer 42

Surface Ectoderm: | Neuroectoderm