Practical 3: Development Flashcards
A
Corona radiata
B
Zona pellucida
C
First polar body
D
Chromosomes are separating
E
Anaphase II
F
Metaphase II
A
Spermatozoa entering oocyte
B
Corona radiata
C
Zona pellucida
D
One is the second polar body
The other two are ootids
A
Zygote
B
Yes, a fertilized oocyte
C
Nuclear division
D
Male pro-nucleus
E
Female pro-nucleus
F
Zona pellucida
G
One is the second polar body
The other two are ootids
A
Zygote
B
Yes
C
Spermatozoan
D
Male pronucleus
E
Female pronucleus
A
Two-cell embryo
B
30 Hours old
C
Blastomere
A
Two-cell embryo
B
30 Hours old
C
Zona pellucida
A
Four-cell embryo
B
48 hours
C
Blastomere
A
Four-cell embryo
B
48 Hours
A
Eight-cell embryo
B
60 hours
A
Morula
B
3 days
C
16 cells
D
Totipotent
E
Every blastomere has the potential to develop into a complete individual (as seen in identical twins)
A
Morula
B
3 days
A
Early blastula or blastocyst
B
4 days
C
Hollow
D
Inner cell mass
E
Embryo proper
F
Trophoblasts
G
Human chorionic gonadotropin (hCG)
H
Maintains the corpus luteum, which produces progesterone to maintain the uterus for pregnancy
I
Blastocoel
J
Fluid
A
Early blastula/blastocyst
B
4 days
A
Bilaminar blastula
B
7 days
C
Hollow
D
Nidation
E
Around day 6
F
Trophoblasts
G
Human Chorionic Gonadotropin (hCG)
H
Epiblast
I
Embryo proper
J
Ectoderm, mesoderm, endoderm
K
Hypoblast
L
Extraembryonic endoderm structures like the yolk sac
M
Blastocoel
A
Late blastula
B
8 days
C
Hollow
D
Lacunae
E
Maternal blood
F & G
Syncytiotrophoblasts
H
Invades the uterus to establish the chorion (the fetal contribution to the placenta)
I
Cytotrophoblasts
J
Syncytiotrophoblasts
L
Amnion
M
Thin membrane surrounding the embryo/fetus
N
Amniotic cavity
O
Epiblast
P
Blastocoel
Q
Hypoblast
A
Late blastula
B
8 days
C
Hollow
D
Chorionic cavity
E
Blastocoel
F
Hypoblast
G
Epiblast
H
Amniotic cavity
I
Amnion
J
Cytotrophoblasts
K
Syncytiotrophoblasts
L
Lacunae
A
12 days
B & C
Syncytiotrophoblasts
D
Establish the chorion
E
Cytotrophoblasts
F
Syncytiotrophoblasts
G
Invade the uterus to establish the chorion
H
Amnion
I
Amniotic cavity
J
Epiblast
K
Primary yolk sac
L
Extraembryonic endoderm
M
Mesoderm
N
Hypoblast
A
Trilaminar embryo/gastrula
B
Day 14
C
Secondary yolk sac
D
Connecting stalk
E
Connecting stalk
F
Umbilical cord
G
Chorion
H
Syncytiotrophoblasts
I
Amnion and amniotic cavity
J
Prochordal plate
K
Cephalic region of the embryo (head)
L
Epiblast
M
Secondary yolk sac
N
The primary yolk sac
O
Chorionic cavity
B
28 days
C
5 mm
1/5 inch
D
No, just the limb buds
E
Chorion/placenta
F
Somites
G
Vertebrae, muscles, dermis, cartilage
H
Pharyngeal arches
I
Auditory ossicles, mandible, nerves, hyoid, thymus
J
Thinning
K
Chorionic cavity
L
Secondary yolk sac
M
Primordial germ cells
N
Gonads (ovaries/testes)
O
Chorionic villi
P
Connecting stalk/umbilical cord
Q
Umbilical vessels
A
Embryonic
B
7 weeks
C
Limb buds
B
8-10 weeks
C
22 mm
1 inch
D
No
E
Chorionic cavity
F
Connecting stalk/umbilical cord
G
Secondary yolk sac being resorbed by connecting stalk/umbilical cord
H
Chorion/placenta
I
Amnion
A
Endometrium
B
Morula
D
3 days
E
4-cell stage
F
48 hours
G
Zygote
H
Uterine tube
I
Fertilization
J
Oocyte
K
Metaphase II
L
Ovary
M
Implanting blastocyst
N
Day 6
O
Cervix
A
2
B
Zona pellucida
C
Nucleoli within the nucleus
D
Remnants of 2nd polar body
A
4
A
Morulae
A
Early blastocyst
B
Blastocoel
A
Expanded blastocyst
A
Hatching blastocyst
A
Hatched blastocyst
What does human development depend on?
Temporal and spatial cues in dynamic niches that regulate multiple mesenchymal progenitor cell pools
What do progenitor cells differentiate in response to?
Distinct micro-environmental cues
What is a developing embryo or fetus?
Conceptus
What is the time of development within the uterus?
Gestation
How long is the growing human an embryo?
Day 1 to week 8
How long is the developing human a fetus?
Week 8 until birth
What surrounds the oocyte?
Zona pellucida
What is the fertilized oocyte called?
Zygote
Where does fertilization occur?
In the ampulla of the fallopian tube
When does fertilization happen?
During day 14-15 of a 28 day reproductive cycle
Is the time an oocyte can be fertilized long or short?
Short, as little as 15 hours after ovulation
A two-cell embryo occurs how many hours after fertilization?
30 hours
A four-cell embryo occurs how many hours after fertilization?
48 hours
What is each cell called in an embryo?
Blastomere
What is next after a four-cell embryo?
Eight-cell embryo
What is a solid ball of cells?
Morula
What day does the morula develop?
Around day 3
At what day does the embryo reach the uterus? What stage of development?
4 days (early blastula)
What do trophoblasts differentiate into?
Cytotrophoblasts
What do cytotrophoblasts differentiate into?
Syncytiotrophoblasts
What do syncytiotrophoblasts form?
The chorionic portion of the placenta
What is the zona pellucida made of?
Glycoprotein shell
When does the embryo “hatch” out of the zona pellucida?
Day 4 (when the embryo reaches the uterus)
What does nidate mean?
Implant
What does the inner cell mass become?
The embryo proper
What cells are on the outer wall of the embryo and contribute to the placenta?
Trophoblasts
When does nidation occur?
Day 6-9 after fertilization
Nidation occurs with what stage of development?
Blastula
On what day does the inner cell mass differentiate into two layers?
Day 7
What two layers does the inner cell mass differentiate into on day 7?
Epiblast
Hypoblast
What forms the primary yolk sac?
Hypoblast
How many layers are the syncytiotrophoblasts?
Single layer
How many layers are the cytotrophoblasts?
Single layer
What does the “syncitio” in syncytiotrophoblast mean?
Multinucleated
Which cells are aggressively invasive and digest into the uterus to establish the placenta?
Syncytiotrophoblasts
What day do some lacunae fuse and maternal blood seeps in by?
Day 13
What are the uterine arteries called that deliver nutrients and oxygen to the embryo?
Spiral arteries
When does the chorionic cavity fuse by?
Day 14
When does the secondary yolk sac push down from the hypoblast and cause the primary yolk sac to regress?
Day 14
What is the trilaminar embryo also known as?
Trilaminar embryonic disc and gastrula
When do the primordial germ layers develop by?
Day 15-16
Where do the primordial germ layers develop from?
Epiblast
What is the development of the embryo from zygote to the trilaminar embryo called?
Embryogenesis
What is the development of the primordial germ layers called?
Gastrulation
What is the development of organs and their systems called?
Organogenesis
What are mesodermal masses that lie on either side of the notocord that give the embryo a “segmented” appearance?
Somites
What can be used to “date” the embryo’s progress?
Somites
What are median cylindrical structures that are eventually replaced by the vertebral column?
Notochord
How many pairs of somites are there?
40
What are the 3 parts of the somite?
Sclerotome cells
Dermatome cells
Myotome cells
What do sclerotome cells produce?
Vertebra and ribs
What do dermatome cells produce?
The dermis of the skin on the dorsal part of the body
What do the myotome cells form?
Skeletal muscles of the neck, trunk, and limbs
What do the myotome cells form muscles via?
Limb buds
What is the development of the placenta called?
Placentation
What are the two major components of the placenta?
Chorion
Decidua
What is the fetal contribution to the placenta?
Chorion
What is the maternal contribution to the placenta?
Decidua
What guides the fetal vessels into the uterus?
Chorionic villi
What part of the placenta participates in the exchange of nutrients/wastes/etc?
Decidua
What in the placenta aids in protecting the fetus from maternal immune attack?
Decidua
When does the placenta allow the passage of maternal IgG’s to the fetus as early as?
20 weeks
What takes over progesterone production once the corpus luteum regresses?
The placenta
When does the corpus luteum regress and the placenta takes over progesterone production?
By 8 weeks
What is the embryonic process where the rudiments of the CNS become established?
Neurulation
What is it called when a flat sheet of cells is converted into a hollow tube?
Embryonic folding
What is it called when you sample amniotic fluid with a needle to examine fetal chromosomes?
Amniocentesis
When is amniocentesis done?
10-12 weeks
What do primordial germ cells give rise to?
Gonadal ridge
Hemopoietic stem cells
What does the gonadal ridge give rise to?
Gonads (ovaries, testes)
What does the hemopoietic stem cells give rise to?
Blood cells
What structure becomes part of the umbilical cord and urinary bladder, and is critical in the development of extraembryonic membranes?
Allantois
What is it called when villus cells are biopsied?
Chorionic villus sampling (CVS)
When does CVS occur?
15-18 weeks
At what day does the neural tube form from the neural groove?
Day 18
Where does the neural tube form?
Dorsum of the embryo
When should the anterior portion of the neural tube close?
Day 25
When should the posterior portion of the neural tube close?
Day 27
What is an anterior neural tube defect called?
Anencephaly
What is a posterior neural tube defect called?
Spina bifida
What are NTD indicated by?
Increased alpha fetal protein
What increases NTD risk?
Folic acid deficiency
What is the process of giving birth?
Parturition
What does the fetus release to signal maternal posterior pituitary gland to release oxytocin?
Cortisol
What does oxytocin cause in the mother?
Uterine contractions
