Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BMS > Human Embryogenesis: Weeks 1-3 of Prenatal Development > Flashcards

Human Embryogenesis: Weeks 1-3 of Prenatal Development Flashcards

(83 cards)

Start Studying
1
Q

The embryogenesis and embryonic period occurs from

A

Week 1-8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The fetal period occurs from

A

Wee 9-38

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

At the center of the 28 day menstrual cycle and its phases

A

Ovulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The ovulated oocyte is surrounded by a shell with

A

Layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Spermatozoa are conditioned in the female tract to be able to fertilize the oocyte. This is called

-sperm that do not undergo are unable to fertilize

A

Capacitation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Fertilization occurs where the oocyte and capacitted sperm meet, which is in the

A

Ampulla of uterine tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Sperm can live in the female tract for several days, but an oocyte that is not fertilized degenerates within

A

24 hours of ovulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Implantation of the early embryo is during endometrial secretory phase. If pregnancy occurs, the corpus luteum is maintained for a period by

A

Human chorionic gonadotropin (hCG)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Secreted by trophoblasts of the placenta

A

hCG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the three “shell” layers of the oocyte?

A
  1. ) Corona Radiata (outer)
  2. ) Zona Pellucida
  3. ) Plasma membrane (inner layer)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Outer crown of follicular cells around oocyte

-has chemoattractants for sperm

A

Corona Radiata (cumulus oophorus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the functions of the corona radiata?

A

Provides protection, energy, and support for oocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Intermediate glycoprotein layer made up of “zona proteins” (ZP)

A

Zona Pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The zona protein ZP3 binds

A

Sperm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Sperm are modified by secretions in the female tract.
These modifications take several hours and make up
a mandatory “ripening” process for fertilization called

A

Capacitation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Removed at the tip of the sperm head during capacitation to make the membrane overlying the acrosome more fluid for enzyme release during fertilization

A

Glycoproteins and Plasma Proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Become hyper-active during capacitation

A

Sperm tails

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the three phases of fertilization?

A
  1. ) Penetration of corona radiata
  2. ) Penetration of zona pellucida
  3. ) Plasma membrane fusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Capacitated sperm penetrate the corona radiata via the

-only 300 of the 300 million sperm ejaculated penetrate the corona radiata

A

Whipping sperm tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

In phase 2, sperm heads bind to the ZP3 receptors in the zona pellucida and release acrosomal enzymes that allow

A

Penetration of zona pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

In phase 3, the sperm and oocytes plasma membranes fuse. The oocyte completes meiosis II and the female gamete (ovum) and male gamete (sperm) fuse their haploid pronuclei to form a

A

Diploid zygote

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens to the oocyte plasma membrane upon sperm contact?

A

It depolarizes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Intracellular Ca2+ tsunami that induces the cortical reaction

-prevents polyspermy (more than one sperm binding)

A

Oocyte PM depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

At the initiation of cleavage, the zygote is metabolically activated and will soon mitotically divide into

A

2 cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Two oocytes are simultaneously ovulated and each is fertilized by separate sperm -70% of all twins
Dizygotic twins (DZ)
26
A single zygote is fertilized by a single sperm and splits into 2 zygotes within the 1st week after fertilization -30% of all twins
Monozygotic Twins
27
A series of symmetrical mitotic divisions during week 1
Cleavage
28
Cleavage divisions occur approximately 20 hours apart and results in
Blastomeres
29
Daughter cells which are smaller w/ each successive division and are encased by the zona pellucida in the early embryo
Blastomeres
30
Cleavage continues and blatomeres up through the 8-cell stage are -can give rise to all embryonic and extraembryonic tissues
Totipotent
31
Beyond the 8 cell stage, cells become more differentiated and are committed to being a
Particular cell type
32
By day 4, the 32-cell morula (“mulberry”) is a solid ball of compacted cells migrating in the uterine tube toward the
Uterus
33
The cells of the morula segregate and begin to establish polarity. What is the: 1. ) Inner cell mass (ICM) 2. ) Outer cell mass (OCM)
1. ) Embryoblast | 2. ) Trophoblast
34
Fluid from the uterine cavity penetrates the zona pellucida to surround cells of the morula’s embryoblast/ICM. By 4.5 days after fertilization, the penetrating fluid pools and forms the
Blastocyst cavity of the blastocyst
35
Embryoblast/ICM cells can give rise to any/all embryonic cells, meaning they are
Pluripotent
36
Pluripotent embryoblast/ICM cells have great clinical potential as
Embryonic stem cells
37
Occurs 6 days after fertilization during the secretory phase of the endometrium (day 20 of 28 day cycle)
Blastocyst Implantation
38
Secrete enzymes that degrade the zona pellucida, allowing the blastocyst to hatch through the zona pellucida on day 5
Trophoblasts
39
Drive blastocyst implantation -located at embryonic pole of the blastocyst
Trophoblasts
40
Trohphoblasts at the embryonic pole of the blastocyst embed into the uterine wall and eventually form fetal components of
Placenta
41
Induces the corpus luteum to continue secretion of progesterone for endometrium maintenance -Secreted by trophoblasts
Human Chorionic Gonadotropin (hCG)
42
With implantation, the pregnant uterine endometrium undergoes a
Decidua reaction
43
The blastocyst normally implnts on the anterior or posterior unterine body wall. In 2% of pregnancies, implantation occurs elsewhere. This is called
Ectopic pregnancy
44
95% of ectopic pregnancies occur in the
Uterine Tube
45
A busy time for cleavage and segregation of blastomeres before implantation in the uterine endometrium
Week 1
46
A busy time for trophoblasts , hypoblasts, and amnioblasts in forming extraembryonic support
Week 2
47
The ebryoblast forms the 2-layered/bilaminar disc during
Week 2
48
Embyoblast differentiation forms the
Bilaminar embryonic disc
49
What are four extraembryonic structures developed during week 2?
1. ) Amniotic Cavity 2. ) Yolk sac 3. ) Connecting Stalk 4. ) Fetal part of placenta
50
Differentiate into cells of the embryo proper and amnioblasts
Epiblasts
51
Is located dorsal to the bilaminar disc, but expands
Amniotic cavity
52
What are three components of amniotic fluid?
1. ) Fetal urine 2. ) Oligohydraminos 3. ) Polyhydraminos
53
Proliferate and migrate to line the inner trophoblast surface of the blastocyst cavity, which becomes the yolk sac
Hypoblasts
54
Located ventral to the bilaminar disc, and eventually regresses
Yolk sac
55
The location of early exchange, early hematopoiesis, and germ cell conversion to gonads
Yolk sac
56
Hypoblasts give rise to which two things?
1. ) Yolk sac | 2. ) Connecting Stalk
57
Becomes the umbilical cord and connects the embryo/fetus to the placenta
Connecting stalk
58
Develops from the trophoblast-altered endometrium
Maternal placenta
59
A composite organ that facilitates nutrient and gas exchange between the maternal and fetal compartments
Placenta
60
What is the: 1. ) Fetal part of placenta 2. ) Maternal part of placenta
1. ) Chorion fondosum (trophoblasts & hypoblasts) | 2. ) Decidua basalis (uterine endometrium)
61
In fetal blood, moves to the placenta from the umbilical arteries
Waste
62
In fetal blood, moves from the placenta to the umbilical vein
Nutrients
63
In maternal blood, nutrients move to the placenta from
Spiral arteries
64
In maternal blood, waste moves from the placenta to the
Uterine veins
65
There is waste-nutrient exchange and separation (no mixture) of fetal and maternal blood at the
Thin placental barrier
66
A busy time for epiblasts in formation of intraembryonic germ layers
Week 3
67
In week 3, the epiblast of the bilaminar embryo forms the 3-layered/trilaminar disc in a process called
Gastrulation
68
Epiblast cells migrate to the primitive streak where they detach and invaginate (dive down ventrally) through the primitive streak during
Gastrulation
69
The three primary germ layersof the trilaminar embryo are the -originate from epiblast
Ectoderm, mesoderm, and endoderm
70
The process of forming the endoderm, mesoderm, and ectoderm
Gastrulation
71
Epiblast cells that intercalate among hypoblast cells displace and completely replace hypoblast cells to form the
Endoderm
72
Epiblast cells settle between the endoderm and epiblast to form the intraembryonic
Mesoderm
73
Epiblast cells that remain behind then become the
Ectoderm
74
Polarity (i.e. dorsal-ventral, right-left, cranial-caudal) is established during
Gastrulation
75
Becomes structures that communicate with the external environment -i.e. nervous system, epidermis, and sensory receptors
Ectoderm
76
Becomes a component of support through muscles and connective tissues -i.e. skeletal, muscular, urogenital, and cardiovascular
Mesoderm
77
Functions in digesting, breathing, and secreting -i.e. epithelia of urinary bladder and GI-respiratory systems
Endoderm
78
Organs are derived from more than one
Germ layer
79
What are the two sites in the embryo where the ectoderm and endoderm adhere tightly together without migration of intervening mesoderm?
Buccopharyngeal membrane and cloacal membrane
80
Lies at the cranial end of the embryo as the future location of the oral cavity
Buccopharyngeal membrane
81
Lies at the caudal end of the embryo as the future location of the anus
Cloacal membrane
82
The primitive streak regresses by the end of the 3rd week with the formation of the
Notochord
83
Form when the primitive streak fails to completely regress and contain multiple tissue types derived from the pluripotent epiblast cells
Teratomas

BMS (62 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions