Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BMS150 Test 2 > Embryology 1 - Fertilization to Gastrulation (Week 8) > Flashcards

Embryology 1 - Fertilization to Gastrulation (Week 8) Flashcards

1
Q

True or False: We start out as one totipotent cell

A

True

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

An organism that breathes no air, does not use the digestive tract, and lives in a sterile environment is referred to as what?

A

a fetus

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

An air-breathing organism with a functional GI tract that quickly becomes colonized by microbial flora is referred to as what?

A

a newborn

Note: we undergo these massive changes within minutes after birth

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

True or False: Learning embryology helps us to understand developmental/congenital disorders (e.g., DiGeorge Syndrome, ectopic pregnancy, neural tube defects, etc.), infertility, and referred pain

A

True

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

Where are oocytes (female haploid gametes) produce?

A

the ovaries

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

Production of which hormones occurs in the ovaries?

A

progesterone and estrogens

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

Which structure receives the oocyte from the ovaries?

A

the uterine tube/fallopian tube

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

Where does the sperm fertilize the oocyte?

A

the uterine tube/fallopian tube

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

Where do the embryo, placenta, and membranes develop?

A

the uterus

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

The site where the maternal and embryonic vasculature exchange substances

A

the placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

A __________ (haploid/diploid) germ cell undergoes meiosis to produce a unique __________ (haploid/diploid) gamete

A

diploid, haploid

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

How do haploid gametes become “unique”?

A

crossing over (mixing of maternal and paternal chromatids during prophase I to end up with “mixed” chromatids)

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

True or False: Meiosis is completed before the sperm penetrates the oocyte

A

False.

Meiosis is not completed in an oocyte UNTIL the sperm penetrates it

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

We can refer to the fusion of the spermatic pronucleus and the oocyte pronucleus as?

A

fertilization

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

A single, fertilized, diploid cell (combination of spermatic and oocyte genetic material = diploid cell) is known as?

A

a zygote

Note: a zygote has NOT divided yet

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

Females are born with a certain number of diploid oocytes that have been “paused” at what stage?

A

first stage of meiosis

Note: meiosis does not resume until AFTER puberty

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

After puberty, the ovaries release an _______ each cycle into the uterine tubes

A

ovum

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

The oocyte will not complete meiosis II unless ____________ occurs

A

fertilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In what part of the uterine tube specifically does fertilization usually occur?

A

the ampulla

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

Before ovulation, we call the oocyte what?

A

primary oocyte

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

After ovulation, we call the oocyte what?

A

secondary oocyte

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

The release of a secondary oocyte from the ovarian follicle is known as?

A

ovulation

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

The ovulated secondary oocyte + the zona pellucida is covered externally with granulosa cells known as what?

A

cumulus oophorus

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

When the cumulus oophorus rearranges, it forms the what?

A

corona radiata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

A successful sperm must penetrate the _____________ and inject its genetic material into the oocyte

A

zona pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

True or False: Zona pellucida becomes impenetrable after first sperm penetrates it

A

True

Note: this prevents “double fertilization”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How long after fertilization does the oocyte complete meiosis II + zygote completes first cell division?

A

24 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

A morula consists of how many cells?

A

12-20 cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

A ___________ is what implants into the uterine wall

A

Blastocyst

(formed around day 5)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

When sperm comes into contact with the zona pellucida, it triggers an acrosome reaction, whereby the sperm secretes ___________________, that will break down the glycoprotein membrane of the zona pellucida

A

digestive enzymes

Note: only 1 sperm will succeed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

a haploid germ cell is also known as

A

a gamete

(oocyte = gamete from ovaries; sperm = gamete from testes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

the protein coat that surrounds an oocyte and eventually the early embryo

A

zona pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

a multicellular organism, prior to the fetal stage (~ from fertilization to end of week 7) is known as?

A

an embryo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

a multicellular organism, from the end of the embryonic stage (week 8) to birth is also known as?

A

a fetus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

___________ is another name for newborn

A

neonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

cells formed during development that do not become part of the neonatal organism (but contribute to the fetal membranes)

A

extraembryonic cells

note: eventually contributes to the placenta

37
Q

16 cell stage of an embryo

A

morula

note: no blastocoel in this stage

38
Q

a spherical mass of cells that is composed of a trophoblast that surrounds a fluid cavity (blastocoel) and an inner cell mass (embryoblast)

A

blastocyst

39
Q

What do we call the cell division in the early embryo, whereby each division does not increase the size of the embryo but instead results in smaller and smaller cells?

A

cleavage

40
Q

a cell that is totipotent and is present during very early development (e.g., first week) is called?

A

blastomere (every single cell that makes the embryo in the first week)

41
Q

a cell that can become any cell

A

totipotent cell

42
Q

when the embryo contacts and becomes surrounded by the endometrium of the uterus

A

implantation

43
Q

Days 1-3 of development

A
  • embryo develops from zygote to a sphere-shaped cluster of cells surrounded by the zona pellucida
  • 12-32 cell stage (morula)
  • cell divisions known as cleavage
  • cells known as blastomeres (which are all genetically identical = embryonic stem cells)
44
Q

Days 4-5 of development

A
  • a fluid-filled cavity develops within the embryo
  • four structures can be noted:

1) trophoblast (layer of cells on the outside of the sphere, covered by the 2) zona pellucida); many of these cells go on to develop into membranes of placenta

3) embryoblast (inner cell mass); surrounded by the trophoblast; these cells develop into the embryo

4) blastocoel (the fluid-filled cavity within the sphere)

45
Q

The epithelial cells of the uterine tube are equipped with _________ that “wave” in a single direction

A

cilia

Note: ciliary movement increases as progesterone levels increase (secretion peaks shortly after ovulation)

46
Q

Where does the blastocyst arrive after about 5 days?

A

the superior aspect of the uterus (the fundus)

47
Q

What are some of the roles of the zona pellucida during early development?

A
  • barrier that ensures only one sperm fertilizes an oocyte
  • porous (allows communication between the embryo and the maternal reproductive structures
  • protects the embryo from immunologic defenses
  • acts as a signal to help with differentiation of trophoblast cells
  • prevents premature implantation of the embryo
  • prevents the blastomeres from dissociating (helps them stay together)
48
Q

When does the embryo “hatch” out of the zona pellucida?

A

day 6

Note: the zona pellucida prevents implantation of the embryo, but once it hatches, it is ready to come into contact with the endometrium and implant itself

49
Q

What is a complication that can happen when the embryo implants too early?

A

ectopic pregnancy

50
Q

What part of the endometrium binds to the trophoblast of the blastocyst?

A

small apical processes known as pinopods

Note: adhesion is mediated by selectin (which binds to mucins expressed on the endometrial epithelium) and integrin binding

.. results in blastocyst invading into the endometrium

51
Q

Once the trophoblast invades the endometrial epithelium, it forms two layers: _____________ and ________________

This occurs during ~ day 5-6

A

cytotrophoblast (inner layer),

syncytiotrophoblast (outer layer)

52
Q

The syncytiotrophoblast develops into a ___________ (mononuclear/multinuclear) cell mass where the borders between cells are indistinct (looks more like a blob)

A

multinuclear

53
Q

What does the syncytiotrophoblast secrete?

A

human chorionic gonadotropin (hCG)

Note: hCG prevents the shedding of the endometrium (and loss of the embryo) by maintaining ovarian secretion of steroid hormones (e.g., progesterone)

Note: hCG is the hormone detected in pregnancy tests

54
Q

As the syncytiotrophoblast invades the stroma (just below the epithelium), the _______________ (aka embryoblast) differentiates into two distinct layers: ____________ and ______________

This happens @ ~ day 6-7 (end of week 1)

A

inner cell mass,

epiblast (becomes the actual embryo/”embryo proper”),

hypoblast (aka “primary endoderm”; lines the blastocystic cavity and forms the primary yolk sac)

55
Q

a fluid-filled cavity

(week 2 & 3)

A

coelom

56
Q

the process of forming three embryonic germ layers

A

gastrulation

57
Q

What are the 3 embryonic germ layers?

A

1) ectoderm (exterior)
2) endoderm (interior)
3) mesoderm (between ectoderm and endoderm)

58
Q

True or False: the endoderm and mesoderm can also be extra-embryonic. The formation of extra-embryonic endoderm and mesoderm is NOT classified as gastrulation.

A

True

59
Q

towards the head region

A

cephalad

60
Q

towards the “tail” region

A

caudad

61
Q

When is implantation complete (approximately)?

A

day 10

62
Q

umbilical vesicle is synonymous with what?

A

yolk sac

63
Q

Stromal cells undergo decidualization and become known as decidual cells.

Decidual cells accumulate _________ and __________ throughout the uterus

A

glycogen, lipids

64
Q

Any time the syncytiotrophoblast contacts a decidual cell, the decidual cell is programmed to undergo ___________

A

apoptosis

Note: this releases the stored nutrients (glucose and lipids) so that the embryo has nutrients to grow

65
Q

The epiblast enlarges and gives rise to _______________

A

amnioblasts (cells that surround the developing amniotic cavity)

66
Q

Fluid accumulating between the extraembryonic mesodermal cells to form another cavity is known as the what?

A

extraembryonic coelom

67
Q

three fluid-filled cavities that develop in the embryo:

A

1) umbilical vesicle (yolk sac)
2) amniotic cavity
3) extraembryonic coelom (develops into the chorionic cavity)

68
Q

The connecting stalk eventually develops into what?

A

the umbilical cord

69
Q

What are the two layers of the extraembryonic mesoderm?

A

1) extraembryonic splanchnic mesoderm (surrounds the umbilical vesicle)

2) extraembryonic somatic mesoderm (just underneath the cytotrophoblast, inner lining of the chorionic sac)

70
Q

What is the chorion/wall of the chorionic sac comprised of?

A
  • extraembryonic somatic mesoderm
  • trophoblast (syncytiotrophoblast + cytotrophoblast)

Note: the chorionic SAC is everything inside of this

71
Q

The chorionic sac encloses the ___________ and its cavities

A

embryo

72
Q

The extraembryonic coelom becomes the ____________ by day 14

A

chorionic cavity

73
Q

When syncytiotrophoblasts contact endometrial blood vessels, the blood vessel deteriorates and blood pools

These “little lakes” of blood are known as what?

A

lacunar networks

Note: these allow for more exchange of nutrients

74
Q

How do nutrients from the oxygenated maternal blood and deteriorating decidual cells get to the embryo?

A

simple diffusion

Note: there is no circulation yet

75
Q

thickened area of columnar cells, found in the cephalad region of the hypoblast, that acts as an embryonic organizing centre and is responsible for the induction of other structures

A

prechordal plate

Note: this forms by the end of week 2 (day 14)

76
Q

True or False: the hypoblast is an organizer of the caudal aspect of the embryo

A

False.

The hypoblast organizes the head and mouth region and helps to induce the formation of structures found at the cephalad pole of the embryo

77
Q

the process by which the three germ layers of the embryo are established

A

gastrulation

78
Q

During gastrulation, the bilaminar embryonic disc becomes the _____________

A

trilaminar embryonic disc

79
Q

During gastrulation, the embryo may be referred to as the _________

A

gastrula

80
Q

thickened linear band in the median plane of the dorsal aspect of the embryonic disc that forms at the beginning of the 3rd week

A

primitive streak

81
Q

True or False: The primitive streak initiates the caudal region of the epiblast

A

True

82
Q

Cells at the cephalad end of the primitive streak proliferate to form what?

A

primitive node

83
Q

A narrow groove that develops in the primitive streak

A

primitive groove

Note: primitive groove is continuous with a small depression in the primitive node, known as the primitive pit

84
Q

As the cells leave the deep surface of the streak, they form what?

A

the mesenchyme

85
Q

What is mesenchyme?

A

embryonic connective tissue which forms the supporting tissues of the embryo (i.e., embryonic connective tissue)

Note: mesenchyme –> forms mesoblastic cells –> which form intraembryonic or embryonic mesoderm

86
Q

When the hypoblast is displaced by cells from the epiblast, it forms what?

A

embryonic endoderm

87
Q

Cells remaining in the epiblast form what?

A

embryonic ectoderm

88
Q

___________ cells derived from the primitive streak migrate widely and differentiate into diverse types of cells (e.g., fibroblasts, chondroblasts, osteoblasts, etc.)

A

Mesenchymal

89
Q

True or False: Eventually, the primitive streak diminishes in size and becomes an insignificant structure in the sacrococcygeal region, and disappears by the 4th week

A

True

BMS150 Test 2 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions