Fertilization & Gastrulation (EMB) Flashcards

1
Q

What is the embryonic period

A

Week 0 - 8 weeks

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2
Q

What is the obs calender

A

Used in clinical practices

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3
Q

What does the obs calendar ask?

A

When was your LMP

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4
Q

When does ovulation occur?

A

Day 14

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5
Q

When does the ovulatory calendar start?

A

Day 14 (ovulation)

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6
Q

What is the corona radiata

A

Folicular cells that cover the egg

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7
Q

What is the zona pellucida

A

Glycoprotein-meshwork

Very important in the process of fertilization

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8
Q

Human ovum is what type of cell

A

Haploid cell

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9
Q

What is the perivitelline space

A

Space between plasma membrane and zona pellucida

Space where granuales are released from egg cell to aid in zona reaction

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10
Q

Sperm is either what or what

A

23 X or 23 Y

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11
Q

Week one is what days

A

0-7

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12
Q

What happens during week one

A

Fertilization, cleavage, formation of blastocyst, formation of embryoblast, and implantation

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13
Q

Fetilization occurs where

A

In the ampulla

Distal 3rd of the uterine tube

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14
Q

What is capacitation and where does it occur

A

Occurs in uterus and uterine tube

Glycoprotein coat on head of sperm is removed, allowing for an acrosome reaction to occur (release enzymes from enzymes)

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15
Q

What is hyaluranidase

A

Enzyme released by sperm to get through corona radiata

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16
Q

Step 1 of fertilization

A

Capacitaiton of sperm, release of hyaluronidase

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17
Q

Step 2 of fertilization

A

Penetration of zona pellucida by the release of estrases, acrosin, and neuraminidase from acrosome

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18
Q

What is a zona reaction

A

Blockage of access to ovum by other sperm to prevent polyspermy

This occurs by a conformational change

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19
Q

Step 3 in fertilization

A

Fusion of sperm with cytoplasm in ovum

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20
Q

Step 4 in fertilization

A

Formation of male pronucleus, fusion of female and male pronuclei

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21
Q

What are the cells called that are cleaved?

A

Blastomeres

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22
Q

What happens during cleavage

A

Increase in cell number, but a decrease in cell size

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23
Q

When does cleavage start

A

Aprox. 30 hours after fertilization

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24
Q

What is a morula and when does it occur

A

12 - 32 cells packed together

Occurs about day 3

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25
Q

When does morula enter uterine cavity

A

Day 3

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26
Q

Morula becomes what

A

Blastocyst (no zona pellucida and with a blastocyst cavity)

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27
Q

Fusion of male and female pronuclei make a what

A

Zygote (pluripotent)

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28
Q

Implantation begins when

A

Day 6

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29
Q

When in zona pellucida completely gone

A

Day 7

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30
Q

The inner cell mass gives rise to what

A

Embryo

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31
Q

The trophoblast gives rise to what

A

The placenta

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32
Q

The blastocyst is considered what at the end of week one

A

A one layer cell

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33
Q

Trophoblast cells release what to protect cell

A

Early pregnancy factor

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34
Q

Trophoblast cells differentiate to give rise to what

A

Cytotrophoblast

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35
Q

Cytotrophoblast gives rise to what

A

Syncytiotrophoblast

36
Q

What does the syncytiotrophoblast do

A
  1. Release proteolytic enzymes which allows for implantation

2. Release hcg - tells woman’s body that she is prego (is basis for prego test)

37
Q

What does the cytrotrophoblast do

A

Makes stem cell layer which is mitotically active

38
Q

Hydatidiform mole

A

Abnormal trophoblast proliferation due to excess amount of hCG

TWO TYPES

39
Q

Complete mole

A
  1. Fertilization of an empty oocyte followed by duplication of the sperm
40
Q

Partial mole

A

Results from the fertilization of a normal oocyte by two sperm

This is due to a faulty zona reaction

Presents as vaginal bleeding, pelvic pain, enlarged uterus, and hyperemesis gravidarum

41
Q

Inner cell mass gives rise to what two things

A

Epiblast and hypoblast

42
Q

Epiblast gives rise to what

A

Ectoderm, amnion, and amniotic cavity

43
Q

Hypoblast is only present when

A

During week two

44
Q

They hypoblast gives rise to what

A

Endoderm - extraembryonic

Primary and secondary yolk sack (umbilical vesicle)

Extraembryonic mesoderm

45
Q

What does the endoderm give rise to

A

Prechordal plate - location of the future mouth and organization center for the head

46
Q

What is the difference between primary and secondary yolk sacks

A

Timing, primary comes first

47
Q

What is the extraembryonic coelom

A

Hollow cavity outside the embryo

48
Q

Two types of mesoderm

A

EE somatic Mesoderm

EE splanchnic Mesoderm

49
Q

Extraembryotic Somatic mesoderm

A

Lines the trophoblast and covers the amnio

Next to cells of ectoderm

50
Q

Extraembryonic splanchnic mesoderm

A

Lines the yolk sac

51
Q

Connecting stalk

A

Part of the extraembryonic somatic mesoderm

Forms the embryonic pole and umbilicus

Position changes during development

52
Q

Primitive blood

A

Comes from EE splanchnic mesoderm

Forms in the wall of the yolk sack

53
Q

Chorion

A

Comes from the EE somatic mesoderm

54
Q

Broad over view, what happens in week 1, 2, and 3

A

Wk. 1 - formation of inner cell mass

Wk. 2 - formation of epiblast and hypoblast

Wk. 3 - gastrulation (formation of 3 germ layers)

55
Q

When will female know if she is pregnant

A

Week 3

56
Q

All germ layers come from what

A

Epiblast

57
Q

Things that come from ectoderm

A

Skin, hair, nails, brain, SC

58
Q

Things that come from mesoderm

A

Muscle, bone, blood, heart, spleen

59
Q

Things that come from endoderm

A

Lungs, GI system, bladder, thyroid glands

60
Q

What are the three germ layers

A

Ectoderm
Mesoderm
Endoderm

61
Q

Primitive streak starts where

A

Caudil region

62
Q

What forms first, precordial plate and chloaca or prim. Streak?

A

Precordial plate and chloaca

63
Q

The primitive streak does what

A

Replaces hypoblast with true endoderm

Makes true mesoderm

64
Q

Cells on top in epiblast become what

A

Ectoderm

65
Q

The septum transversum becomes what

A

Future diaphragm

66
Q

The prechordial plate and cloacal membrane do not have what

A

Mesoderm (no blood supply)

They rupture

67
Q

What does the somatic mesoderm cover

A

The trophoblast and the amnion

68
Q

What does the splanchnic mesoderm cover

A

The yolk sack

69
Q

The cloacal membrane becomes what

A

The anus, it falls off and opens up

70
Q

What is a sacrococygeal teratoma

A

Remanent of the primitive streak that protrudes out due to pluripotent cells

OR

Abnormal germ cell migration

71
Q

What is the notochord

A

Template for vertebral column

72
Q

Where does the notochord extend from

A

Extends midline from primitive pit to prechordal plate

73
Q

What does the notochord do (3 things)

A

Provides longitudinal axis for embryo

Provides template for vertebral column

Induces formation of neural plate and CNS

74
Q

The notochord is a what structure

A

Mesodermal structure

75
Q

Describe the formation of the notochord

A

Cells forming notochord migrate from primitive pit in a cephalic direction

Notochordal process forms and fuses with endoderm and forms the notochordal plate which connects the yolk sack with the amniotic cavity

Notochrod cells reform and form the notochord proper

76
Q

What is a chordoma

A

Rare slow growing aggressive neoplasms of bone

77
Q

What do chordomas arise from

A

Remnants of the notochord

78
Q

What is the allantois

A

Diverticulum coming from yolk sack

79
Q

What is allantoid made of

A

Endoderm

80
Q

What does the allantois do

A

Becomes template for umbilical arteries and veins as well as urachus

81
Q

What is paraxial mesoderm and where is it located

A

Located just adjacent to notochord

Gives rise to structures called somites

82
Q

What are somites and what do they give rise to

A

Part of paraxial mesoderm

Gives rise to myotome (muscle), sclerotone (bone) , and dermatone (skin)

83
Q

What is the intermediate mesoderm and where is it located

A

Gives rise to urogenital (kidneys and gonads) and located between paraxial mesoderm and lateral plate

84
Q

What is lateral plate and where is it located

A

Located on the extreme end of the mesoderm

Gives rise to connective tissue

85
Q

What are the two layers of the lateral plate

A
  1. Somatic - adjacent to ectoderm (on top)

2. Splanchnic - adjacent to endoderm (on bottom)