Embryo Flashcards

1
Q

Functions of the plasmalemma (plasma membrane)

3

A
  1. Separation of the cytoplasm from the extracellular fluid
  2. Regulation of exchange of materials with the extracellular environmental.
  3. Sensitivity to chemical changes in the extracellular fluid
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2
Q

Of all newborns w/ anatomical alterations…

A

50% have known cause while 50% have unknown origin.

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3
Q

_% of anatomical alteration have an environmental etiology

A

7%

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4
Q

Examples of environmental Etiology

A
Diabetes 
Infections (Rubella)
Mechanical (radiation) 
Drugs 
Chemicals 
Alcohol
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5
Q

Teratology

A

The science of birth defects

“Terato”= monster

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6
Q

Teratogen

A

Anything that can cause a birth defect

can be a good substance just the wrong dose & time

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7
Q

Embryonic Period

A

From conception to 8 weeks

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8
Q

What happens the last week of the embryonic period?

A

Organogenesis

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9
Q

When do teratogens cause the most birth defects?

A

The embryonic period (organogenesis)

Teratogens can cause malformation of some or all of the organ system

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10
Q

_% of woman who drink while pregnant ?

Their children’s IQ?

A

30%

60

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11
Q

Fetal Alcohol Syndrome symptoms

A

Growth Retardation
Heart Defects
Microcephaly
Mental Retardation

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12
Q

Thalidomide

A
  • Anti-nausea pill
  • Inhibits vessel development
  • Amelia (lack of limbs)
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13
Q

Amelia

A

Complete Lack of Limbs

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14
Q

What is Thalidomide currently being used to treat?

A

AIDS, Leprosy, Leukemia

considered a teratogen

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15
Q

Human Development-Outline

A
  1. Pregenesis (Progenesis/Pro-ontogenesis)
  2. Blastogenesis
  3. Organogenesis
  4. Metamorphosis
  5. Phenogenesis
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16
Q

Pregenesis (In General)

A

Developmental pre-conditions in parents allowing for successful reproduction

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17
Q

Pregenesis Step 1

A

Formation and migration of parental primordial germ cells.

First cells that form (become our gametes)

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18
Q

Pregenesis Step 2

A

Cortico-medullary differentiation of gonads in mother (ovaries) and in father (testes)

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19
Q

Pregenesis Step 3

A

Increase the number of cortico and medullary cells by mitosis

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20
Q

Pregenesis Step 4

A

Gametogenesis (Meiosis) maturation of gametes, fertilization

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21
Q

Cortico and medullary each correlate with which sex?

A

Cortico- Female

Medullary- Males

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22
Q

Migration of Parental Primordial Germ Cells

Leave and go ….

A

Leave Ectoderm and go into the yolk sac wall

? weeks

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23
Q

Migration of Parental Primordial Germ Cells

When and where do they return …

A

When they come back they cross the dorsal mesentery, where gonads are found

(4-6 weeks)

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24
Q

Teratoma

A

When Germ Cells go to extragonadal sites

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25
Q

What can cause teratoma?

A
  1. Chemicals are used to coordinate the migration of the germ cells, the cells are mutant
  2. When primordial germ cells migrate to the wrong place
  3. Defects in gastrulation (totipotent cells)
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26
Q

Meiosis

A

Formation of 4 daughter cells after doubling of DNA and two meiotic divisions

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27
Q

In males when does meiosis occur?

A

Puberty

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28
Q

In females when does Meiosis occur ?

A

germ cells become primary oocytes

Eggs stuck in Meiosis 1 until puberty, Meiosis 2 is completed only when fertilization occurs

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29
Q

Spermatogonia

A

Primordial germ cells in males diploid (46 chromosomes)

SPERMATOGENESIS

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30
Q

Where do spermatogonia orginate from ?

A

Seminiferous Tubule

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31
Q

Oogensis

A

Primordial Germ Cells in female Oogonia

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32
Q

All organelles come from …

A

your mother

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33
Q

Follicular Cells

A

Give nutrients to the oocyte

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34
Q

Meiotic Nondisjunction

A

Irregular distribution of homologous chromosomes t

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35
Q

When does Meiotic Nondisjunction occur?

A
  1. Cell Poles
  2. Failure of paired chromosomes to separate during Anaphase I
  3. Unpaired homologues to the same cell pole (aneupliod)
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36
Q

Aneuploid

A

product of meiosis that result in an abnormal number of chromosomes

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37
Q

Most Common Monosomy

A

(Meiotic Nondisjunciton)

Monosomy X

99% lethal before birth

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38
Q

Most Common Trisomy before birth

A

(Meiotic Nondisjunciton)

Trisomy 16

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39
Q

Most Common Trisomy after birth

A

(Meiotic Nondisjunciton)

Trisomy 21 “Down Syndrome”

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40
Q

The later the Trisomy

A

The greater the chance of survival

19>3

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41
Q

When does nondisjunction usually occur?

A

1st or 2nd meiotic division
(50%)

leading cause of death in early embryogenesis

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42
Q

Ovulation

A

Follicle Rupture

Sticky Cumulus Corona Radiata -second human egg shell, outer protective layer of the ovum

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43
Q

Embryo Phase

A

0-8 weeks

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44
Q

Fetal Phase

A

8-end

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45
Q

Where do eggs get fertilized ?

A

ampulla of the oviduct

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46
Q

Human fertilization requires?

A

~200 sperm and an egg

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47
Q

Normal ejaculation contains?

Infertile?

A

noromal- 250,000,000 sperm

infertile

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48
Q

Capacitation

A

Sperm in female reproductive tract :

  • Gains motility
  • Increases Metabolism
  • Hyaluronidase Enzymatic activity
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49
Q

Barriers Sperm must Penetrate

A

Corona Radiata ->
Zona Pellucida ->
Egg Plasma Membrane

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50
Q

Acrosome Reaction

A

male/sperm reaction

Helps sperm navigate past Corona Radiata, Zona Pellucida, Egg Plasma Membrane

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51
Q

Cortical Reaction

A

Female/Oocyte Reaction.

After fertilization–> increase in Calcium –> prevents polyspermy

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52
Q

Cortical granules

A

located under the egg plasma membrane.

respond by releasing lysomesal enzymes into the space outside of the egg

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53
Q

After fertilization enzymes……

A

change egg membrane and zona pellucida to prevent polyspermy

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54
Q

Pronuclei

A

The fusion of two haploid cells (oocyte and sperm nucleus)

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55
Q

Cleavage

A

After Zygote forms, embryo starts mitosis cell division

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56
Q

Cleavage cell division produces

A

Daughter cells that are 1/2 the size as the parent

2 cells= ½
4 cells= ¼
8 cells=1/8

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57
Q

In cleavage individual cells are called

A

Blastomeres

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58
Q

Fraternal Twins

A

Dizygotic

Two cell embryos cleave so early before the formation of placenta

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59
Q

Identical Twins

A

Monozygotic

Share placenta

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60
Q

What are the three types of twins?

A

Fraternal (dizygotic)
Identical (Monozygotic)
Conjoined

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61
Q

Compaction

A
  1. Outer cells flatten
  2. First Overt Signs of differentiation
  3. Morula is formed
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62
Q

How long does it stay a Zygote

A

until it becomes a two cells (now it is an embryo)

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63
Q

Compaction

outer cells flatten by…

A

Tight junctions btwn. outer cells

Gap junctions link inner cells

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64
Q

Compaction

First overt sign of differentiation

A

Outer cells = placenta

Inner cells= fetus

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65
Q

What is a Morula ?

A

a solid ball of cells resulting from division of a fertilized ovum, blastula is then formed.

due to compaction

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66
Q

When does a Morula form?

A

3-4 days post fertilization

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67
Q

Blastocyst formation depends on

A

Compaction and accumulation of fluid in coel

68
Q

Result of Blastocyst

A

Inner Cell Mass (ICM)
Blastocoel
Trophoblast

(These cells become the fetus)

69
Q

Cavity inside the Blastocyst is called ?

A

Coel, fills up with fluid

70
Q

When the Embryo enters the uterus…

A

3-4 days after fertilization

Still Blastocyst

Embryo encased in zona pellucida

71
Q

Hatching

A

growth required escape from zona pellucida

allows embryo to implant into uterus

72
Q

In hatching what degrades the Zona Pellucida ?

A

Trophoblast secretes degrading enzymes

Outer cells interact w/ uterine environment where uterine secretions degrade ZP

73
Q

Hatching allows for the embryo to…

A

implant into the endometerum of the uterus

day 7

74
Q

“Week of 2s”

A

Second week

Trophoblast:
Cytotrophoblast
Syncytiotrophoblast

Inner Cell Mass:
Epiblast-> Amnion Cavity
Hypoblast -> Yolk sac

75
Q

What do Trophoblast differentiate into?

A

Cytotrophoblast
Syncytiotrophoblast

week of 2s

76
Q

What do Inner Cell Mass differentiate into?

A

Epiblast-> Amnion Cavity
Hypoblast -> Yolk sac

week of 2s

77
Q

Syncytiotrophoblast

A

Highly invasive trophoblast cells that make the placenta

78
Q

Yolk Sac

A

(hypoblastic tissue)

Blood cell precursors and Primordial Germ Cells

Component of Umbilicus

79
Q

Amnion

A

(epiblastic tissue)

Exercise and Cushion Room for the Fetus

80
Q

Chorion

A

Outermost sac of placenta

Exchange btwn fetal & maternal circulation

81
Q

When does Gastrulation occur?

A

Week 3

82
Q

When does the trilaminar embryo occur?

A

Gastrulation

83
Q

What occurs in the of Gastrulation?

A

Formation of the trilaminar embryo:
Epiderm
Mesoderm
Ectoderm

84
Q

When does gastrulation occur?

A

3 weeks

happens quickly

85
Q

What occurs at the start of gastrulation?

A

Formation of the Primitive Streak: Node, Pit, Groove

Neural Groove

Neural Plate

Notochord

86
Q

When does the formation of Paraxial, Intermediate and Lateral plate mesoderm of somitomeres and somites occur?

A

Week 3- Gastrulation

87
Q

What is the groove/ depression on the epiblast called?

A

Primitive Streak

Happens during Gastrulation

88
Q

What happens in Gastrulation

A

Epiblast cells detach and migrate (invaginate) between epiblast and hypoblast layers

89
Q

How does Gastrulation begin?

A

With a depression on the epiblast (primitive streak)

90
Q

Where to all three dermal layer come from?

A

From the Epiblast during Gastrulation

91
Q

Corona Radiata made of

A

Cumulus Cells (sticky cell mass) and Hyaluronic acid

92
Q

Zona Pellucida made of

A

composed of glycoproteins

93
Q

What triggers capacitation ?

A

Triggered by bicarbonate in vaginal secretions ~5 hours

94
Q

What is considered the giver of life?

A

Yolk Sac

95
Q

Placental Barrier doesn’t allow _______ to cross

3

A

Fructose
Protein Hormones
Blood

96
Q

How does gasturlation form the mesoderm germ layer?

A

Epiblast cells detach and migrate in between epiblast and hypoblast

97
Q

How does gasturlation form the endoderm germ layer?

A

Epiblast cell migrate down and displace in the hypoblast

98
Q

How does gasturlation form the ectoderm germ layer?

A

The remaining epiblast cells

99
Q

Which germ layer is epidermis from?

A

Ectoderm

100
Q

Which germ layer is hair and nails from?

A

Ectoderm

101
Q

Which germ layer is sweat and mammary glands from?

A

Ectoderm

102
Q

Which germ layer is Nerevous Tissue from?

A

Ectoderm

103
Q

Which germ layer is Sense Organ from?

A

Ectoderm

104
Q

Which germ layer is Pituitary gland from?

A

Ectoderm

105
Q

Which germ layer is Lens of eye from?

A

Ectoderm

106
Q

Which germ layer is Adrenal Medulla from?

A

Ectoderm

107
Q

Which germ layer is salivary glands from?

A

Ectoderm

108
Q

Which germ layer is Enamel of teeth from?

A

Ectoderm

109
Q

Which germ layer is Epithelium of mouth from?

A

Ectoderm

110
Q

Which germ layer is Epithelium of anus from?

A

Ectoderm

111
Q

Which germ layer is Dermis from?

A

Mesoderm

112
Q

Which germ layer is bone, cartilage, blood form?

A

Mesoderm

113
Q

Which germ layer is epithelium of kidneys from?

A

Mesoderm

114
Q

Which germ layer is the epithelium of gonads from?

A

Mesoderm

115
Q

Which germ layer is the epithelium of vessels from?

A

Mesoderm

116
Q

Which germ layer are Muscles from?

A

Mesoderm

117
Q

Which germ layer is the Adrenal Cortex from ?

A

Mesoderm

118
Q

Which germ layer is Mesothelium from?

A

Mesoderm

119
Q

Which germ layer are Internal Reproductive Organs from?

A

Mesoderm

120
Q

Which germ layer makes the Respiratory Tract?

A

Endoderm

121
Q

Which germ layer makes the Epithelium of theGI tract?

A

Endoderm

122
Q

Which germ layer makes the epithelium of the Bladder/Urethra ?

A

Endoderm

123
Q

Which germ layer makes the liver and gallbladder?

A

Endoderm

124
Q

Which germ layer makes the Thymus?

A

Endoderm

125
Q

Which germ layer makes the Thyroid?

A

Endoderm

126
Q

Which germ layer makes the Parathyroid?

A

Endoderm

127
Q

Notochord

A

Created from gastrualtion.

A signaling machine that is mesodermaly derived

128
Q

What happens in the fourth week?

A

Neuralation

129
Q

Neural Plate

A

Ectoderm induced to differentiate into neural tissue by notochordal process.

130
Q

Neuralation

A

Week 4 (Brain Formation)

Neural plate folds to become a neural tube
Both from ectoderm

131
Q

Somites

A

Blocks of paraxial mesoderm that flank the neural tube

132
Q

Somites form

A

Body and limb muscles
Cartilage in vertebrae and ribs
Cranial bones
Dermis

133
Q

Intermediate mesoderm forms

A

Urinary and parts of the genital system

134
Q

Lateral plate mesoderm forms

A

Trunk only

135
Q

Lateral plate mesoderm associated with

A

Endoderm (Splanchnic mesoderm)

Ectoderm (somatic mesoderm)

136
Q

What sets up the basic body plan?

A

After gasturlation gene expression begins folding of the embryo

137
Q

What two sets of folding occurs in basic body plan?

A

Anterior/posterior: head and tail

Lateral formation of body wall

138
Q

Body folding types

A

Transverse or lateral folding

Cephalocaudal folding

139
Q

Transverse or lateral folding

A

left and right sides of embryo curve toward the midline

3 germ layers fold into cylinder

140
Q

What does transverse or lateral folding create?

A

trunk with endoderm internally and ectoderm externally

141
Q

Cephalocaudal folding

A

Occurs in the head and tail regions

142
Q

Cephalocaudal folding creates …

A

Future head and buttocks

143
Q

Splanchnic mesoderm form

A

Lateral folding

  1. mesentery
  2. wall of digestive tract
144
Q

Somatic mesoderm form

A

Lateral folding

  1. Lateral and ventral body wall
  2. Mesenchyme of limb buds
145
Q

Folding week3-4

A

Purse string constriction

Lateral and cephalocaudal folding

146
Q

Folding weeks3-4 causes

A

Head and tail folds

Blind-ended foregut and hindgut

147
Q

Neural tube derived from …

A

Ectoderm

148
Q

Where does neural tube closure begin?

A

midway along neural plate

149
Q

Where do openings along the neural tube remain ?

A

Cranial and caudal ends

150
Q

Neural tube closures occur at which end?

A
1st anterior (cranial) neuropore 
2nd posterior (caudal) neuropore
151
Q

As the neural plate grows, what decreases?

A

Primitive streak

152
Q

CNS segmentation

A

Brain and spine segments

153
Q

Placodes

A

Thickening of ectoderm that comes from signaling derived by the nervous system

154
Q

Mesodermal development (basic body plan)

A

Mesoderm morphogenesis

Extra embryonic mesoderm

155
Q

Mesoderm morphogenesis

A

Paraxial mesoderm (Somites)
Intermediate mesoderm
Lateral plate mesoderm (lateral folding)

156
Q

Extra embryonic mesoderm

A

Carcinogenic mesoderm

Blood and blood vessels

157
Q

What are the three sections of mesoderm?

A

Paraxial mesoderm
Intermediate mesoderm
Lateral plate mesoderm

158
Q

Paraxial mesoderm forms

A

Somites: muscle, bone, connective tissue of most of the body

159
Q

Intermediate mesoderm forms

A

Urogenital system

160
Q

Lateral plate mesoderm forms

A

Muscle of body wall
digestive tract
Proximal part of limbs

161
Q

Endoderm derivatives require?

A

Integration btwn mesoderm and endoderm

162
Q

What do the endoderm derivatives form?

5

A
Digestive glands (pancreas, salivary glands)
Endocrine glands(thyroid gland)
Respiratory system 
Liver 
Anterior pituitary
163
Q

Endoderm derivatives are a

A

Continuous tube from mouth to anus

164
Q

Oropharyngeal membrane

A

Apoptosis allows for the stomodeum (primitive mouth) to open to the outside

165
Q

Proctodeal membrane

A

Apoptosis allows for the proctodeum (primitive anus) to open to the outside