Embryology Flashcards

1
Q

Medulla of gametes

A

Cortex- female

Testes- male

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2
Q

Synthetic enzyme for removal of corona radiata

A

Hyolase

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3
Q

Enzymes in the acrosome that penetrate zona pellicuda by forming acrosomal reaction

A

Hyaluronidase
Acrosin
Trpsin like enzyme

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4
Q

Sperm abnormalities

A

Morphological: multiple heads and tail, fused sperms, gigantic or dwarfed sperms.
Genetic (rare)
Motility

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5
Q

Interphase of mitosis

A

DNA replication of chromosomes

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6
Q

Prophase of mitosis

A

Disappearance of nucleolus

Appearance of chromatids (indistinguishable)

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7
Q

Prometaphase of mitosis

A

Chromatically visible (distinguishable)

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8
Q

Metaphase of mitosis

A

Nuclear membrane breaks
Arrangement of chromosomes at equator
Appearance of spindle fibers from centrioles

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9
Q

Anaphase of mitosis

A

Splitting of centromere

Pulling of daughter chromosomes to opposite poles

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10
Q

Telophase of mitosis

A

Appearance of nucleolus
Formation of nuclear membranes
Cytokines and formation of 2 diploid cells

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11
Q

Prophase of meiosis

A
Leptotene
Zygotene 
Pachytene 
Diplotene
Diakenesis
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12
Q

Ootid?

A

An oocyte containing two haploid nuclei

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13
Q

Capacition of sperms

A

Removal of glycoproteins and seminal plasma proteins surrounding the acrosomal region of a sperm

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14
Q

Agenesis

A

refers to the failure of an organ to develop during embryonic growth and development due to the absence of primordial tissue.

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15
Q

Tunica Abuginea

A

White capsule surrounding the testes that extends inwards and divides it into different lobes

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16
Q

What secretes Testosterone?

A

Interstitial cells of Leydig

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17
Q

Contents of prostatic fluid

A
Prostaglandins 
Acid phosphate
Citric acid
Prostate specific antigen
Amylase
Fribrinolysin
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18
Q

What secrets HCG?

A

Syncytiotrophoblast

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19
Q

Role of HCG

A

Indicates pregnancy

Retains the corpus luteum in order to continue secreting progesterone

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20
Q

Siamese

A

Conjoined twins

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21
Q

Conjoined twins at the chest are called?

A

Thoracopagus

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22
Q

How many hours does fertilization take approximately?

A

24hrs

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23
Q

When does cleavage begin?

A

In the uterine tube 30 hours after fertilization

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24
Q

When the primary chorionic villi formed?

A

Day 13

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25
Q

When is the prechordal plate formed?

A

Day 14

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26
Q

What induces zona/ cortical reaction?

A

Lysosomal enzymes released from cortical granules of the plasma membrane to penetrate the PM and prevent other sperms from passing through it or the ZP

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27
Q

What is closing plug?

A

A fibrous coagulum of blood at the site where the embryo sank into the endometrium

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28
Q

Placenta previa

A

Placenta that covers or blocks the os due to implantation at the inferior segment of the uterus near the internal os

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29
Q

Life spans of spermatozoa and oocyte respectively

A

72hrs

48hrs

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30
Q

Site for capacitation of sperms and time taken to complete it

A

Fallopian tube

5-7hrs

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31
Q

What aids the penetration of corona radiata

A

Tail movements

Mucosal enzyme hyaluronidase

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32
Q

Acrosome reaction

A

Release of acrosomal enzymes (HAT) for penetration of ZP

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33
Q

Totipotent

A

Capable of forming a complete embryo

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34
Q

Morphogenesis

A

Formation of body form due to gastrulation

Stimulated by morphogenic proteins, FGFs and Wnts

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35
Q

Sacrococcygeal teratoma

A

Persistence of primitive streak
Forms a tumor containing tissues from a three germ layers
Common in females
1 in 35,000

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36
Q

Vasculogenesis vs angiogenesis

A

Formation of new blood vessels from cell precursors called angioblast
Formation of new blood vessels from preexisting vessels

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37
Q

Amniocentesis

A

Amniotic fluid sampling to detect genetic disorders

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38
Q

Ultrasonography

A

Image modality for evaluation of the fetus to detect anomalies, measure size, etc

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39
Q

Alpha fetoprotein

A

A glycoprotein synthesized in the liver, umbilical cord and gut of the fetus.
High level of AFP in fetal serum indicates anomalies of CNS and ventral abdominal wall.
Low level in maternal serum indicates trisomy

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40
Q

Factors that affect fetal growth

A
Cigarette smoking 
Use of illicit drugs
Multiple pregnancy
Impaired uteroplacental/ fetoplacental blood flow
Genetic factors
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41
Q

Ways of monitoring fetal status

A
Ultrasonography 
Amniocentesis 
Chorionic villus sampling
MRI and CT 
Spectrophotometric studies 
Sex chromatin
Alpha fetoprotein
Percutenous Umbilical cord blood sampling 
Fetal transfusion 
Fetoscopy
Fetal monitoring
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42
Q

Functions of placenta

A

Metabolism
Secretion of hormones
Transfer of nutrients and gases

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43
Q

Unfertilized secondary oocyte will last for?

A

24 - 48hrs in the ampulla

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44
Q

Amount of sperm in an ejaculate

A

200 - 350 million

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45
Q

Movement of ovum from ovary into uterine tube is by?

A

Sweeping of the fibria on the ovary

Cilia of the mucosal lining

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46
Q

Movement of ovum within uterine tube to the ampulla is by?

A

Peristaltic contractions of the tube

47
Q

How does ph of vagina affect sperms?

A

Slows them down due to it’s acidity

Sperms are faster in the uterine cavity due it’s alkalinity

48
Q

Sperms move though uterine cavity and tube by?

A

Peristalsis and cilia

Chemoattractants secreted by corona radiata

49
Q

What binds the sperm to the cell membrane of ovum?

A

Integrins on ovum and disintegrins on the sperms

50
Q

What enzyme initiates acrosomal reaction?

A

ZP3

51
Q

What binds syncytiotrophoblast to the endometrium?

A

Selectins, integrins, fibronectins

52
Q

What gives the sperm tail energy

A

ATP from metabolism of fructose in mitochondria

53
Q

What are the chemoattractants of epiblasts from the primitive streak?

A

Fibroblast growth factor 8

54
Q

Why is the cranial end of a trilaminar embryonic disc bigger?

A

Because cells from primo groove are traveling laterally and then cranially

55
Q

Hypotelorism

A

Eyes are near due to deficiency of central features of the face
Opposite is hypertelorism

56
Q

Holoprosencephaly

A

A defect caused by teratogens (e.g alcohol) due to underdevelopment of the midpoint of developing a trilaminar disc.
It causes hypotelorism, underdeveloped forebrain, fusion of lateral ventricles.

57
Q

Caudal dysgenesis/ sirenomelia

A
Poor development of the caudal region caused by mothers with diabetes mellitus
Leads to:
Underdeveloped/ fused LL
Abnormal dev. vertebra
Renal agenesis (absence)
Genital abnormality
58
Q

Dextrocardiac

A

Hearts on the right

59
Q

Situs invertus

A
Trans location of all the viscera of the thorax and abdomen.
Placed opposite from their normal sites.
20% patients have:
Ciliary sinusitis 
Bronchictasis
Male infertility (sperms with no cilia)
60
Q

Somatomeres that do not form somites

A

1-7

Cranial to otic

61
Q

Somatomeres that form somites

A

Otic to caudal

42 to 44 are formed at end of 5th week

62
Q

Distribution of somites

A
4 occipital 
8 cervical
12 thoracic
5 lumbar
5 sacral
8-10 coccygeal
63
Q

Anomalies due to shape of placenta

A
Bilobed 
Multilobed
Diffuse
Succenturiata
Fenestrata
Circumvellate
64
Q

Placental anomalies due to position of umbilical cord

A

Marginal
Furcate
Velamentous

65
Q

Placental barriers

A
Syncytiotrophoblast
Cytotrophoblast
Basement membrane of CT
Mesoderm
Endothelium of blood vessels
66
Q

Placenta previa

A

When placenta occupies the lower 1/3 of the uterus

1st degree to 4th degree

67
Q

Urachal anomalies

A

Sinus: persists only in the upper half close to UC
Cyst: forms a cyst on its course
Fistula: continuous from UC to the apex of bladder

68
Q

Types of placental barriers

A
Endotheliochorial
Endothelioendothelial
Epitheliochorial
Hemochorial (humans)
Hemoendothelial
69
Q

Contents of umbilical cord

A
2 arteries 
1 left vein
Wharton’s jelly
Remnants of allantois
Remnants of yolk sac or vitellointestinal duct
70
Q

Meckel’s

A

Persistence of yolk sac

71
Q

Size of umbilical cord

A

50-52 cm long

1-2 cm wide

72
Q

Cord prolapse

A

Compression of UC between the head of fetus and the pelvic wall of mother
Others are :
strangulation of neck of fetus
Too short UC causes pull of placenta during parturition

73
Q

Twining

A

Nurturing of two conceptus at the same time

74
Q

Dizygotic or fraternal twins

A
2 ovums fertilized separately 
- different amnion
- different chorion
- placenta may be separate or fused
In fused placenta, there is mixture of blood leading to two red blood cell types
75
Q

Monozygotic or identical

A

1 ovum fertilized to give a
blastocyst with two embryoloblast
-monochorionic diamniotic with one placenta
Sometimes single embryoloblast
splits into 2
- monochorionic monoamniotic with one placenta

76
Q

Erythrocyte mosaicsm

A

When placentas of dizygotic twins fuse and their RBCs becomes of two different types

77
Q

Erythrocyte mosaicsm

A

When placentas of dizygotic twins fuse and their RBCs becomes of two different types

78
Q

What are pharyngeal arches

A

Mesenchymal condensations with ectodermal covering externally and endodermal internally.
There are 1-6 arches
Only 1-4 is visible

79
Q

What are pharyngeal grooves

A

They are clefts formed by the invagination of ectodermal covering of pharyngeal arches.

80
Q

What are pharyngeal pouches

A

They are spaces formed between invagination of endoderm of two pharyngeal arches

81
Q

Skeletal component of maxillary process of 1st pharyngeal arch

A

Maxilla
Premaxilla
Zygomatic
Part of temporal

82
Q

Skeletal component of mandibular process of 1st pharyngeal arch

A

Mandible
Malleus
Meckel’s
Incus
Anterior ligament of malleus
Sphenomandinular ligament

83
Q

Skeletal component of 2nd pharyngeal arch

A

Stapes
Styloid process
Stylohyoid ligament
Lesser horn of hyoid bone
Upper part of hyoid bone

84
Q

Skeletal component of 3rd pharyngeal arch

A

Greater horn of hyoid
Lower part of hyoid

85
Q

Skeletal component of 4th and 6th pharyngeal arch

A

Cricoid
Cuneiform
Corniculate
Arethenoid
Thyroid

86
Q

Muscular component of 1st pharyngeal arch

A

Mylohyoid
Muscles of mastication
Anterior belly of digastric
Tensor tympani
Tensor palatini

87
Q

Muscular component of 2nd pharyngeal arch

A

Stapedius
Stylohyoid muscle
Posterior belly of digastric
Auricular muscle
Muscles of facial expression

88
Q

Muscular component of 3rd pharyngeal arch

A

Stylopharyngeous

89
Q

Muscular component of 4th pharyngeal arch

A

Cricothyrod
Levator palatini
Constrictors of pharynx

90
Q

Muscular component of 6th pharyngeal arch

A

Intrinsic muscles of larynx

91
Q

Nerve supply to 1st pharyngeal arch

A

Mandibular div of trigerminal
(Dermis is by: maxillary, Mandibular and ophthalmic branches)

92
Q

Nerve supply to 2nd pharyngeal arch

A

Facial nerve

93
Q

Nerve supply to 3rd pharyngeal arch

A

Glossopharyngeal nerve

94
Q

Nerve supply to 4th pharyngeal arch

A

Superior laryngeal branch of vagus

95
Q

Nerve supply to 6th pharyngeal arch

A

Recurrent laryngeal branch of vagus

96
Q

Derivatives of 1st pharyngeal pouch

A

Proximal: auditory tube
Distal: middle ear cavity

97
Q

Derivative of 2nd pharyngeal pouch

A

Regresses and gives space for tonsils

98
Q

Derivative of 3rd pharyngeal pouch

A

Dorsal: Inferior parathyroid glands
Ventral: Thymus

99
Q

Derivative of 4th pharyngeal pouch

A

Dorsal: Superior parathyroid glands
Ventral: Ultimobranchial body

100
Q

Derivative of 5th pharyngeal pouch

A

Ultimopharyngeal body

101
Q

What are pharyngeal membranes

A

A connection between the ectoderm and endoderm of pharyngeal apparatus.

102
Q

Derivative of 1st pharyngeal membrane

A

Tympanic membrane

103
Q

Derivative of 1st pharyngeal groove/cleft

A

External auditory meatus

104
Q

Erythrocyte mosaicsm

A

When placentas of dizygotic twins fuse and their RBCs becomes of two different types

105
Q

Other name for spermiogenesis

A

Metamorphosis

106
Q

What are the equivalents of Sertoli cells and interstitial cells of leydig in females

A

Follicular cells and theca cells respectively

107
Q

Stages of PGC development in males

A

PGD
2 dark type A
1 dark & 1 light type A
2 dark type B
Primary spermatocyte
Secondary spermatocyte
Spermatid
Spermatozoa

108
Q

Corpus luteum life span

A

10-12 days if not fertilized
2-3 months if fertilized

109
Q

What aids movement of sperm into ampulla and ovum into ampulla

A

Peristalsis and uterine cilia

110
Q

Capacitation

A

Removal of glycoprotein coat and seminal plasma protein covert acrosomal region of sperms

111
Q

Steps for fertilization

A

Penetration of corona radiata
Pen of ZP
fusion of cell membranes
Completion of 2nd meiotic division
Formation of male pro nuclei
Formation of zygote

112
Q

Artificial stimulation of follicular cell growth is by

A

Administration of gonadotrophins/ clomiphene citrate

113
Q

Major fxn of zona pellucida

A

Prevent implantation at wrong places to prevent ectopic pregnancy