Embryology

Question 1

Embryology Introduction

Twins (Mono, Di, Conjoined)

Answer 1

Mono: 1 oocyte
Di: 2 oocyte/ 2 sperm
Conjoined: Inner cells never seperate

Question 2

Embryology of Nerves and Muscle

Dermatome

Answer 2

Dermis of the back

Question 3

Development of Back

Wnt Pthwy

Answer 3

Transcription Factor
Ventral - Dorsal

Question 4

Development of Back

Phocomelia

Answer 4

Absent of long bones, hand and feet w/trunk

Question 5

Development of Back

ZPA

Answer 5

SHH
Anterior - posterior

Question 6

Embryology Introduction

Embryology Week 1-2

Answer 6

Zygote –> Cleavage (2-16) –> Morula –> Blastocyte (32) –> Implantation in lining of the uterus

Question 7

Embryology Introduction

Pharyngeal Arches

Answer 7

Forms Head & Neck
NC cells around foregut
6 –> 5 arches

Question 8

Development of Back

Paraxial - Somatic

Answer 8

Appendicular Skeleton + skin outside back

Question 9

Development of Back

Polydactyly

Answer 9

Many digits

Question 10

Embryology Introduction

Embryology Week 9-38

Answer 10

Fetal Growth

Question 11

Embryology Introduction

Embryoblast

Answer 11

Inner Cells
Epiblast (amniotic)
Hypoblast (Yolk Sac)
Embryo Proper

Question 12

Embryology Introduction

Umbilical Cord

Answer 12

Allantois (waste), connecting stalk, vitelline duct

Question 13

Development of Back

PCD in limbs

Answer 13

AER leads to apoptosis to remove webbing + smaller AER

Question 14

Development of Back

Paraxial - Sclerotome

Answer 14

Surrounds NT cells + Notochord –> spinal cord formation

Annulus Fibrosus

Question 15

Embryology Introduction

Mesoderm

Answer 15

Paraxial (Somite –> Sclero/Myo/Derma)
Intermediate (Urogential Organs - kidney/ureter)
Lateral (Somatic, Splanhic)

Question 16

Development of Back

Amniotic Bands

Answer 16

Amputation of limbs

Question 17

Development of Back

Brachydactyly

Answer 17

Shortened limbs

Question 18

Embryology Introduction

Embryology Week 3-8

Answer 18

Gastrulation (bi –> trilameter), Neurulation (forming of neural cord),

Question 19

Embryology of Muscle and Nerves

Sclerotome

Answer 19

most of the axial skeleton, split into cranial and caudal portion and form with the one above so the sensory portions can go through this layer to get to dermatome and myotome

Question 20

Embryology Introduction

Ectoderm

Answer 20

Surface (skin/appendgies)
Neuro (Crest - PNS, Tube - CNS)

Question 21

Development of Back

Cleft Floot

Answer 21

Extreme of syndactyly

Question 22

Embryology Introduction

Zona Pellucida

Answer 22

Attracts sperm + prevents ectopic pregnancy

Question 23

Development of Back

Paraxial - Notochord

Answer 23

Nucleus Pulposis

Question 24

Development of Back

AER

Answer 24

FGF8 (limb growth)
proximal-distal

Question 25

# Embryology Introduction Primitive Streak

Answer 25

Linear band of thick epiblast on caudal end (growing cranially) forming the primitive knot

Question 26

# Embryology Introduction Trophoblast

Answer 26

Outer Cells Cytotrophoblast (Embryo in uterus) SyncytioTrophoblast (>2 Cyto) Placenta

Question 27

# Embryology Introduction Endoderm

Answer 27

GI Tract lining, urinary respiratory

Question 28

# Development of Back Syndactyly

Answer 28

Fused Digits

Question 29

# Development of Back Duplicated AER

Answer 29

2 AER

Question 30

# Embryology Introduction Teratoma

Answer 30

Contains immature or fully formed tissues - hair/teeth

Question 31

# Embryology of Nerves and Muscles Myotome

Answer 31

Skeletal Muscle Epimere - intrinsic Hypomere - trunk and limb preaxial (flexors anterior) Postaxial (extensor posterior)

Question 32

# Development of Back Paraxial - Ventral/Hypaxial

Answer 32

Skeletal musculature of the ventrolateral wall and limbs

Question 33

# Development of Back Club Foot

Answer 33

Walking on ankles Insufficient amniotic fluid (oligohydramnios)

Question 34

# Embryology Introduction Sacrococcygeal Teratoma

Answer 34

High pluripotent epiblast cells of primitive streak

Question 35

# Development of Back Paraxial - Dorsal/epaxial

Answer 35

Intrinsic Back

Question 36

# Development of Back Resegmentation

Answer 36

Intersegmental Vertebrae

Question 37

# Embryology Introduction Amniotic Cavity w/Definitive Yolk Sac in folded embryo

Answer 37

Definitive yolk sac pushes away primary yolk sac

Question 38

# Development of Back Amelia

Answer 38

Missing Limbs