Embryology

Question 1

Tissues formed from mesoderm

Answer 1

Muscle
Cardiac muscle
Kidney
Bone
Cartilage
Adipose
Circulatory system
Lymphatics
Dermis
Dentine of teeth
GU system
Testes
Serous membranes
Spleen
Notochord

Question 2

Tissues formed from ectoderm

Answer 2

The surface ectoderm develops into: epidermis, hair, nails, lens of the eye, sebaceous glands, cornea, tooth enamel, the epithelium of the mouth and nose.
Note: The anterior pituitary develops from the ectodermal tissue of Rathke’s pouch.

The neural crest of the ectoderm develops into: peripheral nervous system, adrenal medulla, melanocytes, facial cartilage.

The neural tube of the ectoderm develops into: brain, spinal cord, posterior pituitary, motor neurons, retina.

Question 3

Tissues formed from endoderm

Answer 3

Pharynx
Oesophagus
Stomach
SI
Colon
Liver
Pancreas
Bladder

Epithelial trachea and bronco

Lungs - develop from GI tract
Thyroid
Parathyroid

Question 4

Development of CV system

Answer 4

3rd week- formation of the primitive heart tube
Angiogenic cells
Suspended in pericardial membrane
From superior to inferior, the primitive heart tube is comprised of six regions:
Aortic roots (Arterial poles)
Truncus arteriosus
Bulbus cordis- ventricles
Ventricle
Atrium
Sinus venosus (Venous poles)

Bulbus cordis moves- ventrally, caudally and right
Ventricles- move dorsally, cranially and left

First organ in embryo beginning to function - beating in 4th week

Septum primium forms in 4th week

Question 5

What does sinus venous form

Answer 5

Atrium and Coronary sinus

Question 6

What does the bulbs cordis form

Answer 6

Aortic vestibule of left ventricle

Question 7

Formation of fossa oval

Answer 7

Fusion of septum primum and secundum

Question 8

Location of fossa ovals

Answer 8

Posteromedial wall

Question 9

What does urethra develop from

Answer 9

Cloaca

Question 10

What ducts give male vs female

Answer 10

Wollfian (mesonephric)- male
Connect primitive kidney to cloaca under testosterone

Mullerian - female

Question 11

Cause of cleft lip

Answer 11

Incomplete fusion between medial nasal process and maxillary

Question 12

Cause of cleft palate

Answer 12

Failure of fusion between palatine process

Question 13

Migration of test phases

Answer 13

1st- abdo to internal ring - gubernaculum thickens and shortens anchoring

2nd to scrotum - gubernaculum responds to testosterone - grows migrating through canal

Question 14

What does the allantois become

Answer 14

Evagination of handout and becomes urachus

Question 15

What forms the uterus

Answer 15

Mullerian duct

Along with fallopian, cervic, upper vagina

Question 16

When does gender differentiation occur

Answer 16

Week 8- fully differentiated by 9

Start producing testosterone

Question 17

What is anencephaly and when does it occur

Answer 17

Failure of cranial neuropore to close around day 25

Question 18

What forms round ligament

Answer 18

Gubernaculum with is from mesoderm

Question 19

What tissue origin are the gonads from

Answer 19

Mesoderm

Question 20

What condition is associated with myelomeningocele

Answer 20

Chiari type 2

Question 21

Mx of imperforate anus

Answer 21

Sigmoid colostomy then definite repair after 3-6m

Question 22

Which arch does ductus arteriosus form from

Answer 22

6th

Question 23

Teenager, well developed breasts and hair, but absence of uterus

Answer 23

Mullerian agenesis

Question 24

Androgen insensitivity syndrome

Answer 24

X linked

Female genetali
Testes- produce Mullerian inhibiting so no uterus, and Fallopian tubes

If mild- male genetali

Question 25

When does palate fully form

Answer 25

10w

Question 26

When does ear form

Answer 26

8w

Question 27

What makes intubating children more difficult

Answer 27

Larger head Larger tongue Cephalic larynx Shorter trachea

Question 28

What is hypospadias linked with

Answer 28

Undescended teste Cleft lip/palate Congenital heat Inguinal hernia

Question 29

% of children not born with fusion of L5/S1 and what they develop

Answer 29

10-15% Spina bifida occulta

Question 30

Continuous murmur infraclavicular

Answer 30

PDA

Question 31

Which structure prevents the ascent of hors how kidney

Answer 31

IMA

Question 32

When do kidneys develop

Answer 32

6-8w

Question 33

Partial fusion of Mullerian ducts causes

Answer 33

Bicornate uterus

Question 34

Cyanotic feet but normal hands

Answer 34

PDA with shunt reversal As subclavian receives normal O2

Question 35

External male genitali development depends on

Answer 35

DHT

Question 36

What happens to foreamen oval at birth

Answer 36

Elevated LA pressure forces septum priumum and secundum together closing it

Question 37

Where subarachnoid space finishes

Answer 37

S1-3 Hilum terminale continues with Pia mater

Question 38

Where are vas deferens and prostate developed from

Answer 38

VD- mesonephric Psostate- ueogenital

Question 39

When does PDA fully close

Answer 39

2-3 w Narrows after 12hr

Question 40

Movement of hindgut on its mesocolon in development

Answer 40

Hinges to the left

Question 41

Incomplete endocardial cushion fusion defect

Answer 41

AV septal defect

Question 42

What is associated with oesophageal fistula

Answer 42

Polyhydraminos

Question 43

What is the embryological equivalent of Batholin glands in men

Answer 43

Bulbourethral - Skenes

Question 44

When should intervention be considered in undescended teste

Answer 44

6-12m

Question 45

Which arch is styloid process derived

Answer 45

2nd

Question 46

Which arch is palatine tonsil derived

Answer 46

2nd

Question 47

Which arch is the maxilla, zygomatic bone, palatine bone from

Answer 47

1st

Question 48

Which arch is mallet incus, mockers cartilage and sphenomandibular from

Answer 48

1st