Embryo

Question 1

1st aortic arch derivative:

Answer 1

part of maxillary artery

Question 2

1st branchial cleft derivative:

Answer 2

external auditory meatus

Question 3

1st branchial arch derivative:

Answer 3

Meckel Cartilage: mandible, malleus, incus, spheno-mandibular lig Muscles of mastication (temporalis, masseter, lat/med pterygoids), mylohyoid, ant belly digastric, tensor tympani, tensor veli palatini CN V2 and V3

Question 4

1st branchial pouch derivative:

Answer 4

Middle ear cavity, eustachian tube, mastoid air cells

Question 5

2nd aortic arch derivative:

Answer 5

Stapedial artery and hyoid artery

Question 6

2nd-4th branchial clefts:

Answer 6

temporary cervical sinuses, obliterated by prolif of 2nd arch mesenchyme

Question 7

2nd branchial arch derivative:

Answer 7

Reichert cartilage: stapes, styloid process, lesser horn hyoid, stylohyoid lig Muscles of facial expression, stapedius, stylohyoid, platysma, post belly digastric CN VII

Question 8

2nd branchial pouch derivative:

Answer 8

Epithelial lining of palatine tonsil

Question 9

3rd aortic arch derivative:

Answer 9

Common carotid and prox part of internal carotid artery

Question 10

3rd branchial arch derivative:

Answer 10

Cartilage: greater horn of hyoid Stylopharyngeus mm CN IX

Question 11

3rd branchial pouch derivative:

Answer 11

Dorsal wings: inferior parathyroids Ventral wings: thymus ***End up BELOW 4th pouch structures

Question 12

4th aortic arch derivative:

Answer 12

Left: aortic arch Right: prox part of right subclavian art

Question 13

4th-6th branchial arch derivatives:

Answer 13

Cartilage: thyroid, cricoid, arytenoids, corniculate, cuneiform 4th arch: pharyngeal constrictors, cricothyroid, levator veli palatini, CN X superior laryngeal n. 6th arch: intrinsic mm of larynx except cricothyroid, CN X recurrent laryngeal n.

Question 14

4th branchial pouch derivative:

Answer 14

Dorsal wings: superior parathyroids

Question 15

6th aortic arch derivative:

Answer 15

Proximal part of pulmonary arteries, L side: ductus arteriosus

Question 16

Paramesonephric ducts form what?

Answer 16

Fuse to form uterine tubes, uterus, cervix, upper 1/3 vagina Male: involute

Question 17

Mesonephric ducts form what?

Answer 17

Male: epididymis, ductus deferens, seminal vesicles, ejaculatory ducts Female: Gartner’s ducts

Question 18

Bicornuate Uterus due to failure of?

Answer 18

Fusion of paramesonephric ducts

Question 19

Non-fusion of urethral folds causes:

Answer 19

Hypospadias (M), fuse to form ventral aspect of penis Vestibule of vagina (F)

Question 20

Faulty positioning of the genital tubercle causes:

Answer 20

Epispadias (opening on dorsal surface of penis)

Question 21

Common Cardinal Veins develop into what?

Answer 21

SVC and other veins of the systemic venous circulation

Question 22

Vitelline veins form what?

Answer 22

Veins of the portal system

Question 23

Umbilical veins form what?

Answer 23

Degenerate

Question 24

Truncus arteriosus develops into what?

Answer 24

Ascending aorta, pulmonary trunk Neural crest cell migration partitions it into the two arteries by causing fusion and twisting of the truncal and bulbar ridges Failure results in transposition of great vessels/ToF

Question 25

Bulbus cordis gives rise to:

Answer 25

Smooth parts (outflow track) of L and R V

Question 26

Primitive atria give rise to:

Answer 26

Trabeculated part of L and R A

Question 27

Primitive ventricle gives rise to:

Answer 27

Trabeculated part of L and R V

Question 28

Primitive pulmonary vein gives rise to:

Answer 28

Smooth part of LA

Question 29

Left horn of sinus venosus gives rise to:

Answer 29

Coronary sinus

Question 30

Right horn of sinus venosus gives rise to:

Answer 30

Smooth part of RA (sinus venosum)

Question 31

SVC develops from:

Answer 31

R common cardinal vein and R anterior cardinal vein