Aortic Arch derivatives

Question 1

Artery of 1st aortic arch

Answer 1

Maxillary artery (branch of external carotid)

Question 2

Artery of 2nd aortic arch

Answer 2

Stapedial artery and hyoid artery

Question 3

Artery of 3rd aortic arch

Answer 3

Common Carotid artery and proximal part of internal Carotid artery

Question 4

Artery of 4th aortic arch

Answer 4

Left - aortic arch

Right - proximal part of right subclavian artery

Question 5

Artery of 6th aortic arch

Answer 5

Proximal part of pulmonary arteries and (on LEFT) ductus arteriosus

Question 6

a. What are branchial clefts derived from?
b. Branchial arches?
c. Branchial pouches?

Answer 6

a. Ectoderm
b. Mesoderm and neural crest
c. endoderm

Question 7

What does 1st branchial cleft become?

Answer 7

External auditory meatus

Question 8

What do 2nd through 4th branchial clefts become?

Answer 8

Form temporary cervical sinuses –> obliterated by proliferation of 2nd arch mesenchyme

Question 9

Cause of branchial cleft cyst within lateral neck

Answer 9

Persistent cervical sinus (2nd-4th clefts)

Question 10

Nerve of 1st branchial arch

Answer 10

CN V2 and V3 (chew)

Question 11

Nerve of 2nd branchial arch

Answer 11

CN VII (Facial expression) (smile)

Question 12

Nerve of 3rd branchial arch

Answer 12

CN IX (Stylo-pharyngeus) (think swallow styl-ishly)

Question 13

Nerve of 4th branchial arch

Answer 13

CN X (superior laryngeal branch) - swallow

Question 14

Nerve of 6th branchial arch

Answer 14

CN X (recurrent laryngeal branch) - speak

Question 15

Muscles of 1st arch

Answer 15

Muscles of mastication (temporalis, masseter, lateral and medial pterygoids), Mylohyoid, anterior belly of digastric tensor tympani, tensor veli palatini

Question 16

Muscles of 2nd arch

Answer 16

Muscles of facial expression; Stapedius, Stylohyoid, PlatySma, posterior belly of digastric

Question 17

Muscles of 3rd arch

Answer 17

Stylopharyngeus (think stylopharyngeus innervated by glossopharyngeal)

Question 18

Muscles of 4th arch

Answer 18

Most pharyngeal constrictors; cricothyroid; levator veli palatini

Question 19

Muscles of 6th arch

Answer 19

ALL intrinsic muscles of larynx EXCEPT cricothyroid

Question 20

Cartilage of 1st arch

Answer 20

Meckel cartilage
Mandible
Malleus, Incus
Spheno-Mandibular ligament

Question 21

Cartilage of 2nd arch

Answer 21

Reichert cartilage: Stapes, Styloid process, lesser horn of hyoid, Stylohyoid ligament

Question 22

Cartilage of 3rd arch

Answer 22

Greater horn of hyoid

Question 23

Cartilage of 4th and 6th arch

Answer 23

Thyroid, cricoid, arytenoids, corniculate, cuneiform

Question 24

1st pouch derivatives

Answer 24

Middle ear cavity, eustachian tube, mastoid air cells

Question 25

2nd pouch derivatives

Answer 25

Epithelial lining of palatine tonsil

Question 26

3rd pouch derivatives

Answer 26

Dorsal wings - inferior parathyroids | Ventral wings - thymus

Question 27

4th pouch derivatives

Answer 27

Dorsal wings - superior parathyroids

Question 28

Mutation in germline RET (neural crest cells)

Answer 28

MEN2A --> pheochromocytoma, parathyroid tumor, medullary thyroid cancer

Question 29

Failure of fusion of maxillary and medial nasal processes

Answer 29

cleft lip (formation of primary palate)

Question 30

Failure of fusion of 2 lateral palatine processes or failure of fusion of lateral palatine processes with nasal septum and/or median palatine process

Answer 30

cleft palate

Question 31

a. Paramesonephric duct becomes... | b. Mesonephric duct becomes...

Answer 31

a. Mullerian duct = female genitalia | b. Wolffian duct = male genitalia

Question 32

Which cells secrete Mullein Inhibitory factor?

Answer 32

Sertoli cells

Question 33

What does paramesonephric duct develop into?

Answer 33

Fallopian tubes, uterus, UPPER portion of vagina, lower portion of urogenital sinus

Question 34

Primary amenorrhea in female with fully developed secondary sexual characteristics (functional ovaries)

Answer 34

Mullerian agenesis (no uterus)

Question 35

What does mesonephric duct become? (SEED)

Answer 35

Seminal vesicle Epididymis Ejaculatory duct Ductus deferens

Question 36

Gartner duct

Answer 36

Remnant of mesonephric duct in females

Question 37

What forms male external genital and prostate?

Answer 37

DHT

Question 38

Male internal genitalia | Ambiguous external genitalia until puberty

Answer 38

5 alpha reductase deficiency (testosterone levels increased at puberty)

Question 39

Male and female internal genitalia | Male external genitalia

Answer 39

No sertoli cells or lack of mullerian inhibitory factor

Question 40

Bicornuate uterus

Answer 40

Incomplete fusion of Mullerian ducts

Question 41

Uterus didelphys

Answer 41

Complete failure of fusion --> double uterus, vagina and cervix