Developmental Bio

Question 1

How many pharyngeal/branchial arches are in the developing embryo?

Answer 1

6

Question 2

Which pharyngeal arches contribute to adult structures?

Answer 2

1, 2, 3, 4, 6

Question 3

Which embryologic structure contributes to muscular and vascular elements?

Answer 3

Mesoderm

Question 4

Which embryologic structure forms bony and cartilagenous structures of pharyngeal arches?

Answer 4

Neural crest cells

Question 5

What is the nerve associated with 1st pharyngeal arch?

Answer 5

5

Question 6

What are the bony derivatives of 1st pharyngeal arch

Answer 6

zygoma, maxilla, mandible, incus, malleus

Question 7

What are the muscular derivatives of 1st pharyngeal arch?

Answer 7

Muscles of mastication (temporalis, masseter, etc)

Question 8

What is the nerve affiliated with 2nd pharyngeal arch?

Answer 8

Facial, 7

Question 9

Bony derivatives of second pharyngeal arch

Answer 9

Styloid process of temporal bone, lesser horn of hyoid, stapes

Question 10

Muscular derivatives of 2nd arch

Answer 10

muscles of facial expression

Question 11

What is Treacher-Collins syndrome?

Answer 11

Abnormal development of 1st and 2nd pharyngeal arches

Question 12

Bony derivatives of 4th and 6th arches

Answer 12

Cartilagenous structures of larynx (cricoid and thyroid cartilages)

Question 13

Nerve derived from 3rd arch

Answer 13

Glossopharyngeal (9)

Question 14

Nerve associated with 4th and 6th arches

Answer 14

Vagus (10)

Question 15

Dysfunction of vagus nerve results in

Answer 15

laryngeal and pharyngeal paralysis and autonomic dysfunction (esophageal motility, gastric acid secretion, heart rate variability)

Question 16

Which blood test checks for neural tube defects

Answer 16

AFP and ACh levels

Question 17

Which blood test checks for erythroblastosis fetalis?

Answer 17

Amniotic bilirubin levels

Question 18

Fetal adrenal dysfunction can be detected via

Answer 18

17-hydroxyprogesterone levels, gene linkage analysis involving HLA on chromosome 6

Question 19

Why are pts with CF likely to present with hyponatremia?

Answer 19

They cannot reabsorb sodium through their sweat glands, so excess sodium is lost through sweat (especially on hot summer days)

Question 20

Which electrolyte abnormalities are common in pts with CF?

Answer 20

Hypochloremia and Hyponatremia

Question 21

The bulbis cordis forms which structures?

Answer 21

Smooth portions of left and right ventricles

Question 22

From which structure is the ductus arteriosus derived?

Answer 22

6th embryonic aortic arch

Question 23

Which structure is derived from the first aortic arch?

Answer 23

Part of maxillary artery

Question 24

Which two structures are derived from second aortic arch?

Answer 24

Hyoid artery and stapedial artery

Question 25

Which structures are derived from third aortic arch

Answer 25

Common carotid and proximal internal carotid arteries

Question 26

Which structures are derived from fourth aortic arch?

Answer 26

Left–>aortic arch; Right–> proximal right subclavian

Question 27

Which structures are derived from sixth aortic arch?

Answer 27

Proximal pulmonary arteries and ductus arteriosus