embryology of respiratory

Question 1

Pharygeal Appartus

Question 2

During which weeks of intrauterine life does six pharyngeal appartus develop?

Answer 2

4th and 5th weel

Question 3

What does the pharyngeal appartus contain

Answer 3

• pharyngeal arches
• mesenchyme
• pharyngeal pouchs
• pharyngeal clefts

Question 4

Each pharyngeal arch consist of?

Answer 4

1. a core of mesenchymal tissue
2. covered on the outside by surface ectoderm and

– on the inside by endoderm—yolk sac origin

1. neural crest cells migrate into the ph. arches to for the development of the skeletal components.
2. original mesoderm of the arch gives rise to the musculature
3. – pharyngeal arch artery - from the corresponding aortic arch
4. a cranial nerve.

Question 5

III Arch contains which nerve?

Answer 5

Glossopharyngeal nerve

Question 6

IV Arch contains which nerve?

Answer 6

External laryngeal

Question 7

I Arch contains which nerve?

Answer 7

maxillary and mandibular nerves

Question 8

VI Arch contains which nerve?

Answer 8

Recurrent laryngeal nerve

Question 9

The aortic sac gives of pharyngeal arch arteries?

Answer 9

Question 10

What is the derivatives of I arch?

Answer 10

1. Skeletal element – Premaxilla, maxilla, part of temporal bone, mandible, malleus, incus, anterior ligament of the malleus & sphenomandibular ligament
2. Muscles–tensor tympani, tensor veli palatini, muscles of mastication, anterior belly of digastric & mylohyoid

Question 11

II Arch derivatives?

Answer 11

1. Skeletal – stapes, styloid process, stylohyoid ligament, lesser horn & superior rim of the body of hyoid bone

Muscles – stapedius, stylohyoid, posterior belly of digastric, muscles of facial expression.

Question 12

III ARCH derivatives?

Answer 12

1. Skeletal – stapes, styloid process, stylohyoid ligament, lesser horn & superior rim of the body of hyoid bone
2. Muscles – stapedius, stylohyoid, posterior belly of digastric, muscles of facial expression

Question 13

Hypopharyngeal eminence is formed from which arches?

Answer 13

2nd , 3rd , 4th arches

Question 14

IV ARCH derivatives

Answer 14

Skeletal element –Epiglottis & cuneiform,thyroid, crycoid,arytenoid, corniculate cartilages

Muscles– cricothyroid, levator veli palatini and constrictors of the pharynx

Question 15

VI Arch derivatives?

Answer 15

Skeletal element – Arytenoid, corniculate, and cricoid cartilages

Musculature -Intrinsic muscles of larynx.

Question 16

Which Arch is recessed?

Answer 16

V

Question 17

Where does the thyroid gland migrate from?

Answer 17

The thyroid gland originates in the midline at the level of the foramen cecum and descends to the level of the first tracheal rings.

Question 18

Frontonasal processes are derived from?

Answer 18

mesenchyme ventral to brain vesicle.

Question 19

nasal placodes is derived from

Answer 19

ectoderm inductive influence of vental forebrain.