Chapter 3

Question 1

The oropharynx is composed of…

Answer 1

primitive oral cavity and the area of foregut called the pharynx

Question 2

The oral pit first appears when?

Answer 2

4th week of development

Question 3

The pharyngeal arches are so termed because?

Answer 3

they bend around the sides of the pharynx as bars of tissue

Question 4

Within the pharynx grooves called _______ separate each arch

Answer 4

Pharyngeal pouches

Question 5

What does the second hyoid arch form?

Answer 5

facial muscles vessels and hyoid bone

Question 6

The outer surface of each arch is covered with?

Answer 6

ectoderm

Question 7

What will the ectoderm become?

Answer 7

Epithelial lining of oral cavity

Question 8

What does the first pharyngeal groove deepen to become?

Answer 8

external auditory canal leading to the middle ear

Question 9

True or False

After the 5th week no other pharyngeal grooves are seen externally, as the tissues of the 2nd and 5th arch grow over the other arches/grooves to make contact with each other.

Answer 9

True

Question 10

What does the second pharyngeal pouch become?

Answer 10

palatine tonsils

Question 11

What does the third pharyngeal pouch become?

Answer 11

inferior parathyroids/thymus

Question 12

What does the fourth pharyngeal pouch become?

Answer 12

superior parathyroids

Question 13

What does the fifth pharyngeal pouch become?

Answer 13

ultimobranchial body (gives rise to the parafollicular cells of thyroid which produce hormone calcitonin)

Question 14

What do the parafollicular cells of the thyroid produce?

Answer 14

Produce hormone calcitonin

Question 15

The palatine tonsils function in the development of ______

Answer 15

lymphocytes (important for immunology)

Question 16

What do the parathyroid glands regulate?

Answer 16

Calcium

Question 17

What does the thymus produce?

Answer 17

t-cells (destroy invading microbes)

Question 18

What does the ultimobranchial fuse with to contribute to parafollicular cells?

Answer 18

Thyroid

Question 19

When do the first and second aortic arch begin to develop?

Answer 19

4th week and disappear in the 5th week (third arch vessel takes over the facial area of the first two)

Question 20

What do the third arch vessels become?

Answer 20

common carotid arteries (supply face, neck and brain)

Question 21

What do the fourth arch vessels become?

Answer 21

dorsal aorta (supplies blood to remainder of body)

Question 22

What do the vessels of the sixth arch supply

Answer 22

supply lungs with pulmonary circulation

Question 23

After seven weeks the circulation to the face and neck shifts from the internal carotid artery to ___________

Answer 23

the external carotid (internal carotid continues to supply the growing brain)

Question 24

What do the initial skeleton of the pharyngeal arches develop as?

Answer 24

cartilaginous bars

Question 25

Which three bilateral cartilages later transform into bone and function as the middle ear/hearing bone?

Answer 25

malleous stapes incus

Question 26

What is the initial TMJ during the first 20 weeks?

Answer 26

contact point of malleous and incus is the articulation of the lower jaw for the first 20 weeks

Question 27

What is the rod shaped cartilage of the 2nd/hyoid arch known as?

Answer 27

Reichert cartilage

Question 28

What arises from the second arch?

Answer 28

stapes, styloid process, lesser horn, and upper body of the hyoid

Question 29

What does the third arch form?

Answer 29

the greater horn/lower part of hyoid body

Question 30

The fourth arch contributes to hyoid cartilage which then supports what?

Answer 30

thyroid gland

Question 31

What does the 6th arch cartilage form?

Answer 31

laryngeal cartilage

Question 32

What does meckl's cartilage become?

Answer 32

mandible

Question 33

True or False The cartilage articulations exist between the ethmoid and sphenoid and occipital bones in the midline during the period of cranial facial growth

Answer 33

True (ethmosphenoid, sphenooccipital articulations)

Question 34

What are sutures?

Answer 34

Fibrous joints in which opposing surfaces are closely united