Histology of the Derivatives Pharyngeal Arch Region (Exam 1)

Question 1

Ant. 2/3 (moveable) Dorsal surface has:

Answer 1

SSK epithelium
Ectoderm germ layer
Specialized Mucosa

Question 2

Ant. 2/3 (moveable) Ventral surface has:

Answer 2

SSNK
Endoderm
Lining mucosa

Question 3

Posterior 1/3 (immovable) Dorsal surface:

Answer 3

SSNK
Endoderm (Hypobrachial emmence 3rd/4th PA
Lining mucosa

Question 4

What is specialized Mucosa:

Answer 4

Refers the presence of surface elevations known as lingual papillae– Lingual papillae may contain taste buds

Question 5

The only place where lingual papillae is:

Answer 5

Specialized Mucosa, which is found mainly on the dorsal surface of anterior 2/3 of tongue

Question 6

Skeletal muscle extrinsic and intrinsic tongue muscle is:

Answer 6

Derived occipital somites- Primarily hypoglassal nerve

Question 7

Name the four types of lingual paella in Ant 2/3:

Answer 7

Filiform
Fungiform papillae
Foliate
Circumvallate (vallate)

Question 8

Describe Filiform Papillae

Answer 8

Located: Scattered amount fungiform papilla on dorsal surface of anterior 2/3.
- Conical in shape, extensive keratinization
Innervation (GSA): Branch of Trigeminal V3— Pain and Temp

Question 9

Describe Fungiform papillae:

Answer 9

Contain taste buds (Red vascularized)
Located: scattered over dorsal surface of anterior 2/3 tongue.
Round shape, variable height; highly vascularized CT
Innervation: (SVA); chorda tympani (branch of VII)– Innervation to taste buds

Question 10

Describe Foliate papillae:

Answer 10

Contain taste buds
Located along posterior lateral surface of anterior 2/3
Conical shape, same height, rudimentary in man; associated with serous glands

Question 11

Describe Circumvallate (Vallate):

Answer 11

Contain taste buds
Located: anterior to the sulcus terminals; anterior 2/3 dorsal surface of tongue
Large domed shaped papillae; serous salivary glands (glands of Von Ebner)
Innervation: (SVA) glossopharyngeal (Branch of IX) (3rd arch)

Question 12

Describe taste buds:

Answer 12

Taste buds are chemoreceptive cells associated with most papillae or scattered in the oral Mucosa. Each bud composed of four sensor cell (neuroepithelial) types:
Type I supporting cells
Type II and II neuroepithelial receptor cells
Type IV basal (regenerative): stem cells

Sour, Bitter, Sweet, Salty, Unami
Can be found on: Fungiform, foliate, circumvallate papila

Question 13

What is a taste Pore?

Answer 13

Small opening at the apex of taste bud; Serves as site of sensory transduction. `

Question 14

Features of Ventral Tongue– Ant 2/3

Answer 14

Lining mucosa: SSNK and underlying CT
Lingual papillae absent
Mixed minor salivary glands open onto ventral surface– glands located near tip

Question 15

All taste buds are capable of detecting each test modality due to:

Answer 15

Different sensory receptors

Question 16

Taste buds may also be scattered without papillae in:

Answer 16

Posterior 1/3; Epiglottis, soft palate

Question 17

Describe the Ventral tongue anterior 2/3

Answer 17

Lining mucosa- SSNK and underlying CT
Lingual papillae absent
Mixed minor salivary glands open onto ventral surface– glands located near tip

Question 18

Name the three types of minor salivary glands in tongue:

Answer 18

Serous
Mucous
Mixed

Question 19

Describe Serous salivary glands:

Answer 19

Glands may secrete a watery (serous) secretion and stain very eosinophilic, nuclei are rounded, Known as glands of Von Ebner

• Anterior to sulcus terminalis region of circumvallate papillae, foliate papilla

Question 20

Describe Mucous salivary glands:

Answer 20

Mucous glands may secrete a viscous (mucous) secretion and appear pales staining due to mucin, nuclei flattened at cell base

• Posterior 1/3 of tongue (Also found in soft palate)

Question 21

Describe mixed (seromucous) salivary glands:

Answer 21

Produce a mixed secretion. Serous cell “ sits” on top of mucous cell- Serous cell called serous demilune (SD)

Note* Often the mixed gland may be more serous or produce a predominately mucous type of secretion.

• Anterior 2/3 near tip open onto ventral side; Will look largely mucous. Also on the lavial surface (lip) and buccal surface, pharynx, and larynx

Question 22

Where are the laryngopharynx and larynx:

Answer 22

Both corresponds to region between the epiglottis and cricoid cartilage and is derived from 4th and 6th arch. The larynx sits anterior to laryngopharynx.

Question 23

What is the Pharyngeal (adenoids):

Answer 23

Single structure in the midline of the roof of the nasoparynx

Question 24

What is the Palatine:

Answer 24

Bilateral; posterior to palatoglossal folds in oropharynx

Question 25

What is the lingual:

Answer 25

Midline structure post 1/3 of tongue. SSNK and mucous glands + skeletal Muscle

Question 26

What are tonsils?

Answer 26

Tonsils are groups of lymphatic nodules covered with epithelium. The epithelium varies based on the location of the tonsils

Question 27

What is the pharyngeal tonsil?

Answer 27

Covered with PSCC and SSNK (Majority of PSCC)

Question 28

What is the Palatine tonsil?

Answer 28

Covered with SSNK; deep crypts

Question 29

What is the lingual tonsil?

Answer 29

Covered with SSNK; Mucous salivary glands in submucosa layer

Question 30

What is the Embryonic origin of the Pharyngeal tonsil?

Answer 30

• Roof of nasopharynx in the region of PA 1.
• Epithelium: Endoderm of nasopharynx: PSCC and SSNK
• WBC of Lymph nod: Lateral plate
• CT- Ectomesenchyme

Question 31

What is the Embryonic origin of the Palatine Tonsil:

Answer 31

Epithelium: Endoderm of 2nd pouch: SSNK
WBC of nodule: Lateral Plate
CT: Ectomesenchyme of PA2

Question 32

What is the Embryonic origin of the Lingual tonsil:

Answer 32

Floor of 3rd Arch (hypobranchial eminence)
(Not pouch derivative since midline structure)
- Epithelium: Endoderm of posterior 1/3: SSNK
- WBC of nodule: Lateral Plate from bone marrow cells
- CT: Ectomesenchyme of PA 3

Question 33

What is the function of tonsils:

Answer 33

Immune function (MALT): Site of antibody-mediated (humoral) immune response