Week 2 Chpt. 24 Tongue

Question 1

How far in utero does the tongue develop

Answer 1

• At about 4½ weeks in utero the tongue starts to develop as a swelling that arises out of the back of the pharyngeal arches
( 1st arch-mandibular)
. This swelling develops from the future floor of the mouth

Question 2

4.5 weeks utero

Question 3

Tongue Muscles
2 groupings?
Is it voluntary or involuntary?

Answer 3

• The muscles of the tongue are controlled willfully and are referred to as skeletal muscle or voluntary striated muscle
• They are divided into 2 groupings:
• 1. intrinsic muscles
• 2. extrinsic muscles

Question 4

Tongue is covered with?

Answer 4

• The tongue is covered with stratified squamous epithelium:
*dorsal (upper) surface - thick epithelium (parakeratinized - keratinized)
*ventral (lower) surface - thin epithelium

Question 5

Scattered throughout the dorsum are 4 types of elevated structures known as papillae?

Answer 5

Contains 4 types of papillae:
1. circumvallate (vallate)
2. fungiform
3. filiform
4. foliate

Question 6

Tongue pic

Answer 6

Question 7

Circumvallate (vallate) Papillae:

Answer 7

• Circumvallate (vallate) Papillae:
- Around 13 elevations (V)
- V-shaped row facing posteriorly of circular raised elevations
- Divides Posterior 1/3 and ant 2/3
- Under a microscope, they rest in troughs
- Many taste buds around lateral surface
- Small salivary glands lie beneath papillae wash them clean (glands of Von Ebner)

Question 8

Fungiform Papillae

Answer 8

Anterior 2/3 of tongue,
Tiny, round, red, raised, spots
- Taste buds in these papillae
Only on upper portion of tongue NOT side (whats side of tongue called?)
- In younger children they appear redder

Question 9

Filiform Papillae

Answer 9

• Remainder anterior 2/3 of tongue
• Slender, threadlike, pointed projections
• No taste buds
  -Tactile sensation (know something is there) (cat)
  • Epithelia on these papillae may grow very long, known as hairy tongue
  • If the epithelia are lost, the surface becomes very smooth and is referred to as glossitis. (Vit deficiency)

Question 10

Foliate Papillae:

Answer 10

• If you grab the tip of the tongue with a piece of gauze and pull it out and to the side, you will see a roughened surface
• Posterior 1/3 of tongue and on lateral (side) surfaces, close to vallate papillae
• Few taste buds, not well developed (*area where oral cancer can begin) hard to see this area with folds of tissue

Question 11

Lingual Tonsils

Answer 11

• The region near the midline on the dorsum, just behind the circumvallate papillae at the base of tongue, is known as the lingual tonsils
• Lymphoid tissue (similar to palatine tonsil) provides defense mechanism for infection.
  lingual tonsils will become reddened and enlarged during episodes of infection