GI Histo I

Question 1

What type of cell is responsible for forming dentin matrix?

Answer 1

odontoblasts

Question 2

What is Tome’s dentinal fibers? and what cells form this?

Answer 2

Formed by odontoblasts. Tome’s dentinal fibers are cytoplasmic extensions of the odontoblasts continuing through the predentin and dentinal layers to the dentin-enamel junction

Question 3

What percentage of dentin matrix is organic? and how is this compared to bone?

Answer 3

dentin matrix is 20% organic and is mostely collagen Type I. This is compared to bone of 35% organic

Question 4

What cell type forms the enamel?

Answer 4

Ameloblasts form enamel which covers only the tooth crown

Question 5

What is the composition of enamel?

Answer 5

96% inorganic salts
90% calcium phosphate in form of apatite crystals
4% organic matter and water

Question 6

What causes increment lines of Retzius?

Answer 6

periods of rhythmic growht

Question 7

What are the components of the pulp?

Answer 7

fibroblasts, macrophages, peripheral odontoblats, reticular fibers, nerve fibers, and blood vessels. They enter the tooth via the apical foramen.

Question 8

What type of cell is cementum formed from?

Answer 8

cells of the dental sac differentiate into cementoblasts which deposit cementum on the dentin of the root from neck of tooth to the apex.

Question 9

What are the components of the periodontal membrane?

Answer 9

fibroblasts, osteoblasts, cementoblasts, collagen fibers, blood vessels, and nerve fibers.

Question 10

What is the function of the periodontal membrane of the tooth?

Answer 10

binds cementum to bony socket and limits movement. Absorbs pressures of mastication and prevents this pressure from damaging alveolar bone. The tissue is also highly metabolically active.

Question 11

What structure is most effected by diabetes and scurvy?

Answer 11

periodontal membrane.

Question 12

What is the tongue composed of?

Answer 12

skeletal muscle and glands makes up core of tongue and is covered by mucous membrane

Question 13

What structure separates the anterior 2/3 of the tongue from the posterior 1/3 of the tongue?

Answer 13

sulcus terminalis

Question 14

What is the name of projections on the oral portion of the tongue?

Answer 14

lingual papillae

Question 15

What are the 4 papillae that make up the lingual papillae?

Answer 15

filiform papillae
fungiform papillae
foliate papillae
circumvallate papillae

Question 16

What specific lingual papillae is rudimentary in humans but well developing in lower animals?

Answer 16

foliate papillae

Question 17

What specific lingual papillae is located along the sulcus terminalis surrounded by a moat and contains taste buds on the lateral walls?

Answer 17

circumvallate papillae

Question 18

What specific lingual papillae is the most numerous, evenly distributed in oral upper portion, conical in appearance, and lack taste buds?

Answer 18

filiform papillae

Question 19

What specific lingual papillae are relatively few in number, interspersed singly between rows of filiform papillae, have mushroom appearance, and contain taste buds?

Answer 19

Fungiform papillae

Question 20

What cells, derived from a single stem cell, make up the taste buds?

Answer 20

sustentacular cells

taste cells

Question 21

What cells are involved in tooth development?

Answer 21

odontoblasts
ameloblasts
pulp
cementum
periodontal membrane

Question 22

What are the four layers of the digestive tube?

Answer 22

mucosa (innermost)
submucosa
muscularis externa
outermost layer: serosa and adventitia

Question 23

What are the 3 components of the digestive tube mucosa?

Answer 23

epithelium
lamina propria
muscularis mucosa

Question 24

What layer of the digestive tube includes the Meissner’s plexus?

Answer 24

The submucosa of the digestive tube includes the meissner’s plexus (submucosal plexus)

Question 25

What layer of the digestive tube includes the Myenteric (Auerbach’s) nerve plexus?

Answer 25

The muscularis externa of the digestive tube includes the Myenteric (Auerbach’s) nerve plexus

Question 26

What is the function of the Muscularis Externa of the digestive tube?

Answer 26

regulates the size of the lumen (circular layer of smooth muscle), regulates rhythmic movement of the GI tract (longitudinal layer of smooth muscle)

Question 27

What is the arrangement of muscle descending the esophagus?

Answer 27

transition from skeletal muscle in the upper 1/3 to a mixture of skeletal muscle and smooth in the middle third to smooth muscle in the lower third.

Question 28

What is the cellular histology of the mucosa of the esophagus?

Answer 28

stratified squamous nonkeratinized epithelium with mucous glands in the lamina propria and submucosa

Question 29

What is the cellular histology of the stomach?

Answer 29

simple columnar epithelium

Question 30

What are the 4 regions of the stomach?

Answer 30

cardia
fundus
body
pylorus

Question 31

What region of the stomach contains mostly mucous glands?

Answer 31

cardia

(pylorus also contains mucous glands and hormone-secreting enteroendocrine glands

Question 32

What region of the stomach contains gastric glands composed of mucous neck cells, chief cells, stem cells, and enteroendocrine cells?

Answer 32

fundus and body

Question 33

What are rugae of the stomach?

Answer 33

longitudinal mucosal folds that are most prominent in an empty stomach.