Lab 8: Digestive system I

Question 1

name main parts of erupted tooth

Answer 1

clinical crown
anatomical crown
root

Question 2

describe clinical crown (erupted tooth)

Answer 2

enamel
dentin

Question 3

describe anatomical crown (erupted tooth)

Answer 3

gingiva (cuticle)

mucogingival junction
pulp
odontoblasta
alveolar bone

Question 4

describe root (erupted tooth)

Answer 4

periodontal ligament
cementum - cementocytes
apical foramen

Question 5

what must be done for erupted tooth to be sectioned

Answer 5

enamel must be removed to tissue can be sectioned

Question 6

what is enamel space

Answer 6

space in between dentin and gingiva

Question 7

describe gingiva

Answer 7

parakeratinized stratified squamous epithelium

Question 8

describe dentin

Answer 8

70% hydroxyapatite
30% organic material which contains collagen type 1
secreted by odontoblasts as pre dentin (paler than dentin)

Question 9

describe odontoblasts

Answer 9

columnar cells with processes running in dentin = dentin canaliculi (long processes that run through the dentin as tunnels)
basophilic cytoplasm
nuclei located at base of cell

Question 10

describe pulp

Answer 10

contains collagen type 1 and 2
fibroblast cells
blood vessels, lymphatics and nerves
lined by odontoblasts

Question 11

what are sharpeys fibers

Answer 11

insertion of periodontal ligament

Question 12

where are osteoclasts

Answer 12

in between alveolar bone and periodontal ligament

Question 13

describe periodontal ligament

Answer 13

dense regular ct
origin in alveolar bone and insertion into cementum (sharpey’s fibers)

Question 14

describe cementum

Answer 14

thinner
located on side of tooth
acellular
thicker at bottom or root of tooth and can be considered cellular (cementocytes)
play a role in passive eruption

Question 15

describe mature enamel

Answer 15

99% inorganic material
made of hydroxyapatite crystals

Question 16

describe immature enamel

Answer 16

70% inorganic material
30% amelogenin
more basophilic than dentin

Question 17

describe enamel of unerupted tooth

Answer 17

softer
does not need to be removed during prep of slides

Question 18

describe root sheath

Answer 18

where IDE and ODE come together
separated by stellate reticulum and stratum intermedium
demarcates end of clinical crown and beginning of root sheath

Question 19

what is pre enamel

Answer 19

THERE IS NO SUCH THING AS PRE ENAMEL

Question 20

does enamel contain collagen

Answer 20

HECK NO

Question 21

what is enamel organ

Answer 21

responsible for producing enamel
not present in erupted teeth

Question 22

name parts of enamel organ

Answer 22

outer dental epithelium (ODE)
stellate reticulum
stratum intermedium
inner dental epithelium (IDE)

Question 23

describe ODE

Answer 23

Continuous with stratum germinativum of the skin
Squamous cell layer

Question 24

describe stellate reticulum

Answer 24

wide intercellular spaces are present
largest area of enamel organ
cells here are stellate or star shaped

Question 25

describe stratum intermedium

Answer 25

resembles stratum spinosum of skin
polygonal shaped cells
1-3 layers of cells

Question 26

describe IDE

Answer 26

made of ameloblasts
Continuous with stratum germinativum of oral epithelium
cells are columnar and rest on BM
cells have short processes that project into enamel (Tones processes)

Question 27

describe enamel (of enamel organ)

Answer 27

enamel layer
at bottom

Question 28

describe tongue

Answer 28

mass of skeletal muscle
covered by oral mucosa
has papillae

Question 29

what is oral mucosa

Answer 29

non keratinized stratified squamous epithelium

Question 30

name 3 types of papillae

Answer 30

filiform papilla
fungiform papilla
circumvallate papilla

Question 31

describe filiform papilla

Answer 31

along midline of tongue
most abundant papilla
shaped like toothpick
nonkeratinized at base but can be keratinized at tip
not involved in taste

Question 32

describe fungiform papilla

Answer 32

on side and tip of tongue
Mushroom shaped
very few in number
lined by non keratinized stratified squamous epithelium

Question 33

describe circumvallate papilla

Answer 33

located along lingual V
large and spherical in shape
has a deep groove lined with oral mucosa
taste buds = found in grooves
von ebners gland

Question 34

describe von ebners glands

Answer 34

serous secretion
secretes lingual lipase
found at base of circumvallate papilla in submucosa
function = to wash particles from taste bud

Question 35

name 4 main layers of esophagus

Answer 35

mucosa
submucosa
tunica muscularis
adventitia/serosa

Question 36

describe epithelium of esophagus mucosa

Answer 36

non keratinized stratified squamous epithelium

Question 37

describe lamina propria of esophagus mucosa

Answer 37

loose irregular ct
contains esophageal cardiac glands (located in upper and lower thirds)

Question 38

describe muscularis mucosa of esophagus mucosa

Answer 38

thin layer of longitudinally oriented smooth muscle

Question 39

describe esophagus submucosa

Answer 39

loose irregular ct
esophageal glands proper (mucous glands found throughout)

Question 40

describe 3 parts of tunica muscularis of esophagus

Answer 40

upper third: skeletal muscle (voluntary)
middle third: skeletal and smooth muscle
lower third: smooth muscle (oblique orientation)

Question 41

describe adventitia and serosa of esophagus

Answer 41

adventitia = dense irregular ct (present until esophagus traverses the diaphragm)
serosa = thin layer loose ct covered by mesothelium (simple squamous epithelium)

Question 42

describe parakeratin

Answer 42

not composed of dead cells like keratin layer of skin
appears eosinophilic - not basophilic like that of skin