Histo Accessory Digestive I

Front 1

What is the origin of the tongue?

Back 1

-derived from pharyngeal endoderm.

-invested with skeletal muscle (myotome origin),

-innervated by cranial nerves- ectoderm

Front 2

How is the tongue innervated? What does this allow for?

Back 2

cranial nerves 5,7,9,12

sensation, taste, motility

Front 3

Which side of the tongue has taste buds?

Back 3

dorsal surface

Front 4

What is this V-shaped structure on the dorsal surface of the tongue? What is the dorsal surface lined with?


Back 4

vallate papillae
papillae


Front 5

How can you distinguish papillae from each other?

Back 5

presence or absence of taste buds

Front 6

What structure surrounds taste buds? What function does it serve?

Back 6

Furrow - increases surface area to trap molecules for taste bud "assessment"

Front 7

The tongue is composed of a ________ core, with muscosa covering _______________ epithelium.

Back 7

skeletal muscle

stratified squamous

Front 8

What histological features can you identify in this slide:


Back 8

-Strat squamous
-no pillae
-cells at the basal surface are numerous = growth center
-inpocketed CT areas
-skeletal muscle deep to the CT
[it's the tongue!]

Front 9

So this is the tongue:

What features are these?

Back 9

mucous cells (gray arrow)
serous cells (green arrow)
cross and longitudinal sections of skeletal muscles
adipose

Front 10

What are the three types of papillae? How can you distinguish them?

Back 10

1) Filiform papillae are pointy; absence of taste buds.
2) Fungiform papillae are scattered throughout tongue. They are mushroom-shaped with taste buds.
3) Circumvallate papillae are the largest. There are 7-12 found in a “V-shaped group”. They have many taste buds.

Front 11

Identify the type of taste bud:


Back 11

Filiform
-pointy, no taste buds
-epithelium covering papillae with a lamina propia below

Front 12

This image is from the tongue, identify the structures:


Back 12

taste buds!


Front 13

What type of nerve innervates the taste buds?


Back 13

gustatory afferent nerve (sensory)


Front 14

What type of papillae could this be? What is at its core?


Back 14

Fungiform - mushroom shaped, note the TB
CT at its core - lamina propia


Front 15

Is the stratified squamous epithelium that covers the papilla keratinized?

Back 15

Nope

non-keratinizing

Front 16

Can you identify the two types of papilla?
S

Back 16

Sure, fungiform and filiform


Front 17

What type of papilla is this:


Back 17

circumvallate papillae
-serous glands, taste buds

Front 18

What is the origin of the teeth?

Back 18

contributions of skin ectoderm (enamel organ/tooth bud) and ectomesenchyme- dental papillae (neural crest).

Front 19

Odontogenesis begins with formation of the ______ and
involves a series of _______ between the tooth bud and the
dental papillae.

Back 19

tooth bud

inductions

Front 20

What does the gross structure of the tooth include?

Back 20

the crown, root, and pulp cavity.

Front 21

What are the major structures of the mature tooth?


Back 21

enamel, dentin, pulp cavity, root canal, gingival epithelium (gum), peridontal ligament, cellular cementum, alveolar bone


Front 22

What are these structures of the mature tooth?


Back 22

cementum, bony socket, peridontal ligament, (the enamel cannot be seen because it is so hard that it gets lost when they cut to prepare the slide)


Front 23

The ___ is the center of the tooth that is made up of soft tissue, containing odontoblasts. Is this area innervated?

Back 23

pulp
yes! and highly vasularized

Front 24

Cells found in the dental pulp include ______ (the
principal cell), odontoblasts, and _______cells (e.g.
macrophages, granulocytes, mast cells and plasma
cells).

Back 24

fibroblasts

defense

Front 25

What are the three characteristics of dentin?

Back 25

-50-70% inorganic (like bone)
-capable of growth & repair
-secreted by odontoblasts via Tomes fibers extended into the dentin


Front 26

What are the 4 characteristics of enamel?

Back 26

- hardest substance in the body!
-contains enamelins & amelogen proteins (~90% inorganic material)
-no ability for growth/repair
-secreted by ameloblast cells (that die after deposition)


Front 27

Dentin is secreted by ________ while enamel is secreted by ________.

Back 27

odontoblasts, ameloblasts

[to remember ameloblast for enamel, think "enameloblast" and then remove the "en"]

Front 28

What are the key points of tooth development?

Back 28

1. dentinal pulp and enamel organ induce a tooth bud (bulge forms)
2. ameloblasts form on the apical surface while odontoblasts form on the basal surface
3. a stellate reticulum forms as the cells break up
4. secretion of enamel and dentin
5. essentially the components of the mature tooth form
6. the tooth pushes through the gum
*see diagram on page 4 of handout*

Front 29

Identify the components of the newly formed tooth:


Back 29



Front 30

Why are ameloblasts not typical epithelial cells? What is this phenomenon referred to as?

Back 30

They secrete their exocrine product (enamel) basally!!

[basal products are usually hormonal- endocrine]

-said that they "reverse their polarity"

Front 31

What is this an image of:


Back 31

developing tooth

Front 32

Label these components of the mystery organ:


Back 32

developing tooth!


Front 33

Odontoblasts line the pulp cavity and extend _______ into the dentin.

Back 33

Tomes fibers

Front 34

Is dentin a living tissue?

Back 34

Yes

can grow/repair and react to pathologic (disease) and physiologic (functional) stimlui

Front 35

Which is harder, dentin or bone?

Back 35

dentin! (50-70% inorganic)

but enamel wins.

Front 36

Label these in order from pulp cavity to mouth surface:
dentin, ameloblasts, odontoblasts, enamel dentinoenamel junction. Where are the Tomes processes and tomes fibers?

Back 36

ondontoblasts, tomes fibers (into the dentin), dentin, dentinoenamel junction, enamel, ameloblasts (Tomes processes)


Front 37

What are these structures of the tooth:


Back 37



Front 38

What are the two proteins that are part of enamel?

Back 38

enamelins and amelogen

Front 39

What % of enamel is inorganic?

Back 39

90%, hence its strength

Front 40

What germ layer are ameloblasts derived from?

Back 40

derived from oral epithelium, of ectodermal origin

Front 41

What is a major histologic feature of enamel and how does it form?

Back 41

Tomes' processes

During the synthesis of enamel, the ameloblast moves away from the dentin, forming a projection surrounded by the developing enamel.

Front 42

What is this arrow showing?


Back 42



Front 43

What structure is this arrow pointing to? How do you know?


Back 43

Tomes fibers- penetration into the dentin! (vs. tomes' processes which don't penetrate...)


Front 44

Describe the cementum of the tooth.

Back 44

bone-like structure covering the root in a thin layer

-serves as an attachment for peridontal ligaments (tooth stability)

-upper portion is cemented to the dentin

-meets the enamel at the cemento-enamel junction.


Front 45

What are periodontal ligaments? What is their function?

Back 45

-fibrous dense CT

-stabilize the tooth by connecting the tooth to the bony socket
=each tooth has individual movement

-shock absorption (from chewing)


Front 46

What is another name for the mucosa covering the alveolar processes of the teeth? What is its function?

Back 46

gingiva

supports teeth and protects alveolar processes and the peridontal ligament from bacterial infection

Front 47

Are odontoblasts part of an epithelium?

Back 47

No! They don't rest on the basal lamina.

Front 48

Name these parts of the developing tooth:

Back 48

5. pulp cavity
4. odontoblasts
3. dentin (white stripes are Tomes fibers)
2. enamel
1. ameloblasts