Anatomy - Outcome 9

Question 1

Mucous membrane defined

Answer 1

It is the tissue that lines a body cavity that opens to the outside of the body; for example, a mucous membrane is found lining the:

oral cavity, nasal cavity, sinuses, trachea, stomach, intestines, urinary bladder, and uterus.
histologically it is a modified skin composed of:
outer (surface) layer of epithelial tissue – which has protective, secretory and absorptive function
underlying layer of connective tissue – which contains blood vessels, nerves and glands
it is not as tough as skin
it is kept moist
the histological structure of a mucous membrane is suited to the function it performs
the mucous membrane lining the oral cavity is heavier and more resistant to injury than the mucous membrane of more protected cavities (like the sinuses).
it allows the oral mucosa to withstand wear and tear from occlusion and to resist bacterial infection.

Question 3

Mucous Membrane Defined:

Answer 3

It is the tissue that lines a body cavity that opens to the outside of the body; for example, a mucous membrane is found lining the:

-oral cavity, nasal cavity, sinuses, trachea, stomach, intestines, urinary bladder, and uterus.
-histologically it is a modified skin composed of:
1. outer (surface) layer of epithelial tissue – which has protective, secretory and absorptive function

2. underlying layer of connective tissue – which contains blood vessels, nerves and glands

it is not as tough as skin
it is kept moist
the histological structure of a mucous membrane is suited to the function it performs
the mucous membrane lining the oral cavity is heavier and more resistant to injury than the mucous membrane of more protected cavities (like the sinuses).
it allows the oral mucosa to withstand wear and tear from occlusion and to resist bacterial infection.

Question 4

Oral mucosa is..

Answer 4

is the name given to the mucous membrane that lines the oral cavity

Question 5

Epithelial Tissue Layer is..

Answer 5

-composed of stratified squamous cells (flat and several layers deep)
-in protected areas (cheeks, lips, ventral surface of the tongue), the surface epithelial cells are sloughed off as new epithelial cells are produced in the basal layer
-in areas of more wear/tear (gingiva, hard palate, occlusal line on buccal mucosa), surface epithelial cells are not sloughed. Instead, they lose their nuclei and cell boundaries and a non-cellular, tough protected layer that covers the surface of the stratified squamous epithelial cells and is called a keratinized epithelial layer (as it wears it is replaced with aging cells beneath). You can feel this keratinized epithelial layer on the line of occlusion on your buccal mucosa

Question 6

Connective Tissue Layer (Lamina Propria):

Answer 6

-it is a fibrous connective tissue containing blood vessels and nerves

-note that the boundary between the epithelial tissue and connective tissue is an irregular boundary with projections (like fingers) of connective tissue extending up into the epithelial tissue. These projections of connective tissue are called rete pegs. This irregularity between the 2 tissue layers serves to increase the surface area from which epithelial tissue receives nourishment from the connective tissue

-connective tissue varies in thickness in different parts of the mouth and it varies in how it is attached to the tissue below it. For example:
*in the cheek, the connective tissue of the oral mucosa rests upon a looser type of connective tissue called submucosa, which consists of nerves, glands, larger blood vessels and fat tissue
*in the gingiva attachment to underlying tissue is tight because it is attached to alveolar bone

Question 7

Rete Pegs are..

Answer 7

the boundary between the epithelial tissue and connective tissue is an irregular boundary with projections (like fingers) of connective tissue extending up into the epithelial tissue. These projections of connective tissue are called rete pegs

Question 8

Basement Membrane

Answer 8

The basement membrane lies between the epithelium and connective tissue. It is a continuous structure linking the two rather than separating them

Question 9

Subdivisions of Oral Mucosa:

Answer 9

Masticatory

Lining

Specialized

Question 10

Masticatory - Oral Mucosa

Answer 10

Areas of the oral mucosa that are the most used during the mastication of food. It is usually keratinized and includes:

gingiva
hard palate

Question 11

Lining - Oral Mucosa

Answer 11

Located in areas of the oral cavity where the mucous membrane functions as a “lining” rather than a masticatory organ. Lining mucosa is not keratinized and not firmly attached to tissue below it. It includes:

lips and cheeks
the floor of the mouth
the underside of the tongue
soft palate
alveolar mucosa

Question 12

Specialized - Oral Mucosa

Answer 12

Applies to the mucous membrane located on the dorsal surface of the tongue. The entire surface of the tongue is composed of innumerable small papillae and some of them contain organs that supply the sense of taste. The papillae can attract a toothpaste residue on the tongue, a whitish or slightly coated appearance that should not be confused with a yeast-like infection of the tongue.

Question 13

Gingiva - Location

Answer 13

part of the oral mucosa
surrounds crevices of teeth
attaches to alveolar process (firmly)
buccal, labial, lingual, palatal regions

Question 14

Parts (types) of Gingiva

Answer 14

Attached Gingiva - Apical to free gingiva.
Firmly attached to the tooth & underlying bone.

Interdental Gingiva (papillae) - Fill the area between teeth apical to their contact areas

Free Gingival Margin - Surrounds the tooth in a ‘collar’ like fashion

Question 15

Clinical Appearance of Gingiva (Healthy Tissue)

Answer 15

Surface Texture:
free gingiva – smooth
attached gingiva – stippled
interdental - central portion-stippled and marginal border- smooth

Color:
uniformly pale pink or coral pink
variations in pigmentation due to complexion or race
extends from gingiva margin to mucogingival junction
palatal – color blends with the roof of the mouth (attached to bone)

Size:
not enlarged
fits snugly around one tooth

Shape (Contour):
Marginal gingiva - knife-edged, flat, follows a curved line around the tooth
Papillae - normal contact → papillae are pointed, fills the interproximal space
diastema: gingiva is flat or saddle-shaped

Consistency:
firm
attached gingiva firmly bound to tooth

Question 16

The position and shape of gingiva depends on the age of the individual (interproximal space and interdental papilla)..

Answer 16

Young – interdental papillae fill the interdental space
Clinical crown < anatomical crown

Age 30-40 – interdental papillae fills the interdental space
Clinical crown = anatomical crown

Age 50-60 – interdental papillae do not fill the interdental space
Clinical crown > anatomical crown
dentin visible

Question 17

Histologic Structure of Gingiva

Answer 17

-connective tissue (lamina propria)
-epithelial tissue (stratified squamous keratinized)
-keratinization gives color
-finger-like projections of connective tissue
-Fibers of PDL in connective tissue
*Transseptal
*Alveolar crest fibers
*Free gingiva fibers

Question 18

Gingival Sulcus

Answer 18

-space or crevice surrounding the tooth (between the free gingiva and tooth)
-border of non-keratinized gingiva (not attached to the tooth or alveolar bone)
-the normal depth of 1-3 mm
Borders:
*tooth (inner wall)
*sulcular epithelium (non *keratinized – outer wall)
*junctional epithelium (bottom)
*gingiva margin (top)

Question 19

The Epithelial Attachment

Answer 19

-junctional epithelium
-stratified squamous (not keratinized)
-continuous with sulcular epithelium to gingiva margin
-over the gingiva margin to outer keratinized gingiva
-normal apical migration with wear
-disease apical migration
-not keratinized

Question 20

Glandular Tissue

Answer 20

-Glands are secreting organs that produce a specific product or secretion.
-derived from an invagination of developing epithelial tissue
-some glands are classed as exocrine as their ducts open to the external surface of the body (e.g. sweat and salivary glands)
-secretions produced by exocrine glands may be serous, mucous or a combination of serous and mucous
-other glands are classed as endocrine (ductless) as their secretions enter the blood as hormones

Question 21

Salivary Glands

Answer 21

-Salivary glands are exocrine glands that secrete a colorless, slightly sticky fluid called saliva which is secreted into the oral cavity through ducts that open onto surfaces of the oral mucosa
-Embryologically speaking, salivary glands originate from ectoderm (later epithelial tissue) that lines the early oral cavity.
*In certain areas of the embryo’s oral cavity, oral epithelial cells grow decreasing in underlying connective tissue and as they multiply, these epithelial cells become modified and specialized to become salivary glands.
*Some of these cells become secretory cells of the salivary glands.
*Some of these cells become ducts (canals) of the salivary glands through which saliva flows into the oral cavity

Question 22

Types of Secretory Cells

Answer 22

Serous Cells
Mucous Cells

Question 23

Serous Cells

Answer 23

(contains ptyalin (salivary amylase)) that initiate breakdown of starches
*also secrete other components found in saliva.

Question 24

Mucous Cells

Answer 24

(contains mucin) - the lubricant to the oral cavity. *also secrete other components found in saliva.

Question 25

Salivary Glands are composed of…

Answer 25

Salivary glands are composed of serous cells or mucous cells or a combination of these two types of cells plus the ducts that connect the cells.

Question 26

Saliva is..

Answer 26

-a fluid that can be collected by expectoration (spitting)
-the film that bathes the surface of the mucosa and teeth

The total amount varies in individuals but it is approximately one litre a day

Question 27

Composition of Saliva..

Answer 27

Its composition includes:

1.secretions from the various salivary glands
2. sloughed epithelial cells
3. leukocytes
4. bacteria
5. subgingival sulcus fluid
6. organic compounds; i.e., proteins and glycoproteins (protein concentrations increase with the rate of flow of saliva)
7. inorganic components: Na+ (cations), K+ (cations), Ca++ (cations) P04- (ions) (sodium concentrations increase with the rate of flow)

Question 28

Thyroid Gland

Answer 28

The thyroid gland is the largest endocrine gland. It is a ductless gland that produces and secrets hormones directly into the blood. It is the biggest gland in the neck, situated in the anterior of the neck below the skin and muscle layers.

Thyroxin is the hormone secreted that stimulates metabolic rate and is needed for normal growth.

Question 29

Lymph Nodes

Answer 29

The lymph nodes are part of the lymphatic system. They are small round structures located in the lymph vessels. Major lymph node sites are the cervical nodes in the neck, axillary nodes under the arms, and inguinal nodes in the lower abdomen

Question 30

The Salivary Glands

Answer 30

The major salivary glands are three pairs of glands that produce the bulk of the fluid in the mouth. This is saliva, which is 99% water, and which is mixed with food to make it easy to swallow. Saliva begins to break down starches into smaller carbohydrate units. Further breakdown takes place in the stomach

Question 31

Functions of Saliva Glands

Answer 31

1. assist in the mastication of food
2. serve as a solvent
3. contributes to the digestion of CHO
4. lubrication of food and oral tissues
5. acts as a buffer against bacterial acids (this buffering action helps to make the oral cavity less susceptible to decay and less suitable for the growth of certain bacteria
6. cleanses the mouth by flushing out debris
7. moistens and lubricates segments of the respiratory mucosa as required
8. speech
9. remineralization

Question 32

A decrease in the flow of saliva can result in:

Answer 32

1. stomatitis; i.e. irritation/inflammation of the oral mucosa
2. speaking problems
3. swallowing problems

Question 33

Minor Salivary Glands

Answer 33

-vary in size and are widely distributed beneath the oral mucosa
-they are similar in structure to the major salivary glands but have fewer secretory units and fewer ducts
-function to supply minor amounts of saliva that wet mucosa
-located on the upper and lower lip surface, the inner lining of the cheek, and the surface of the soft palatal tissue

Question 34

Major Salivary Glands

Answer 34

-exist as a pair
-Parotid salivary glands contain serous (thin, watery) type saliva comprising 25% of total saliva volume
-Submandibular glands contain 2/3 serous and mucinous type saliva comprising 60% of total saliva volume
-Sublingual glands contain primarily mucinous and some serous type saliva comprising 15% of total saliva volume

Question 35

The Parotid (Stenson’s) Duct:

Answer 35

The Parotid gland is located on the side of the face near the ear and behind the extension of the lower jaw.

It is composed of many grapelike clusters of cells, which secrete into a system of tubes leading to the oral cavity.

Although these are the largest of the salivary glands, they only produce about 25% of the total salivary volume.

Saliva is conveyed to the mouth by the Parotid or Stenson’s duct which opens into the mouth opposite the second maxillary molar.

Mumps is a virus infection of the Parotid gland, causing pain when the gland secretes. Thus, eating at this time is quite painful because it causes stimulation of the gland.

Question 36

Submandibular Gland:

Answer 36

The submandibular gland provides about 60% to 65% of the total volume of saliva. It is about the size of a walnut and is located below and towards the posterior part of the body of the mandible.

Place your finger on the inferior border of the mandible and run it back toward the angle of the mandible. You will feel a slight depression. Move your finger medially and you will feel a lump in the neck. That is the submandibular gland.

Saliva is conveyed to the mouth by Wharton’s duct which opens onto a small elevation called the sublingual caruncle.

Question 37

Sublingual Gland

Answer 37

The sublingual gland is the smallest of the glands and contributes only 10% of the total salivary volume.

It is located on the anterior floor of the mouth next to the lower cuspids. It has one major duct which opens with the submandibular duct and several smaller ducts which open in a line along the sublingual fold.

Question 38

Functions of Saliva

Answer 38

-moistens and lubricates the mouth and food to make swallowing easier
-washes away some food particles adhering to the teeth
-initiates the digestive process
-forms a protective layer over the tooth surfaces
-supplies minerals for the process of remineralization; but also for calculus formation

Question 39

Sialolith

Answer 39

is the name given to calcified material that blocks or plugs a salivary gland duct. Occasionally, a salivary gland duct can be blocked by a plug. If the plug becomes calcified, it is referred to as a sialolith. A sialolith is often seen in the duct or canal of the SMG.

Question 40

Mucocele

Answer 40

(a blister filled with saliva). When the duct of a minor salivary gland becomes severed, a clear, fluid-filled blister-like lesion is noted. This is a result of saliva accumulating in the connective tissue spaces of the mucosa.

Question 41

Ranula

Answer 41

a mucocele that forms unilaterally on the floor of the mouth

Question 42

Flow of saliva

Answer 42

All major and minor salivary glands are controlled by the autonomic nervous system. Therefore the presence of food or something in the mouth will cause salivation
There are a number of medications that cause excess salivation but there are even more that, when used for a prolonged period of time, will reduce the flow of saliva
NOTE: Many medications cause a dry mouth (xerostomia).

The patient’s Health History regarding medications might clarify why there might be more or less than normal amounts of saliva. The reduced flow of saliva may contribute to “oral mucosal abrasions”, “mucosal irritation” and “dental decay.”

Question 43

The function of the Lymphatic System:

Answer 43

The lymphatic organs contribute to the immune system by helping to destroy harmful microorganisms.

Question 44

Lymph Vessels

Answer 44

a system of tubes similar to veins that carry lymph fluid that is clear and colourless. This fluid flows in the space between cells and tissue to carry substances from these tissues back into the bloodstream. It can return proteins or transport fat as well as bring bacteria to the lymph nodes.

Question 45

Lymph Nodes

Answer 45

oval structures fight disease by producing antibodies. In an infection, the nodes become swollen and tender as a result of the lymphocytes collecting to destroy the invading bacteria

Question 46

Lymph Organs

Answer 46

there are two secondary organs that contribute to the immune system

-Tonsils
-Spleen

Question 47

Tonsils

Answer 47

Tonsils are a mass of lymphatic tissue located in the upper portions of the now and throat. Their function is to destroy invading microorganisms; they may become infected in the process.

Question 48

3 Types of Tonsils

Answer 48

There are 3 tonsil types. During a tonsillectomy, all three are removed.

• nasopharyngeal tonsils (adenoids) - found in the nasopharynx

-palatine tonsils - located in the oropharynx between the anterior and posterior pillars of the throat. These are visible in the mouth.

-lingual tonsils - which are located on the back of the tongue.

Question 49

The Spleen

Answer 49

The spleen is the largest of lymphoid organs, located in the upper left of the abdomen, below the diaphragm, and behind the stomach. It filters microorganisms and other debris not destroyed by the lymphatic system. it also stores red blood cells and removes worn-out red blood cells.

Question 50

Swelling of Thyroid Gland

Answer 50

-When disease is present, the thyroid gland may become enlarged enough to be viewed during an extraoral examination. It may be firm and tender when palpated or contain hard masses.
-if the patient did not note these symptoms or diagnosis on their medical history, they should be referred to a physician.

Question 51

Hyperthyroidism

Answer 51

-This condition occurs when a patient has an overactive thyroid gland which produces more hormone than the body needs.
-patients who are not diagnosed or who are not being treated are highly sensitive to epinephrine and other amine anesthetics.

Question 52

Hypothyroidism

Answer 52

-This condition occurs when the thyroid gland is underactive and does not produce enough hormone.
-There is generally not a concern during dental treatment with the condition, but some of the medication to treat the condition may be sensitive to narcotic analgesics, barbiturates, and tranquilizers.

Question 53

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