L2-Salivary Glands

Question 1

How do alpha-amylase and lipase enzymes contained in saliva help begin digestion?

Answer 1

Alpha-amylase - Breaks down starches

Lipase - Breaks down lipids

Question 2

What role does Gustin, a compound contained in saliva, play in taste?

Answer 2

Gustin is a salivary growth factor required for growth and maturation of taste buds. If deficient in saliva, taste is impaired and taste bud morphology is disturbed.

Question 3

What is Lysozome’s antimicrobial function in saliva? Where else might lysozyme be found?

Answer 3

Lysozome hydrolyses bacterial cell walls. Found in saliva, tears, animals, plants, viruses as an essential part of a Primitive Defense System.

Question 4

What is Lactoferrin’s role in preventing microbial growth?

Answer 4

Lactoferrin binds free iron, depriving bacteria of this nutrient.

Question 5

What are the roles of Histatin and Cystatin in antimicrobial activity in saliva? Describe each Very briefly.

Answer 5

Histatin: A histadine rich protein that binds to membranes of pathogens and weakens them by increasing permeability.
Cystatin: Cysteine rich proteins that function as Protease inhibitors in all muccosal secretions. Thus, protecting against proteases released by microorganisms.

Question 6

What is a common antibody found in saliva that is made by plasma cells in the connective tissue capsules? In what way does saliva act to prolong the life, therefore increasing the effectiveness of, the above antibody?

Answer 6

IgA. IgA combines with a peptide made by salivary glands. The peptide makes IgA resistant to digestion by enzymes in the oral cavity.

Question 7

What are the two main components of hydroxyapatite that are kept at high concentrations within saliva? Which is maintained at high levels by Acidic proline rich proteins (PRPs) found only in saliva?

Answer 7

Calcium and phosphorous. PRPs continually keep Ca at high levels in saliva.

Question 8

What is the function of epidermal growth factor (EGF) in saliva?

Answer 8

It helps stimulate new tissue growth after a wound. I.e. Cat or dog licking wound actually increasing healing process.

Question 9

Trace the path of secretions w/in the salivary glands from production to the oral cavity.

Answer 9

Secretory cells (serous, mucous w/ serous demilunes, and mucous) produce different secretions within the acini, the secretory end piece. From there the secretions are dumped into the intercalated ducts then to the striated and finally to the excretory ducts before being released into the oral cavity.

Question 10

Salivary glands are formed from week 4-8 of fetal development, transforming from small cord of cells to specific glands w/ septa, with ducts and blood vessels, surrounding lobules filled with acini. What is believed to govern this developmental process?

Answer 10

Ectomes.

Ectomes have signaling power to form salivary glands. Very specific for location.

Question 11

What is the nuclei shape and location within serous cells?

Answer 11

Round nuclei located in basal third of cell.

Question 12

Compare the secretions of serous and mucous secreting cells. Where are both found?

Answer 12

• Serous cells produce a water secretion, rich in proteins (causes the secretory vessels to stain darkly). High concentration in parotid gland, medium concentration in submandibular gland, not found in sublingual glands.
• Mucous cells produce a viscous secretion, rich in polysacharides. Found in submandibular (medium concentration) and sublingual (High concentration).

Question 13

Describe the shape and location of the nucleus w/in mucous cells.

Answer 13

Flat nuclei on bottom of cell near basement membrane.

Question 14

What are serous demilunes? Where are they found?

Answer 14

Serous demilunes are attachments to mucous secretory cells that produce serous secretions. Found in both submandibular and sublingual glands.

Question 15

What are myoepithelial cells?

Answer 15

Myoepithelial cells are found wrapped around secretory end pieces in contact with individual secretory cells. They are believed to have contractile properties that support the acini during secretion and assist in maintaining the ducts.
Note: ‘myo’ = muscle. Muscles contract…

Question 16

Describe intercalated ducts? Cell type and nuclei shape/location?

Answer 16

Receive secretions from acini. Transports secretions to striated ducts modifying them slightly (has minor secretory function).
Small, Cuboidal Epithelial cells with round central nuclei.

Question 17

Describe striated duct cells. Cell type? Basal striations?

Answer 17

• Receive secretions from intercalated ducts. Pass secretions to excretory ducts.
• Larger ducts w/ columnar cells having basal striations
• Basal striations are deep indentations of the basal membrane. Oriented parallel with a high concentration of mitochondria, which are necessary for the pumping activity of the striations.

Question 18

As secretion moves through the duct system, the composition is modified by the reabsorption and secretion of electrolytes.
What two electrolytes are reabsorbed? Why?
What electrolyte is secreted?

Answer 18

Na- and Cl- are reabsorbed to create a hypotonic saliva.

Bicarbonate is secreted

Question 19

Despite modification of secretions w/in the duct system saliva remains 99% water. Where is this water obtained from?

Answer 19

Blood.

Question 20

Exocytosis of proteins is stimulated by what physiological action? i.e. not just food ingestion

Answer 20

Sympathetic neurotransmitters such as norepinephrine.

Question 21

What is the main secretion of minor salivary glands? Where are minor salivary glands found?

Answer 21

Mucous secretions.
Minor salivary glands are found in submucosa throughout the oral cavity.
-Labial
-Lingual
-Buccal
-Palatine

Question 22

Sjogren’s syndrome is an inflammatory and autoimmune disease possibly cause by infliltration of lymphocytes into lacrymal and salivary glands where they produce auto-antibodies. What are the effects of this disease?

• What is one lymphocyte maturation gene that has been shown to cause similar symptoms?
• Why would a mutation in human aquaporin-5 gene lead to sjogren-like symptoms?

Answer 22

Glandular disfunction and decreased secretion resulting in xerostomia.

• Id3 gene
• Aquaporin-5 is a water channel. Aquaporins bring the water from blood cells into the duct system providing the 99% of saliva.

Question 23

What is a promising new way to identify early stage malignancies and other diseases throughout the body using saliva?

Answer 23

Biomarker Identification. Would identify differences in specific salivary biomarkers from the norm, that are synonymous with certain diseases or cancers.