Biology of the Salivary Glands 513 (KEY) MID-TERM Examination June 2, 1997

Transcription

1 Biology of the Salivary Glands 513 (KEY) MID-TERM Examination June 2, Which of the following is least essential for the salivary gland development? a. Cytodifferentiation of secretory acinar cells. b. Interaction between the epithelial bud (salivary gland bud) and appropriate mesenchyme. c. Parallel differentiation of autonomic nerve axons. d. Recruitment of plasma cells for secretory IgA production. (D) 2. The microscopic examination of a biopsy sample from a salivary gland revealed serous demilunes and a large number of lipid granules, as well as lipofuscin granules. The sample is most likely to be from the: a. Sublingual gland of a 25 year old person. b. Parotid gland of a 25 year old person. c. Submandibular gland of an 80 year old person. (C) d. von Ebner s gland of an 80 year old person. 3. The stimulated secretion of salivary gland acinar cells through β- adrenergic receptors will involve which of the following changes: a. Appearance of cytoplasmic vacuoles. b. Fusion of secretory granule membranes with the apical cell membrane. (B) c. Increase in chromium concentration d. Termination of transepithelial protein transport e. Reversal of constitutive exocytosis. The diagram for questions 4 and 5 will be found on the next to last page of this exam. 4. The segment of the salivary gland duct responsible for the modification of primary saliva to a hypotonic solution rich in potassium and bicarbonate ions is lined by which cell? (B) Page 1 of 8

2 5. The acini of the parotid gland are made up of which cell? (A) 6. The concept of multifunctionality of the salivary proteins refers to the observation that: a. for any biological or chemical activity in saliva there are often several proteins that perform that activity. (A) b. when salivary proteins enter the serum they demonstrate different biological activities. c. as salivary proteins mature they change their biological and chemical activities. d. none of the above. e. all of the above. 7. One advantage of heterotypic complexing of salivary proteins is that: a. it allows mucins of the same type to bind to one another to create large complexes. b. it enhances lubrication by mucins of the same type. c. distinct characteristics of each member of the complex can be combined to enhance the functional activity of one or both of the members of that complex. (C) d. all of the above. 8. It is thought that the salivary amylases have a role beyond that of nutrition because: a. hydrolysis of starch is not an important nutrient pathway. b. amylases are directly cytotoxic to bacterial cells. c. amylases play a role in degradation of lipids, releasing antimicrobial fatty acids. d. the same enzymes are found in tears, serum, bronchial, and urogenital secretions. (D) Page 2 of 8

3 9. Why is it important to maintain supersaturated calcium phosphate levels in saliva? a. It is important to have constant precipitation of calcium phosphate onto the enamel surface to thicken the pellicle. b. High concentrations of calcium phosphate are microbicial. c. Calcium phosphate salts in enamel are soluble and in the absence of supersaturated levels in oral fluids, enamel integrity would suffer. (C) d. Supersaturation maintains solubility of salivary proteins. e. All of the above. 10. The pellicle serves as: a. a diffusion barrier, slowing attacks by bacterial acids and loss of dissolved calcium and phosphate ion. b. a means of concentrating salivary proteins that play a role in defense of the tooth surface. c. a site of adherence for selected microorganisms. d. all of the above. (D) Questions Using your knowledge of the two-stage hypothesis of salivary secretion and data presented in class on the concentration of primary saliva, answer the following questions regarding the results of such an experiment. (Refer to the figures labeled a through e on the last page.) 11. Which of the following graphs (a-e) represents the concentration of Na + that you predict you would record in such and experiment? (D) 12. Which of the following graphs (a-e) represents the concentration of K + that you predict you would record in such and experiment? (E) 13. If you used an ion channel blocker to prevent movement of Na + ions across cell membranes which graph (a-e) would represent the concentration of Na + ions that you predict you would record in such an experiment? (C) 14. Which of the following graphs (a-e) provides scientific evidence that Na + ions are resorbed as they pass down the ducts? (D) Page 3 of 8

4 15. Which of the following graphs (a-e) provides scientific evidence that K + ions are secreted as they pass down the ducts? (Sorry, the graphs are no longer available) (E) 16. The parasympathetic secretomotor neurons controlling von Ebner s glands are located in: a. the superior salivatory nucleus. b. the inferior salivatory nucleus. (B) c. the trigeminal nucleus. d. the intermediolateral nucleus. e. the solitary nucleus. 17. If you eat lemon your saliva: a. is high in salivary amylase b. flows at about 10 µl/min. c. flows at about 100 µl/min. (C) d. has a ph of about 6.6. e. has a bicarbonate concentration of about 0.6 meq/l. 18. Which of the following is not a general rule that applies to all salivary glands? a. Secretomotor autonomic nerves invariably control flow. b. Osmotic pressure (tonicity) exerted by saliva is usually higher than that of plasma. (B) c. Tonicity increases as the flow rate of saliva increases. d. Saliva contains potassium ions at 2-10 times the concentration of serum potassium. e. Saliva contains high levels of amylase. Page 4 of 8

5 19. If you sampled primary saliva under control conditions and after either an injection of carbachol or isoproterenol the composition of primary saliva a. is isotonic with plasma. (A) b. has a higher concentration of Na + ions after carbachol when compared to control levels. c. is hypotonic after isoproterenol. d. has a higher concentration of Na + ions after isoproterenol when compared to control levels. e. is hypotonic after carbachol. 20. A patient comes into your office complaining of a persistent dry mouth. Which of the following is the most likely explanation of this condition? a. The patient lectures to dental students all day without taking a drink of water. b. The patient is taking medication containing a muscarinic blocker. (B) c. The patient is taking medication that blocks β-adrenergic receptors. d. The patient is a professional baseball player and spits constantly. e. The patient likes to eat hot chili peppers. 21. Each stage of the protein secretion process is regulated by a. osmotic pressure. b. peptidergic receptors triggering. c. polymeric Ig receptors. d. phosphorylation of target proteins (D) Page 5 of 8

6 22. Constitutive exocytosis is a process by which a. the constitution of the acinar cell membrane determines the rate of secretion of proteins. b. regulation of protein secretion occurs at the biosynthesis stage. c. there is a continuous flow of protein in small vesicles to the plasma membrane. d. b and c (D) e. none of the above 23. Cyclic AMP is referred to as a second messenger because a. if a cell cannot be triggered via its specific receptor, camp provides an alternate pathway. b. once it is produced, as a result of specific stimulation of a receptor, it controls numerous processes within the cell. (B) c. camp is released by cells to enable triggering of distant cells. d. two signals interacting with the cell surface receptors are required for triggering the cell. 24. What is the meaning of crosstalk? a. The separation between the control of protein and electrolytes breaks down at the second messenger level. (A) b. The same receptor triggers numerous events. c. Activation of a single acinar cell results in triggering cells next to it. d. all of the above. 25. Transepithelial transport of siga is necessary because a. siga is also synthesized within the acinar cells. b. camp is not involved in its regulation. c. it must cross epithelial cell barriers. (C) d. all of the above. Page 6 of 8