BISC 307, Spring 2012 Exam 4, Posted Answers 1. The table below presents results of blood cell counts taken 10 days and 20 days after a patient received chemotherapy treatment for leukemia. Cell Type Normal Range Day 10 Day 20 Leukocytes 4.5 - 10.3 (103) 2.7 5.0 Erythrocytes 4.5 - 5.3 (106) 4.0 4.2 Platelets 1.4 - 4.1 (102) 1.4 1.8 On day 10, which one of the following sets of symptoms/characteristics would the patient most likely exhibit? a. pale and easily fatigued b. likely to bleed easily or excessively c. is at high risk for infections -ANS 2. A person was diagnosed with hemophilia due to a deficit in clotting factor XI. Which one of the following would be true for this person? a. The person would not have a functional intrinsic pathway. -ANS b. The person would not have a functional extrinsic pathway. c. The person would not have a functional common pathway. d. The person’s clotting times would be shorter than normal. e. All of the above would be true. 3. Indicate whether each of the following statements is likely to be true or false by writing the word “True” or “False” in the blank. Do not write T or F. ___________ a. Interferons provide a nonspecific defense against viral infection. (T) ___________ b. The Fab fragment of antibodies contains the light chain and part of the heavy chain. (T) ___________ c. Neutrophils, macrophages, and dendritic cells have toll-like receptors on their surfaces that enable them to recognize bacteria and viruses. (T) ___________ d. Immediate allergic responses occur when antigens bind to IgA antibodies on the surfaces of mast cells. (T) 4. The acquired immune defenses involve both humoral immunity and cell-mediated immunity. Indicate to which type of immunity each of the following statements applies. Answer by writing “H” in the blank for humoral immunity, “CM” for cell-mediated immunity, or “Both” if both apply. ANS: a-H, b-CM, c-Both, d-CM, e-Both, f-H ________ a. Involves B cells. ________ d. Involves class I MHC molecules. ________ b. Involves cytotoxic T cells. ________ e. Responds to viral infection. ________ c. Involves helper T cells. ________ f. Responds to extracellular bacterial infection. 5. Which one of the following statements is false? a. Most antigens induce a response from more than one clone of B cells.2 b. IgG functions more effectively than IgM in causing bacterial agglutination. -ANS c. Macrophages express both type I and type II MHC molecules on their surfaces. d. The skin’s reaction to contact with poison oak is an example of a delayed hypersensitivity. e. A primary defense against the attachment of viruses and bacteria to epithelial surfaces is IgA. 6. Which one of the following statements about how B and T cells recognize antigens is true? a. B cells only recognize antigens presented by class I or class II MHC molecules. b. Both B and T cells can recognize antigens in solution without the assistance of other cells. c. Both B and T cells can recognize antigens bound to the extracellular matrix. d. T cells only recognize antigens presented by class I or class II MHC molecules. -ANS 7. Indicate whether each of the following statements is likely to be true or false by writing the word “True” or “False” in the blank. Do not write T or F. ___________ a. Monocytes are blood-borne precursors of macrophages. (T) ___________ b. Lymphatic vessels draining extracellular spaces in tissues enter the spleen. (F) ___________ c. Both T and B lymphocytes have antigen-binding receptors on their surface. (T) ___________ d. Activation of macrophages increases their expression of type I MHC molecules, which allows them to present antigens more effectively. (F) 8. Briefly describe 3 features of a secondary immune response that distinguish it from a primary immune response. ANS: 1) The secondary immune response involves activation of a large population of memory cells. 2) The secondary immune response is more rapid than the primary immune response. 3) The secondary immune response achieves higher levels than the primary immune response. 9. Which one of the following statements about the respiratory system is false? a. The Hering-Breuer reflex inhibits inspiration. b. In the lung, Cl- enters erythrocytes in exchange for HCO3- which leaves erythrocytes. c. During expiration, the surface tension of the alveolar fluid increases. -ANS d. If pH decreases, PCO2 increases, or temperature increases, the amount of oxygen bound to hemoglobin decreases. e. Emphysema causes an increase in compliance of the lung. 10. The drawings below show lungs at the end of expiration (A) and at the end of inspiration (B) during quiet breathing.3 Indicate whether each of the following statements is likely to be true or false by writing the word “True” or “False” in the blank. Do not write T or F. ___________ a. In both A and B, alveolar pressure is zero, i.e., the same as atmospheric pressure. (T) ___________ b. In both A and B, intrapleural pressure is lower than atmospheric pressure. (T) ___________ c. In both A and B, transpulmonary pressure has a positive value. (T) 11. A 50-year old taxi driver was found in respiratory distress after an assailant punctured his chest with a knife. At the hospital, numerous tests were done. Here are some of the findings. - Chest radiographs showed 4 abnormalities: the right pleural cavity was filled with air, the right lung was collapsed, the spaces between the ribs were greater on the right side, and the density of the left pleural cavity was greater than normal. - Upon admission to the hospital, arterial PCO2 was elevated and arterial pH was 7.15 (normal is 7.35), but these values returned to normal after treatment. - After treatment and recovery, pulmonary function tests revealed that his ability to quickly and forcefully exhale was significantly impaired. - His medical history revealed that he has been a full-time taxi driver for 20 years and a heavy cigarette smoker for 30 years. Provide brief and concise answers to the following questions. a. In one word, what was the diagnosis upon admission to the hospital? Pneumothorax b. Why did the right lung collapse? ANS: The stab wound admitted air into the right intrapleural space, raising the normal negative pressure in that space to the level of atmospheric pressure. This reduced the transpulmonary (transmural) pressure to zero, and the right lung collapsed due to its natural