531. In urolithiasis
A. calcium is a major component of about 35% of calculi.
B. hypercalcaemia is found in most patients who make renal calculi.
C. presence of hypercalcaemia implies renal insufficiency.
D. struvite stones are made up of magnesium-ammonium-phosphate.
E. a patient with leukaemia is likely to make cystine calculi.

532. All of the following conditions are associated with polycythaemia EXCEPT
A. Leukaemia.
B. emphysema.
C. cyanotic heart disease.
D. renal cell carcinoma.
E. myeloproliferative disorders.

533. 13-Thalassemia
A. characteristically results from deletions in the f3-globin gene.
B. may involve an asymptomatic carrier state, with no demonstrable red cell abnormalities.
C. results in marked peripheral haemolysis requiring transfusion in the most severe cases.
D. is a major cause of hydrops foetalis and foetal death.
E. may result in iron overload and haemochromatosis.

534. In osteoarthritis
A. there is a marked synovial reaction.
B. chrondrocytes play a role in cartilage destruction.
C. osteophytes develop on top of the articular surface.
D. subchondral cysts are caused by collagenases.
E. cbrondrocytes excrete digestive enzymes into the matrix in active forms.

535. With regard to rheumatoid arthritis
A. in the joint it is confined to the synovium and does not involve the articular cartilage.
B. Xrays of joints reveal marginal erosions.
C. caseous necrosis is typical of rheumatoid nodules.
D. there is decreased vascularity in the pannus.
E. it is confined to joints and skin.

536. In bone fracture healing
A. woven bone forms in the periosteum and the medullary cavity.
B. osteoblasts lay down woven bone over the procallous to repair the fracture line.
C. PTH acts directly on osteoclasts to increase absorption.
D. haematoma at the fracture site plays little role in the formation of pro callous.
E. inadequate immobilization aids the formation of normal callus.

537. Which of the following can impair mucociliary action in the respiratory tract?
A. Smoking
B. Aspiration
C. Intubation
D. Viral infection
E. All of the above

538. Which of the following statements is INCORRECT?
A. Gastric acid, pancreatic enzyme & bile secretion are the 1 st line GIT defense against enveloped viruses
B. IgA antibodies form the 2nd line defense against ingested pathogens.
C. Antibiotics can alter normal bacterial flora in the GIT, and so weakened host defenses.
D. Mechanical obstruction or ileus can impair host GIT defense.
E. Antacids can impair host GIT defense.

539. Which of the following statements regarding intestinal pathogens is FALSE?
A. Vibrio Cholerae release enterotoxins in food, which causes secretory diarrhoea.
B. Salmonella typhi ulcerates gut mucosa to cause inflammation & haemorrhage.
C. Fungal GIT infection only occur in the immunosuppressed host.
D. Cysts of intestinal protozoa are resistant to gastric acid digestion.
E. Echinococcus passes through the gut briefly to access liver & lung.

540. Which of the following statements is TRUE?
A. Normal skin flora include bacteria, fungal species & some opportunistic species.
B. Low pH & fatty acid content of skin layer favours commensal bacteria over bacterial pathogens.
C. Any breach of skin integrity is a potential portal of pathogen entry.
D. Heat & moisture can weaken skin resistence to pathogens.
E. All of the above.