12. Bleeding from a small cut in the skin
A. Is normally diminished by local vascular spasm.
B. Ceases within about ﬁve minutes in normal people.
C. Is prolonged in severe factor VIII (antihaemophilic globulin) deﬁciency.
D. Is greater from warm skin than from cold skin.
E. Is reduced if the affected limb is elevated.
Answer to the question no 12
A. True. Due to the effects of tissue damage and serotonin on vascular smooth muscle.
B. True. This is the upper limit of the normal ‘bleeding time’.
C. False. Factor VIII increases clotting time, not bleeding time.
D. True. Warmth dilates skin blood vessels.
E. True. Intravascular pressure is reduced in an elevated limb.
A. Are protein molecules.
B. Are absent from the blood in early fetal life.
C. Are produced at a greater rate after a ﬁrst, than after a second, exposure to an antigen six weeks later.
D. Circulating as free immunoglobulins are produced by B lymphocytes.
E. With a 1 in 8 titre are more concentrated than ones with a 1 in 4 titre.
Answer to the question no 13
A. True. They are made by ribosomes in plasma cells.
B. True. Immunological tolerance prevents the fetus forming antibodies to its own proteins.
C. False. The response to the second exposure is greater since the immune system has been sensitized by the ﬁrst exposure.
D. True. T lymphocytes are responsible for cell-mediated immunity.
E. True. An antibody with a 1 in 8 titre is detected at greater dilution than one with a 1 in 4 titres.
14. Circulating red blood cells
A. Are about 1 percent nucleated.
B. May show an intracellular network pattern if appropriately stained.
C. Are distributed evenly across the blood stream in large blood vessels.
D. Travel at a slower velocity in venules than in capillaries.
E. Deform as they pass through the capillaries.
Answer to the question no 14
A. False. Nucleated red cells are not normally seen in peripheral blood.
B. True. Reticulocytes, the most immature circulating RBCs, show this pattern when stained with certain dyes.
C. False. They form an axial stream away from the vessel wall.
D. False. The capillary bed has a greater total cross-sectional area than the venular bed.
E. True. Normal cells, around 7 microns in diameter, become bullet-shaped as they pass
through 5-micron diameter capillaries.
A. Constitute 1–2 per cent of circulating white cells.
B. Are motile.
C. Can transform into plasma cells.
D. decrease in number following removal of the adult thymus gland.
E. Decrease in number during immunosuppressive drug therapy.
Answer to the question no 15
A. False. About 20 per cent of leukocytes are lymphocytes.
B. True. They migrate by the amoeboid movement to areas of chronic inflammation.
C. True. As plasma cells they manufacture humoral antibodies.
D. False. The thymus is atrophied and has little function in the adult.
E. True. Lymphocytes and immune responses are closely linked.