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Question 315
Physiology → Haematology
Classification
Question
SSBAOptions
Explanation
erythrocytes move more slowly in capillaries than in venules because the total cross-sectional area of the capillary circulation is greater.
Option Validity
B) Mature erythrocytes obtain their energy through glycolysis, but does not attribute reduced capillary velocity to loss of energy production. The explanation given is the greater total capillary cross-sectional area.
C) does not state that haematocrit becomes zero in capillaries. Erythrocytes continue to traverse the capillary circulation.
D) Mature circulating erythrocytes are non-nucleated. Capillary transit does not cause them to acquire a nucleus.
E) Plasma clotting factors participate in coagulation but are not described as immobilising erythrocytes during normal capillary flow. The stated explanation is total cross-sectional area.
Further Reading
Saxena. Textbook for MRCOG-1. Physiology - Haematology - Red Blood Cells, p.67.