4. X-linked hyper IgM syndrome, resulting in high levels of serum IgM and low levels of serum IgG, is caused by a defect in CD40L expression. The specific immune event that would be prevented by a defective CD40L would be
Options
A. activation of B cells by T-independent antigens
B. failure of B cells to provide co-stimulation for Th2 activation
C. failure of Th2 cells to provide co-stimulation for B cell isotype switching
D. failure of Th2 cells to provide co-stimulation for B cell proliferation
Correct Answer: Insulin; many different cell types that use glucose for fuel
9. If a disease of the blood vessels caused the endothelial cells of the vessel to die, what effect would that have on the cellular activities associated with vasodilation?
Options
A. Nitric oxide would no longer be produced
B. Smooth muscle cells could not be made to relax
C. It would be more difficult to increase blood flow and reduce blood pressure