Biology 1st Edition by Jerome Krueger, Kendra Hill, Robert Noyd

Exercise 12

The brain and spinal cord are nourished and cushioned by circulation of a fluid called cerebrospinal fluid. This fluid normally is sterile and flows between membrane layers surrounding the brain called meninges. However, in the disease meningitis, the cerebrospinal fluid becomes infected with pathogens, usually caused by either a viral or a bacterial infection. Knowing whether a virus or a bacterium causes meningitis is important because the severity of illness and the treatment differ. Which of the following components of the body's defenses would you expect to find in the cerebrospinal fluid if it is a bacterial infection? (a) macrophages, (b) killer T-cells, (c) B-cells, (d) antimicrobial proteins.