How does the immune system of vertebrates utilize a chemical concentration gradient?
A) The immune system produces thousands of histamines that act solely to create a histamine diffusion barrier.
B) The immune system generates a gradient of reactive oxygen intermediates to increase the amount of toxic radicals and peroxides to combat invading pathogens.
C) The immune system releases chemical signals called chemokines, which create a chemical gradient that leukocytes use in migrating toward the infection site.
D) The vertebrate immune system does not use chemical gradients.
Answer: C
You might also like to view...
Which of the following is NOT a characteristic of seeds?
A. They contain endosperm. B. They have an embryo. C. They may differ in amount of water content. D. They usually vary in size. E. They usually have about the same amount of water.
Plants that are adapted to growing in flooded soils that are depleted of oxygen have:a
aerial roots. b. contractile roots. c. pneumatophores.
d. prop roots. e. buttress roots
The cortical reaction of sea urchin eggs functions directly in _____
A) the formation of a fertilization envelope B) the production of a fast block to polyspermy C) the release of hydrolytic enzymes from the sperm D) the generation of an electrical impulse by the egg
A person may have a muscle injury that really affects the tendon and not the muscle tissue itself. Why is it that after a hard workout, muscle pain will go away in a few days at most, but tendinitis lasts so much longer?
A) The electrical signals that muscle cells generate are used to aid in healing. B) Muscle cells can be rested, but tendons have to be used all the time. C) Unlike a tendon, muscle tissue has an ample blood supply, so it's easier to repair. D) Muscle cells are more elastic, so they are harder to damage.