Scanning electron micrograph of two rod-shaped bacilli of Klebsiella pneumoniae (colorized red), which can cause pneumonia and bloodstream infections. (Credit: David Dorward/National Institute of Allergy and Infectious Diseases)
Scanning electron micrograph of spheroid-shaped methicillin-resistant Staphylococcus aureus (MRSA) bacteria (colorized yellow) surrounded by cellular debris (colorized orange). (Credit: National Institute of Allergy and Infectious Diseases)
Mast cell activation. (a) Multiple stimuli can activate mast cells. (b) Activated mast cells produce mediators and proteins that can influence the outcome of an immune response or its associated tissue changes.
Tripneustes ventricosus (Lamarck), tropical eastern and western Atlantic, found at depths of 0–55 m (0–180 ft). (From G. Hendler et al., Sea Stars, Sea Urchins and Allies: Echinoderms of Florida and the Caribbean, Smithsonian Press, Washington, DC,…
A pyramid from Aristotle's lantern, showing epiphyses joined and tooth with keel. (After H. L. Hawkins, The lantern and girdle of some Recent and fossil Echinoidea, Philos. Trans. R. Soc. Lond. Ser. B, 223:617–649, 1934)