Defending Your Body

To defend against invaders—bacteria, viruses, and other pathogens—our bodies have two levels of defense.

  1. Nonspecific defense mechanisms
  2. Specific defense mechanisms (a.k.a. the immune system)

Nonspecific Defense Mechanisms

1. Barriers

Shows various barriers that impede pathogens' access to the body.

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2. Internal Defenses

2.1 Leukocytes


Gives an electron-microscope view of a macrophage. Shows a macrophage attacking bacteria in the presence of a red blood cell.

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Natural Killer Cells (NK cells)

Shows a colorized view of cancer cell being surrounded by a number of natural killer cells.

Part of an unlabeled figure, page 840, Campbell's Biology, 5th Edition

2.2 Antimicrobial Proteins

Two different antimicrobial protein systems exist:

Shows the role of complement proteins in helping to lyse the cell membrane of microbes.

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2.3 The Inflammatory Response

Shows the different participants and steps in the inflammatory response.

Figure 18.4, Purves's Life: The Science of Biology, 7th Edition

Cell Potency

Derivation of all Blood Cells: The Pluripotent Hematopoietic Cell

Categories of Blood Cells

Shows all of the cells derived from the bone marrow's pluripotent hematopoietic cell, including their relationships and categories.

Figure 18.2, Purves's Life: The Science of Biology, 7th Edition