The following four videos introduce the immune system generally:
The above video provides a good place to start towards appreciating the very basics of immunology.
The above video presents immunity in an approximation of its insane complexity.
The above video serves as a general introduction to leukocytes, i.e., white blood cells.
The lymphatic system is crucial to the functioning of your immune system.
The rest of these videos focus instead (mostly) on innate immunity:
The above video provides an quick introduction to numerous aspects of innate immunity.
The above provides an overview of innate immunity.
The above video provides, using interesting graphics, a nice introduction into what the mucociliary transport is all about.
The above video discusses neutrophil functioning including terms of phagocytosis.
The above videos shows a pretty spectacular light microscopy movie of a neutrophil chasing and then engulfing a bacterium
The above video provides a nice, fairly comprehensive overview of acute, localized inflammatory responses. Note that the term, "Emigration" (leukocyte emigration), occurs via a process known as diapedesis.
The above video discusses inflammation and the role of macrophages in inflammatory responses as well as antigen presentation by macrophages; it ends with discussion of autoimmunity.
The above video discusses as well as distinguishes among monocytes, macrophages, and dendritic cells; it doesn't do a terribly good job of describing the associated antigen presentation, however.
This video covers a lot of ground, but does nonetheless do a good job of introducing what natural killer cells are all about. Note, though, that the depiction of a virus, starting at about 17 seconds, is completely wrong since bacteriophages, as shown, are viruses of bacteria rather than of our own cells.
The above video provides a nice illustration, without sound, of complement's classical pathway, stopping prior to "late" stages.
The above video describes the cellular morphology of eosinophils.
The above video describes the cellular morphology of basophils.
The above video provides an introduction to mast cells, with mention also of what are known as auxiliary cells.
The above video does a good job both describing what histamine is and its role in the body's allergic responses.
Truly everything you might ever want to know about fever.
The following video serves as a transition to the next chapter:
The above video provides a nice, if a bit complex, transition from discussions of innate immunity to ones of adaptive immunity, which of course represent simply two sides of a robust immune response.