Part 2 in our understanding inflammation.
In episode 1, I briefly over viewed the typical acute inflammation symptoms. Any body part that becomes inflamed is usually given the suffix "itis". Tonsillitis is inflammation of the tonsils. Urethritis is inflammation of the urethra, cystitis is inflammation of the bladder (cyst=bladder), and Arthritis is inflammation of a joint (arthro= joint).
Spiderman to the rescue!!
So let's suppose an organism infects a site. Make it a tissue infection like a bacterial skin infection. A splinter while gardening, removed with tweezers and washed at the time of injury.
Yet bacteria got into the wound. Injured tissue releases chemicals from damaged epithelial cells inside tiny blood vessels. This chemical release of signalling chemicals is called chemotaxis. These chemicals are multiple types of proteins, and peptides that are collectively called cytokines (meaning cell attractors).
Cytokines like histamine and interleukin are secreted which causes the first in a cascade of white blood cells called Neutrophils to mobilise to the area of injury. Histamine causes vasodilation which increases blood flow to bring more neutrophils, and it forces capillaries to open their pores, allowing Neutrophils to migrate out of the blood vessel and into the site of tissue damage and bacteria.
Once at the scene of the "crime", neutrophils ingest bacteria, and dead cells. They are types of phagocytes meaning eating cells, but they also attack bacteria with chemicals that dissolve and digest their cell walls.
Finally, and most impressively, Neutrophils have the unique ability to weave spider web like nets that trap bacteria and kill them. Literally NETs , these Neutrophil Extracellular Traps (NETs) are fibrous strands of protein that is literally like a toxic spiderweb that serves as a physical barrier to wall off areas of infection. Very typical in skin infections like pimples, boils and abscesses. Neutrophils are just like SpiderMan spinning a web.
Superman follows
Clark Kent (AKA Superman) was a reporter. He could fight evil, but also report on it. And that is exactly what happens next.
Macrophages are another type of phagocyte that migrates to the area to assist neutrophils. They digest and mop up cellular debris, but in addition to the killing, they record information about the bacteria and having a taste of the bacteria (antigen), the the Macrophage reports a description to the Lymphocyte who then produces toxic killing and signalling chemicals called Antibodies (or Immunoglobulins).
And that is our next episode in the series on inflammation in "Knowing your Jargon".
Summary:
Spider-Man (neutrophils) first at the crime site. Kills bad guys, and sets NETs (traps).
Superman (Macrophage) is close second, kills more bad guys and tips off the media (Lymphocyte).
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