How does the inflammation process in our bodies work? What are the steps and why does this happen?


How does the inflammation process in our bodies work? What are the steps and why does this happen?

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Your immune system sends out its first responders: inflammatory cells and cytokines (substances that stimulate more inflammatory cells). These cells begin an inflammatory response to trap bacteria and other offending agents or start healing injured tissue. The result can be pain, swelling, bruising or redness.

This is a hugely broad question with a complicated and incomplete answer, but *very* generally speaking:

Inflammation is a state of heightened alert that enhances immune functioning at the cost of disrupting most normal functioning.

It generally requires some stimulus to get started, which can be signs of pathogen presence (like LPS from bacteria), signs of damage/distress to other host cells (like free-floating DNA, which is “supposed” to stay inside cells unless they die in uncontrolled ways), or proinflammatory signaling within the host (TNF is a very well known factor in this). The latter you can think of as signal amplification; you go on alert because the guy next to you does too, or because some other signal tells you to, in the absence of knowing/detecting the cause yourself.

While in a state of inflammation, tissue becomes more accessible for various cells of the immune system and soluble factors like antibodies and complement. It also makes those cells more aggressive about their decision making (not actual conscious decisions of course, but more like chemical balances), gears up their metabolism to enable greater mobility/protein synthesis/etc, and generally improves their ability to deal with pathogens.

Inflammation generally resolves when the “original” reasons for it are dealt with, leading to fewer pro-inflammatory signals being present anti-inflammatory signals tipping the balance back.

Inflammation is the first response of the immune system to any injury/infection and is the first pathologic process (meaning – related to disease progression). So from a small injury to fever to appendicitis, all go through inflammation first.

Now there are chemical compounds called pathogens (molecules that cause disease) Usually the process goes like this : bacteria/virus/microorganisms enter our body, body/immune system detects certain proteins and chemical structures on them (like the cell wall,etc), sends a signal to the brain, brain is like oops need to kill that, need more ammo, so they release some other substances/chemical compounds which further activates the immune system.

Now there are basically 2 overall changes that happen during inflammation but very broadly and generally-

1) blood/blood vessel related changes (vascular)-

which means the blood vessels broaden —- more blood reaches that area —— more warmth in that area

and blood becomes more thick and slows down (stasis)

2) cell (which are present in the blood) – related changes –

blood vessels can have various gaps through which cells and other stuff can pass if need be, during inflammation these gaps become active and increase in number (called increased permeability) which results in loss of fluid (plasma) from the vessel into the tissue resulting in swelling.

due to this and stasis(from above), the white blood cells (immune system cells that fight the causative agent) leak out of the blood vessel and reach the site of injury via following a trail of certain chemicals (chemotaxis) and attack the problematic things

This is a VERY broad and generalised explanation and every step has further sub steps involved includinh the actual process of ‘fighting’ but it’s ELI5 so I’ll stop here for now.

Hope this helps. Feel free to ask any questions 🙂