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Pathogens

Pathogens

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Description:

This lesson will give an overview of the body's three lines of defense against a pathogen.

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Tutorial

What's Covered

This lesson will look at pathogens and the three types of defenses the body has against them:

  1. Physical Barriers
  2. Innate Immunity
  3. Adaptive Immunity

1. Physical Barriers

Pathogens are any disease-causing agent and could be anything including fungi, bacteria, viruses, and, parasites. They are found almost everywhere and in order for our body to survive and not succumb to the attacks of these pathogens, it has to find ways to defend us against them.

Term to Know

    • Pathogen
    • Any disease-causing agent that we are exposed to (bacteria, virus, fungus, parasite, etc.

The body has three lines of defense against pathogens. The first line is the body’s physical barriers. The goal is to prevent pathogens from even entering the body at all, or, if they do enter, trying to immediately get rid of them.

ExampleMucosal linings, mucus, and our skin will prevent pathogens from entering the body.

Term to Know

    • Physical Barriers
    • Consists of skin and mucous membranes, physical barriers are our first line of defense against pathogens. Physical barriers are part of our non-specific immunity.

If they do get past, our body will try and get ride of them right away by:

  • Lysozyme, an enzyme, break down pathogens.
  • Diarrhea, a way which our body tries to flush out pathogens.
  • Good bacteria within our body will also try and get rid of those pathogens.

2.Innate Immunity

Innate immunity will activate if a pathogen gets past the physical and chemical barriers. Innate immunity is a generalized cure-all response; It's very nonspecific.It attempts to wipe out many invaders before they can even cause infection.

ExamplePhagocytes, inflammation, and fever.

Term to Know

    • Innate Immunity
    • Also known as non-specific immunity, innate immunity consists of general physiologic responses (fever, inflammation, etc.) that can affect the entire body.

Cells that are involved in innate immunity don't care what type of pathogen it is; they attack any type of pathogen.


3.Adaptive Immunity

Adaptive immunity is a much more specific type of immunity. This will also start when innate immunity starts, but there is a difference. Adaptive has specialized cells that fight specific pathogens. White blood cells that attack in adaptive immunity have specific receptors for specific types of pathogens. This type of immunity also changes throughout life as you encounter different sorts of illnesses by producing memory cells or immunity. This means that if you've had a certain type of illness once, your body remembers that illness and how to fight it.

Term to Know

    • Adaptive Immunity
    • Also known as specific immunity, adaptive immunity is carried out by T & B lymphocytes and reacts to specific antigens of cells; adaptive immunity also produces memory cells to target the same pathogen if we are ever exposed to it again.

Summary

Pathogens are any disease-causing agent, and your body has three lines of defense against them. Physical barriers that keep out pathogens in the first place or try to flush them out as soon as they enter. If a pathogen gets past this then the body’s innate immunity will kick it. This produces very generalized responses to fight pathogens. At the same time adaptive immunity will start. This type of immunity is carried out by white blood cells that target specific pathogens. This type of immunity also produces memory cells to fight a pathogen again in the future.

Keep up the learning and have a great day!

Source: Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND

TERMS TO KNOW
  • Pathogen

    Any disease-causing agent that we are exposed to (bacteria, virus, fungus, parasite, etc.)

  • Physical Barriers

    Consists of skin and mucous membranes, physical barriers are our first line of defense against pathogens. Physical barriers are part of our non-specific immunity.

  • Innate Immunity

    Also known as non-specific immunity, innate immunity consists of general physiologic responses (fever, inflammation, etc.) that can affect the entire body.

  • Adaptive Immunity

    Also known as specific immunity, adaptive immunity is carried out by T & B lymphocytes and reacts to specific antigens of cells; adaptive immunity also produces memory cells to target the same pathogen if we are ever exposed to it again.