Defending The Body Quiz (PHYSIO)

Innate Immune System

Our more primitive this is:

• Preventative

  • Quick to respond (if something does happen)’

  • Stops you from getting sick in the first place

  • General (non-specific)

  • solid at everything, great at nothing, because it doesn’t actually cure you

Barriers

The body's first line of defense in the immune system. They consist of physical, chemical, and biological mechanisms that block pathogens (like bacteria and viruses) from entering and causing infection

Skin (Barrier)

• Impermeable to most pathogens

• Ability to prevent bacteria and pathogens to attack us

• Constant shedding removes surface pathogens

• Always bacteria on here

• Lack of moisture, blood, and sebum (oil) provides a bad environment for pathogens, so that prevents stuff from getting there and living there

Tears/Sweat/Saliva (Barrier)

• Contain lysozymes (antimicrobial enzymes found in human secretions that act as a natural defense system)

Respiratory/Digestive Systems (Barrier)

• Lined with mucous membranes that trap pathogens

• Lined with cilia that catch pathogens

• Coughs can be used to expel pathogens

• Eats the bacteria then breathe them

• Blood-Brain Barrier prevents pathogens from getting into the cerebrospinal fluid/brain, extra layer of defense

Non Specific Mechanisms

The body’s built-in, generalized defenses. They act as the second line of defense, responding immediately or within hours to all foreign invaders in the exact same way, without targeting any specific pathogen. When pathogens get in, they fight the pathogens but not designed to fight the pathogens

Inflammation (Non-Specific Mechanisms)

• Cell that are initially “injured” release a bunch of chemicals like histamines and cytokines

• These chemicals dilate vessels, attract all kinds of WBCs, and cause swelling to block off the area

• The goal is to kill pathogens, clear the area, and begin healing

• Signs/symptoms include redness, itching, heat, and/or pain/irritation

• Shows us not to touch or do anything to the infected area

Fevers (Non-Specific Mechanisms)

• Increased temperature can kill pathogens (and you, since we can’t live with high temperatures)

• Increased temperature speeds the activity of some white blood cells

• hope that we survive from this so this mechanism does its work

Miscellaneous (Non-Specific Mechanisms)

• Gut bacteria fight off other pathogens, because they are territorial

• Stomach acid can be used to kill pathogens

• Urination can kill and cleanse pathogens in the urethra

Innate Substances and Cells

The body's inborn, main, last resort, line of defense. It acts immediately and non-specifically to destroy foreign invaders, responding the same way to all threats without retaining memory of them

Interferons (Innate Substances/Cells)

• Released when one of our own cells is infected by the pathogen/virus, it:

• tells nearby cells to increase their defenses (like an alarm)

• Activates other immune cells

Opsonins (Innate Substances/Cells)

• Attach themselves to pathogens and “tag” them to be phagocytized.

• Proteins that act as biological "tags" by coating foreign pathogens (like bacteria or viruses), dead cells, or cellular debris. By binding to these targets, they enable immune cells called phagocytes (such as macrophages and neutrophils) to recognize, ingest, and destroy them

Natural Killer Cells (Innate Substances/Cells)

• type of lymphocyte that can attack infected cells with no activation or “presentation”

• Acting as the body's rapid-response security, they patrol for virus-infected or cancerous cells and destroy them without requiring prior activation or exposure to the pathogen

• Good to have more so we don’t get sick often

Macrophages (Innate Substances/Cells)

•  Large phagocytic cells that are “everywhere” and help with inflammation and defense

• Macrophages are specialized, versatile white blood cells that act as the body’s primary cleanup crew and first-line defenders.

Acquired Immune System

Our more advanced immune system:

• Enhances the existing immune response, gives an extra punch to the other immune system

• Is highly specific, leads to fighting the right tools for the specific thing

• Requires exposure to pathogens, and thus is slow to respond (4-7+ days)
  

Antigen

• “All” cells have this on their membranes that act as their “identification”

• The acquired immune system must identify the specific this on the pathogen in order to find the specific immune cells that will work

Antigen Presentations

The acquired immune system will identify the antigens of the pathogen in one of three ways:

• By just coming across the pathogen and “seeing it”

• A macrophage will engulf a pathogen and then “present” it to a variety of immune cells

• Infected cells (host cells) can present themselves/the pathogen antigen to show the infection so that other cells can fight them

B Cells

Have antibodies on their membranes that are DNA based

• Meaning there can be an infinite variety of antibodies

Start as naive. They patrol but have never met a pathogen before

If they happens to find its pathogen/antigen, they well make many copies, then will divide into:

• Plasma cells

• Memory B cells

Memory B cells

Will “remember” that pathogen and will be called upon quickly if the same pathogen is encountered again

Plasma cells

Are able to secrete their antibodies in an effort to hunt down the pathogens, release loads of antibodies to attack those pathogens. Antibodies will clump, lysis, block, or mark pathogens

T cells

Naïve Cells 

• Patrol around and have never “done anything” before, until finds the pathogens and makes copies of the right cells to hunt down what’s making us sick

• Can only bind to antigens that have been presented

• When done, these cells will divide into a variety of different types.

Killer T cells/Cytotoxic T cells

directly lyse/fight infected cells, cancer cells, and free floating pathogens

Helper T cells

release chemicals that activate other cells

Regulatory T cells

helps to maintain the body’s ability to identify “self” from “non-self” 

Memory T cells

Will “remember” that pathogen and will be called upon quickly if the same pathogen is encountered again (like B cell)