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Immune System
1.
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Identify 3 types of pathogens and identify ways that they enter your body.
Bacteria
- Mouth and nose
Fungi
are all pathogens
- Cuts and scrapes
are methods of entry
Viruses
- Eyes
Protists
2. Describe the difference between non-specific immune responses and specific immune
responses. Give and example of each.
-
Non-specific immune responses
First and second line of defence (skin,
tears, cilia, acids in stomach).
Reaction every time that you are
exposed to the pathogen.
Guards against all bacteria
Macrophages
Inflammatory response - Increased
blood flow and heat at the site of
infection
-
-
Specific immune responses
Primary component is the lymphocytes
(WBC).
Develop antibodies to the antigen
invader, the strongest reaction is after
the 1st time of exposure.
Knows certain invaders and guards
against them using T & B cells
3. Describe the first line of defence in your body.
First line of defence – Chemical & Physical non-specific defences.
 skin, mucus, cilia (nose hairs), eyelids, eye lashes, stomach acids and enzymes.
4. What is the role of the macrophage in the second line of defence in your body?
Macrophages have two roles: to release a chemical to dilate blood vessels and increase
blood flow and temperature and seek out and destroy foreign invaders by phagocytosis.
5. Describe the difference between an antigen and an antibody.
Antigen: ID tags on the outside of the cell membrane of the pathogen.
Antibodies: Proteins that protect the body from invaders by attaching themselves to the
antigens on the pathogens.
6. How do antibodies destroy antigens?
Antibodies are specific to certain antigens. They will only attach to those antigens and
upon attachment, this will disable the pathogen from spreading.
7. Compare and contrast macrophages and lymphocytes.
-
Macrophages
only engulf the invader via phagocytosis
push antigens to outside of their
membrane to be identified by helper T
cells.
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8. Compare and contrast T cells and B cells.
T Cells
- Made in the bone marrow
- Stored in the thymus gland
- Identify antigens on pathogens and call for
help.
- Killer T cells kill viruses
- Suppressor T cells stop the immune
response after battle
Lymphocytes
Identify invaders (by chemical
messages sent by helper T cells) & call
on B cells for help.
B cells produces antibodies to by
released into the bloodstream.
Memory B cells hang around to
remember the antigens of previous
invaders.
B Cells
- Made in bone marrow
- Stored in lymph nodes
- Memory B cells identify antigens found
previously.
- B cells make antibodies
9. Describe the function of the following cells in the body’s third line of defence.
- lymphocytes
- B cells
- suppressor T cells
- helper T cells
- killer T cells
- memory B cells
Lymphocytes: (WBC) white blood cells that produce antibodies.
B Cells: are produced and mature in the bone marrow. B cells are responsible for the production of
antibodies and memory cells.
Suppressor T Cells: Signal the immune system to shut down once the infection has been destroyed.
Helper T Cells: first cells to recognize the antigen on the macrophage. Helper T’s do three things: 1.
activate the killer T cells which search for invaders, 2. Have the body make more macrophages if required,
3. activate the B cells.
Killer T Cells: Attacks the infected cell, preventing the virus from reproducing (solider cells).
Memory B Cells: remain in the blood ready to trigger another immune response is the body is infected with
the same pathogen.
10. How do memory B cells provide immunity against further infections?
- They remember the antigens & circulate looking for them. They can kill those
pathogens quicker without the body showing symptoms.
11. Describe the difference between passive and active immunity.
- Passive immunity: occurs naturally as you are exposed to antigens throughout your life.
(e.g. breastmilk, exposure to antigens at pre-school etc).
-
Active immunity: medical intervention to acquire antibodies. (e.g. antibiotics for
illnesses, vaccines prior to travelling, immunization clinics specific to local pathogens).
12. What happens to the immune system with an autoimmune disease? An allergy?
Autoimmune diseases occur when your body mistakes healthy cells for foreign cells and fires
into the third line of defence for no specific reason. Children with autoimmune diseases
normally spend a lot of time in the hospital and must have special considerations made to keep
their environments free from pathogens. Examples of autoimmune diseases that can occur
include multiple sclerosis, rheumatoid arthritis, and lupus.
An allergy is an immune response to an antigen that is for a harmless material, like pollen or
dust mites. Your body goes into the third line of defence to attack the harmless material for
no reason. As a result you end up with flu like symptoms, runny nose, watery eyes, sneezing,
itchy skin etc. while your body is trying to combat the safe invader. To minimize an allergic
response, some people will take an allergy pill (anti-histamine), avoid exposure to the
pathogen, and in worse case scenarios will take an epi-pen job.