Exam 3 | Immune & Lymphatic

Question 1

What does the immune system do?

Answer 1

The immune system is responsible for protecting the body from foreign agents (pathogens) by launching an internal immune response when foreign entities are detected. A similar response is also initiated after physical (internal or external) injury, and contributes to the symptoms of allergies and autoimmune diseases.

Question 2

What does the lymphatic system do?

Answer 2

The lymphatic system supports the immune system by circulating lymph fluid through specialized vessels and lymph nodes, where several immune cells are formed

Question 3

What structures are a part of the lymphatic system?

Answer 3

The thymus, spleen, and tonsils are all specialized structures that are considered to be part of the lymphatic system, as well as (red) bone marrow, skin, and internal mucous membranes such as those in the nasopharynx.

Question 4

What are pathogens?

Answer 4

Foreign invaders that can cause infection and/ or disease once they enter the body are collectively known as pathogens.

Question 5

What are the 6 different types of pathogens?

Answer 5

There are 4 that are considered living/cellular (organic):
Parasites
Protozoa
Fungi
Prokaryotes

There are 2 that are considered nonliving/acellular (inorganic):
Virus
Prion

Question 6

What are parasites?

Answer 6

Parasites are the largest of all pathogens shown here; can cause serious problems like tapeworm. Live inside host and consume nutrients from host. Rare in developed parts of the world, from contaminated food/water

Question 7

What are protozoa?

Answer 7

Malaria is from a mosquito that’s infected by a protozoa. Protozoa infects mosquito and lives inside it so when the mosquito bites a person, we get infected.

Question 8

What are fungi?

Answer 8

Fungi can be drug resistant which has been causing a lot of problems. Athlete’s food is a common problem due to the dark, wet environment

Question 9

What are prokaryotes?

Answer 9

Bacteria; common example is leprosy

Question 10

What’s a virus?

Answer 10

Viruses are a problem considering they can effect humans from animals; common example is AIDS

Question 11

What’s a prion?

Answer 11

Prions are misfolded proteins that when coming into contact with other proteins in the body, it causes them to misfold as well. We have no way to fight against prion based diseases. CJD (mad cow disease) causes very serious cognitive decline and neurological problems

Question 12

What are other exogenous triggers that can cause an immune response?

Answer 12

Physical injuries (internally or externally) & allergens

Question 13

How do injuries trigger an immune response?

Answer 13

Injuries typically trigger the first line of defense in the immune response, resulting in what is known as an inflammatory response

(sometimes also referred to as an “inflammatory soup”, due to the plethora of signaling molecules released as part of this inflammatory response).

Question 14

How do allergens trigger an immune response?

Answer 14

Allergens, which are not considered to be pathogens as they do not typically cause infection or disease upon entering the body, but are nevertheless interpreted as “foreign” by immune cells and targeted with an immune response that is typically associated with an increased release of the chemical histamine.

As with the inflammatory response, release of histamine results in increased local inflammation.

Question 15

How do autoimmune diseases impact our immune response?

Answer 15

An endogenous trigger of the immune response is observed in autoimmune disorders, an example of which we discussed in the first quarter of the course (rheumatoid arthritis).

A hallmark of autoimmune disorders is a triggering of the immune response due to normal, endogenous cellular activity, which can often lead to inflammation and a cascade of other physiological effects. Body often attacks its own cells as if they were foreign

Question 16

What are the two classes of immune cells and what progenitor cell do they derive from?

Answer 16

Lymphocytes originate from lymphoid stem cell. They are closely associated with (produced in) structures of the lymphatic system.

Granulocytes originate from myeloid progenitor. They’re hite blood cells that contain a specialized organelle known as a granule in their cytoplasm. These granules typically carry enzymes that allow these cells to destroy and digest foreign invaders.

Question 17

What are the three levels, or “lines” of defense in the mature human immune system?

Answer 17

The first level of defense is the most general in its targeting behavior, and relies primarily on the skin and other epithelial tissue to provide a physical barrier protecting the internal organs and cells from injury or pathogenic invasion. In most cases, physical injuries only require this level of defense in order to protect the body from further harm.

The second level of defense is known as the innate immune system, and relies primarily on granulocyte activity (with some lymphocyte activity, specifically from Natural Killer Cells). This form of immunity is also relatively nonspecific, in terms of targeting behavior, but is more robust than the inflammatory response associated with the first level of immunity.

The third level of defense is known as the adaptive immune system, and relies primarily on lymphocyte activity, with granulocytes still playing an essential role. This immune response is the most specific in its targeting of pathogens, and the cornerstone of this response are the antibodies produced to bind specific antigens.

Question 18

What is the innate immune system?

Answer 18

It is the second line of defense in the body, and relies on pre-existing granulocytes and nonspecific antibodies to target foreign invaders that escape the first line of defense (the skin).

In particular, neutrophils, macrophages, dendritic cells and natural killer cells are the first to respond to, detect and destroy pathogens, with the assistance of natural (nonspecific) antibodies capable of binding multiple different types of antigens.

This immune response is typically rapid and immediate, taking place over the course of several hours.

Question 19

What is the adaptive immune system?

Answer 19

It is the third line of defense in the body, and relies on pre-existing (and newly-formed) lymphocytes (B & T cells) and specific antibodies to target foreign invaders that escape the second line of defense.

As a result, this immune response is much more prolonged, taking place over the course of several days.

Question 20

What is the essential protein that aids both innate and adaptive immune system?

Answer 20

antibodies

Question 21

What are antibodies?

Answer 21

Antibodies are unique proteins that typically bind to a specific molecule, or antigen and recruit other immune cells (often lymphocytes) to attack the antigen or pathogen from which the antigen originated

Question 22

Why are antibodies important?

Answer 22

Endogenously, antibodies are essential for an immune response to occur, and are often the “initial detectors” of foreign invaders.

Exogenously, the specific binding behavior that is a hallmark of antibodies makes them excellent tools for molecular visualization through techniques such as immunocyto- and immunohistochemistry.

Question 23

What are antibodies referred to and what makes their structure unique?

Answer 23

Antibodies are also referred to as immunoglobulins.

Most antibodies actually have a characteristic “Y-shape” to them, with the internal secondary and tertiary structures creating the heavy chains of the antibody, while the external secondary and tertiary structures comprise the light chains.

Question 24

What are the 5 classes of antibodies?

Answer 24

IgG, IgM, IgA, IgD, IgE

Question 25

What is Immunoglobulin G (IgG)?

Answer 25

It is the largest class of antibody with the highest opsonization and neutralization activity (meaning that they are most effective at targeting and destroying antigens). They typically circulate throughout the body via the lymphatic vessels.

Question 26

What is Immunoglobulin M (IgM)?

Answer 26

Immunoglobulin M (IgM) is the antibody typically activated first upon infection, and increases in quantity throughout the course of an immune response. As with IgGs, these antibodies typically circulate throughout the body via the lymphatic vessels.

Question 27

What is Immunoglobulin A (IgA)?

Answer 27

Immunoglobulin A (IgA) is exclusively expressed/ found in mucosal tissues, particularly in the digestive tract. These antibodies form dimers (or molecular “pairs”) once secreted.

Question 28

What is Immunoglobulin D (IgD)?

Answer 28

Immunoglobulin D (IgD) is the least understood of the five immunoglobulins, in terms of its function. It has been detected in lymphatic fluid circulating throughout the body.

Question 29

What is Immunoglobulin E (IgE)?

Answer 29

Immunoglobulin E (IgE) is the antibody most closely associated with the allergic response, and as with IgGs, IgMs and IgDs, this antibody circulates throughout the body via the lymphatic vessels.

Question 30

What are antibiotics?

Answer 30

Antibiotics are a form of treatment that can be used to treat bacterial infections only.

Antibiotics are not only ineffective at treating other pathogen-borne infections (including viral infections), they can actually be quite harmful to the endogenous bacterial populations in the body and to the function of specific organs (notably the liver, which is responsible for processing all drugs), and thus, use of antibiotics should be limited to confirmed cases of bacterial infections.

Question 31

What are antivirals?

Answer 31

Antivirals are pharmacological treatments that can be used ward off a viral infection after an individual has been infected and presents symptoms.

As with antibiotics, antivirals are specific to treatment viral infections, and often, one antiviral cannot be used to treat multiple different kinds of viral infections. Also similar to antibiotics, antiviral drugs can be hard on the body, and thus, are typically only used in cases of severe viral infections in which other treatments have not been effective.

Question 32

What are inoculations (vaccines)?

Answer 32

Inoculations (Vaccines) are a prophylactic method for building up an individual’s adaptive immune response to a particular pathogen, and can only be administered before an individual has been infected with a specific pathogen.

Traditionally, vaccines have been developed from neutralized remnants of the pathogen the vaccine is designed to immunize against, however, more recent developments in mRNA vaccine technology have made it possible to inoculate against a pathogen (virus) using an excerpt from the viral genome, which is typically RNA-based.

Question 33

How is bacteria becoming antibiotic resistant from humans?

Answer 33

More recent over-prescription of antibiotics, in conjunction with patients not completing the full course of the antibiotic treatments prescribed, have led to a steep increase in the number of resistant bacteria that are capable of dodging these antibiotic treatments and thus, causing more severe infections and disease.

Question 34

How does bacteria evolve to become resistance to antibiotics?

Answer 34

Bacteria have evolved to avoid being destroyed by common antibiotic treatments because of plasmids. Bacterial DNA is circular in shape, and typically accompanied by small DNA loops known as plasmids. Bacteria often acquire these plasmids through reproduction and by encountering new cells and viruses.

Question 35

How do mRNA-based vaccines work?

Answer 35

In the case of the COVID-19 mRNA vaccines, the mRNA codes for the spike protein, which is the protein expressed on the outer shell of the Sars-CoV2 virus that allows the virus to effectively invade a host organism’s cells and infect them. Normal cells in the body are essentially given a “sneak preview” of what this spike protein looks like, and its binding behavior, by creating the spike protein in isolation and “studying it” via the adaptive immune response. This way, if the individual does encounter the spike protein attached to the entire Sars-CoV2 virus, the body will already have developed antibodies capable of binding specifically to this spike protein and can prevent infection and development of the disease known as COVID-19.

Question 36

What’s the correlation between mRNA-based vaccines and adaptive immunity?

Answer 36

Studies have shown that mRNA-based vaccines have the potential to confer stronger (adaptive) immunity against a specific virus, and do not require neutralizing the entire virus (or even injecting the live virus into a patient) to trigger this adaptive immune response.