Immunology I Flashcards
Where is the immune system located?
It is scattered throughout the whole body and is connected by blood and lymph.
What is the role of the immune system? Describe two situations where it is necessary.
Its role is to protect the body. It can protect from pathogens, such as bacteria, viruses, and parasites, and from altered body cells, such as cancer.
Describe two situations in which the immune system can “turn on us”.
- In the case of autoimmune disorders, where it identifies the body’s cells as foreign and attacks them
- When it attacks foreign tissue after a transplant or graft.
What are the two components of the immune system?
Non-specific/innate immunity and specific/adaptive immunity.
Of the two major components of the immune system, we are born with […]
Both
Name two differences between innate immunity and adaptive immunity.
Innate immunity does not recognize the specific pathogen it is fighting and responds the same way each time it sees the pathogen. On the other hand, adaptive immunity requires the recognition of the pathogen and responds faster when it sees the same pathogen again.
Explain the origin of vaccination
Smallpox disease led to lesions, which left behind scars called “pox”. Dr. Edward Jenner noticed that no milkmaids, who had gotten cowpox, had the marks of smallpox, leading him to assume that one protected the individual from the other. He took pus from a smallpox pustule and put it other the skin of another individual to inoculate them against smallpox and it worked.
What are the two categories of lymphoid organs? Explain the difference between them.
Primary lymphoid organs: sites where stem cells divide and immune cells develop
Secondary lymphoid organs: sites where most immune responses occur
Immune cells are also known as..
Leukocytes
Name the two primary lymphoid organs.
The bone marrow (yolk sac and fetal liver in embryo) and the thymus
What is the immune function of the bone marrow?
It is where B and T cells are first produced and where B cells reach maturity.
What is the bursa and what is it homologous to in humans?
The bursa is an organ in the chicken that allows for the production of B cells. It is homologous to the bone marrow.
What is the immune function of the thymus?
It is where T cells mature. It also contains T cells, scattered dendritic cells, epithelial cells, and macrophages.
What happens to the thymus as we age?
it shrinks and eventually disappears.
Name the three secondary lymphoid organs.
Lymph nodes, spleen, and lymphoid nodules
Where are lymph nodes found?
Scattered throughout the body
What is the immune function of lymph nodes?
To filter microbes and phagocytose microbes that enter with macrophages. This prevents them from entering the circulatory system and causing harm.
What is the immune function of the spleen?
It removes microbes and dead/old erythrocytes. It is also the largest lymphoid organ.
What is the immune function of lymphoid nodules?
They serve the same function as the lymph nodes but are located at specific sites in the body that are in contact with the outside world.
Give 3 examples of lymphoid nodules.
Tonsils, peyer’s patches and MALT, appendix
What are the two major categories of leukocytes?
There are lymphocytes and those produced from the myeloid pathway.
Name the 3 major types of lymphocytes.
T cells, B cells, NK cells
Where do each of the 3 lymphocyte types mature?
B cells and NK cells: the bone marrow
T cells: the thymus
Name the three types of T cells and the indicators of each one.
Cytotoxic T cells (CD8+), helper T cells (CD4+), regulatory T cells (CD4+)
Myeloid leukocytes are divided into two major categories, […] and […]
Granulocytes and monocytes
Name all the granulocytes and their function.
Neutrophils: phagocytes, release vasodilators during inflammation
Eosinophils: destroy parasites
Basophils: release chemicals like histamine and prostaglandin
Mast cells: release chemicals like histamine
Name all the monocytes and their function.
Macrophages
Dendritic cells (professional antigen presenting cells)
In innate immunity, what qualifies as the first and second line of defense?
First line of defense: physical barriers
Second line of defense: cellular factors and humoral factors (dissolved in fluids, will fight infection)
Explain the first line of defense in innate immunity.
It consists of physical barriers that make for unpleasant living conditions for microorganisms.
Name 5 physical barriers leading to innate immunity in the skin.
Epithelial cells joined by tight junctions
Longitudinal flow of air or fluid
Fatty acids
Antibacterial peptides
Normal flora (microbiome)
Name 6 physical barriers leading to innate immunity in the gut.
Epithelial cells joined by tight junctions
Longitudinal flow of air or fluid
Low pH
Enzymes such as pepsin
Antibacterial peptides
Normal flora (microbiome)
Name 3 physical barriers leading to innate immunity in the lungs.
Epithelial cells joined by tight junctions
Movement of mucus by cilia
Antibacterial peptides
Name 3 physical barriers leading to innate immunity in the eyes and nose.
Epithelial cells joined by tight junctions
Salivary enzymes (lysozymes)
When is the second line of defense in innate immunity needed?
When bacteria has overcome the first line of defense (physical) and has managed to enter the body.
Name 3 humoral factors in the second line of defense.
Inflammation and fever
Antimicrobial substances
Interferons
Name 3 cellular factors in the second line of defense.
Phagocytic cells
Cells with inflammatory mediators (basophils, mast cells, eosinophils)
NK cells
What are the 4 distinct signs and symptoms fo inflammation?
Redness, heat, pain, and swelling
What are the 3 stages of inflammation?
- Vasodilation: widening of blood vessels, allowing more blood flow to the site
- Emigration of phagocytes
- Tissue repair
Give 3 examples of humoral antimicrobial substances.
C-reactive proteins (viral proteins), complement, and iron-binding proteins.
Explain the function of interferons in the immune system.
When a body cell becomes infected with a virus (protein capsid with genetic material that takes over the cell’s ability to produce its own components), the viral infection is fought with Type 1 interferons, which are secreted by the cell when it recognizes the virus. Other cells have receptors for Type 1 interferons, so they can produce antiviral proteins in anticipation of the virus’ arrival.
What is a complement?
It is a large family of plasma proteins with multiple functions.
Name the two main complement pathways and whether they belong to innate immunity or adaptive immunity.
There is the classical pathway, which is part of adaptive immunity, and the alternative pathway, which is part of innate immunity.
Explain how the alternative complement pathway works in innate immunity.
The complement protein sticks to the pathogen, covering its surface through a process called opsonization. This makes the bacteria easier to be phagocytized.
Explain the function of complement C3b as an opsonin.
Phagocytes have a C3b receptor on their surface. So the activated complement, C3b, sticks to the bacteria at the site of infection to increase the phagocytosis of the bacteria.
Note that C3b is floating through the plasma waiting to be used.
Given an example a humoral substance that is an iron-binding protein and explain its function.
Transferrin. The function of iron-binding proteins is to sequester as much iron as possible, because iron is critical for the survival of a bacterial infection.
Iron-binding proteins are produced by the […]
Liver
Give 2 examples of autoimmune diseases.
AIDS (acquired immuno-deficiency disorder) and SCID (severe combined immune disorder)
AIDS affects the immune system by […]
Killing T helper cells
SCID affects the immune system by […]
Leaving the individual without bone marrow and lymph
