Question 1

A newborn infant may have some immune defense because of the presence of IgA antibodies in its blood. What is the source of these antibodies?

Accepted Answer

IgA antibodies are primarily transferred to the newborn through colostrum and breast milk, not through the placenta. This provides the infant with passive immunity from the mother.

Question 2

Some lymphocyte precursors become B cells after being processed within the __________. Others become T cells after being processed within the __________.

Accepted Answer

Lymphocyte precursors become B cells within the bone marrow and T cells after being processed within the thymus.

Question 3

The activation of what type of immune cell requires that an antigen be "presented" to it by an antigen-presenting cell?

Accepted Answer

T cells require that an antigen be presented to them by an antigen-presenting cell (APC) such as a dendritic cell, macrophage, or B cell. This process involves the presentation of the antigen in the context of major histocompatibility complex (MHC) molecules.

Question 4

Activation of complement proteins results in several effects, including opsonization. What is opsonization?

Accepted Answer

Opsonization refers to the process where complement proteins coat the surface of pathogens, such as bacteria, making them more recognizable and easier to be engulfed and destroyed by phagocytes like macrophages and neutrophils. This enhances the phagocytosis of antigens.

Question 5

A small molecule called a(n) __________ that on its own cannot stimulate an immune response, might become detectable to the immune cells once it combines with a larger molecule.

Accepted Answer

Haptens are small molecules that, when combined with larger molecules, can elicit an immune response by becoming detectable to the immune system. They cannot stimulate an immune response on their own.

Question 6

What factor leads to the formation of lymph?

Accepted Answer

Increased hydrostatic pressure in tissue fluid pushes fluid out of blood vessels and into the surrounding tissues. Some of this fluid is then collected by the lymphatic system, becoming lymph. This process helps to maintain fluid balance in the body by returning excess tissue fluid back to the bloodstream.

Question 7

What is lymph?

Accepted Answer

Lymph is the fluid that circulates within the lymphatic vessels, carrying cells and substances throughout the lymphatic system.

Question 8

In a healthy individual, IgA is typically most abundant in what fluids?

Accepted Answer

IgA is most abundant in exocrine secretions, including saliva, tears, and secretions from the respiratory and gastrointestinal tracts, playing a crucial role in mucosal immunity.

Question 9

What type of immunity develops in response to contracting an infectious disease?

Accepted Answer

Naturally acquired active immunity develops when a person is exposed to a live pathogen, contracts the disease, and then recovers from it, during which the immune system produces antibodies and memory cells specific to that pathogen.

Question 10

Carl has frequent infections and, after testing, has been diagnosed with a genetic form of agammaglobulinemia (meaning no gamma globulins in the blood). Why would this condition result in difficulty fighting off infections?

Accepted Answer

Agammaglobulinemia affects B cells' ability to produce antibodies, crucial for the humoral immune response that targets pathogens in body fluids. Without these antibodies, the body struggles to fight off infections.

Question 11

Allison has severe hay fever. What is the mechanism for her hypersensitivity?

Accepted Answer

The mechanism for Allison's hay fever, a type of allergic reaction, involves IgE antibodies that are bound to mast cells. When these antibodies bind an allergen, histamine and other mediators are released, leading to the symptoms of hay fever. This is a classic example of Type I hypersensitivity reaction.

Question 12

After being bit by a poisonous snake, Jacob was treated with an injection of an antiserum produced by immunizing a horse or sheep with snake venom. What type of immunity does this provide for him?

Accepted Answer

This is an example of artificially acquired passive immunity, where pre-made antibodies are introduced into the body. In this case, the antiserum from an immunized animal provides immediate protection but does not lead to long-term immunity because the recipient's immune system is not involved in producing these antibodies.

Question 13

What classes of antibodies are involved in activation of complement?

Accepted Answer

IgG and IgM are the two classes of antibodies that can activate the complement system, which plays a crucial role in the immune response by enhancing the ability of antibodies and phagocytic cells to clear pathogens.

Question 14

What is the cytolytic substance released by NK cells that lyse the cell membranes of infected or cancerous cells?

Accepted Answer

Perforin is the cytolytic substance released by NK (Natural Killer) cells that creates pores in the cell membranes of infected or cancerous cells, leading to their lysis.

Question 15

What is an example of an autoimmune disease?

Accepted Answer

Systemic lupus erythematosus is an autoimmune disease where the immune system attacks its own tissues, causing widespread inflammation and tissue damage in the affected organs.

Question 16

After a visit with her niece who had an active upper respiratory infection, Emma was worried that she would become ill as well. After a week, she still had no symptoms. What might explain Emma's response to exposure to this respiratory virus?

Accepted Answer

The answer of After a visit with her niece who...

Question 17

A primary immune response results in production of __________ and IgG. A secondary immune response results in production of __________.

Accepted Answer

In a primary immune response, the body first produces IgM antibodies followed by IgG antibodies for a more specific response. In a secondary immune response, the body primarily produces IgG antibodies, which are more specific and produced more quickly than in the primary response.

Question 18

In an autoimmune disease, what is targeted by the autoantibodies?

Accepted Answer

Autoantibodies in autoimmune diseases target the body's own tissues and organs, mistakenly identifying them as foreign and harmful.

Question 19

Immediate-reaction hypersensitivity occurs when an allergen binds to cell-bound IgE. What is the result of this allergen-antibody interaction?

Accepted Answer

The binding of an allergen to cell-bound IgE primarily triggers mast cells to release histamine, which is a key mediator in allergic reactions, leading to symptoms such as itching, swelling, and redness.

Question 20

During an immune response, what cell types are able to directly bind or interact with an intact antigen?

Accepted Answer

B cells and macrophages can directly bind or interact with intact antigens. B cells do so through their B cell receptors (BCRs), which can recognize specific antigen structures. Macrophages can bind antigens as part of their role in phagocytosis and antigen presentation.

Quiz 14: Lymphatic System and Immunity