Question 1

During a major infection a fever often develops.What best explains the origin of this change in body temperature?

Accepted Answer

The immune system stimulates the brain to elevate the temperature, as an action that both limits bacterial growth and increases the rate of phagocytosis. This is known as the acute-phase response and is part of the body's immune defense against infections. The elevated body temperature helps to kill the bacteria and viruses that cause the infection, and it also stimulates the immune system to work more efficiently.

Question 2

Mammals use several strategies to prevent inhaled pathogens from entering the body through the lungs;in this instance the

Accepted Answer

Mucus secreted into the bronchioles traps pathogens and is eventually removed by the action of the cilia lining the airway. This is known as the mucociliary escalator and is one of the main defenses the body uses to prevent inhaled pathogens from entering the lungs.

Question 3

Which of the following immune cells is likely to be the first to encounter the pathogen during a bacterial infection?

Accepted Answer

Neutrophils are the most abundant type of white blood cell and are the first to be recruited to the site of infection. They are able to phagocytose (engulf and digest) bacteria and other pathogens. Macrophages also play a role in the innate immune response and may encounter the pathogen soon after neutrophils, but they may take longer to reach the site of infection. T helper cells and cytotoxic T cells are part of the adaptive immune response and are not involved in the immediate response to a bacterial infection.

Question 4

The blood of vertebrates contains a large number of cells that participate in both the innate and adaptive immune responses.To what group of blood components do these cells belong?

Accepted Answer

White blood cells, also known as leukocytes, are responsible for participating in both the innate and adaptive immune responses. Red blood cells carry oxygen, endothelial cells line the blood vessels, and blood platelets are involved in blood clotting.

Question 5

White blood cells (WBCs)have the unusual ability of being able to migrate through capillary walls into the surrounding tissues;why is this ability important?

Accepted Answer

In order for WBCs to effectively combat infections, they must be able to move from the circulatory system to the surrounding tissues where infections often occur. This is particularly important because the majority of infections start in locations outside of the circulatory system.

Question 6

A ________ can be a very challenging injury for the immune system to respond to because ________.

Accepted Answer

A puncture injury bypasses the first line of defense of the immune system, which is the skin, and can even bypass the second line of defense depending on the depth of the puncture. This makes it challenging for the immune system to respond effectively. The other options do not have the same level of difficulty for the immune system to respond to.

Question 7

The image below depicts

Accepted Answer

The image depicts the inflammatory response, as indicated by the blood vessels being porous and leaking fluid.

Question 8

Prostaglandins are lipid-based signaling molecules produced during an infection;they have a variety of effects that include

Accepted Answer

Prostaglandins are known to produce fever, pain, and drowsiness during an infection. They do not shut down capillaries near a wound, stimulate the production and release of histamines, or attach to pathogenic cells as secondary antigens to attract lymphocytes.

Question 9

The pathology of a virus is very different from that of a bacterium or fungal cell,and unique innate strategies exist for combating each.During a viral infection,infected cells may

Accepted Answer

The answer of The pathology of a virus is very...

Question 10

On occasion the immune response in inappropriate;for example,an allergy occurs when the immune system

Accepted Answer

An allergy occurs when the immune system initiates a response to a substance that is not actually pathogenic. This can range from mild reactions like hay fever to severe reactions like anaphylaxis.

Answer: B
 Autoimmune diseases occur when the immune system misinterprets normal body cells for pathogenic ones and mounts an immune response against those tissues. Examples include rheumatoid arthritis, lupus, and multiple sclerosis.

Answer: D
 Genetic defects can cause the immune system to either not respond enough or overreact. For example, people with primary immunodeficiency diseases have weakened immune systems, while those with autoimmune polyendocrine syndrome (APS) suffer from excessive immune responses that lead to multiple autoimmune diseases.

Question 11

Different genetic versions of a particular pathogen are known as different

Accepted Answer

Different genetic versions of a particular pathogen are called strains. Strains are variants of a species that differ from one another in some way, such as in their genetic makeup, virulence, or ability to cause disease. Antibodies are proteins produced by the immune system in response to infection, while disease hosts refer to organisms that harbor the pathogen and may transmit it to others.

Question 12

Histamine

Accepted Answer

Histamine makes the capillaries near a wound more porous, allowing white blood cells and other substances to enter the affected tissue and initiate the healing process.

Question 13

Complement proteins

Accepted Answer

Complement proteins can kill pathogenic cells directly by creating holes in their cell membranes or marking them for subsequent phagocytosis by cells of the immune system. They do not become antibodies and do not provide a protective covering on healthy cells. While they do attach directly to antigens on the surface of a pathogen, this is not their only function.

Question 14

Which of the following areas of the human body is NOT the location of a major concentration of white blood cells?

Accepted Answer

While the kidneys do have immune cells, they are not considered a major concentration of white blood cells like the other options listed. The tonsils, appendix, and spleen are all known locations for high concentrations of white blood cells to help protect the body from infection.

Question 15

The body responds to tissue damage by mounting an immediate and coordinated sequence of events called the ________ response.

Accepted Answer

The inflammatory response is the immediate and coordinated sequence of events that the body mounts in response to tissue damage. This response involves the release of histamine and prostaglandins which cause dilation and increased permeability of blood vessels, leading to swelling, redness, and heat in the affected area. This response helps to deliver immune cells and healing molecules to the site of injury, and also serves to contain and eliminate any pathogens that may have caused the damage. The specific immune response is a separate process that involves the targeting of specific pathogens by immune cells and antibodies.

Question 16

All of the following have been associated with disease,but ________ is a vector that introduces the actual pathogen rather than being a pathogen itself and does NOT cause any illness directly.

Accepted Answer

The flea is a vector that can transmit disease by introducing the actual pathogen (such as Yersinia pestis) into the host's bloodstream, but it does not cause illness directly. Bacteria, protists, and viruses can all be pathogens that cause disease.

Question 17

The site of an injury like a scratch or a splinter initially becomes red and painful.In some instances a yellowish thickened fluid may be present at the injury site.Commonly called pus,this fluid is

Accepted Answer

The yellowish fluid present at the injury site is pus, which is formed due to the accumulation of dead neutrophils, macrophages, and bacteria at the wound. These cells and bacteria are engulfed and destroyed by the immune system as a part of the inflammatory response, resulting in the formation of pus. The fluid also contains blood plasma and other proteins that leak out of the blood vessels due to inflammation.

Question 18

One of the most common examples of innate immunity component is the

Accepted Answer

The acidic environment in the stomach is an example of innate immunity component because it is a natural defense mechanism that helps to prevent harmful bacteria and viruses from entering the body through the digestive tract. It is not a product of adaptive immunity, like the production of antibodies from T and B cells or the development of memory cells following a vaccination.

Question 19

Macrophages may be unable to digest the pathogens they phagocytize.If so,the pathogen can still be prevented from affecting healthy tissues by

Accepted Answer

If macrophages cannot digest pathogens they phagocytize, they can still prevent the pathogen from affecting healthy tissues by encapsulating it within their cytoplasm. This prevents the pathogen from replicating and spreading to other cells in the body. Eventually, the macrophage may be able to digest the pathogen or it may release it for destruction by other immune cells. Options A, B, and C do not accurately describe how macrophages prevent the spread of pathogens they cannot digest.

Question 20

Which of the following would explain why organ donors and organ recipients are genetically matched before an organ transplant is performed?

Accepted Answer

The self-identification markers on the surface of cells are genetically determined. If the donor organ's cells do not have similar markers to the recipient's cells, the recipient's immune system is likely to recognize the organ as foreign and potentially attack it. Matching the genetic markers can reduce the risk of rejection.

Quiz 32: The Immune System