12.8.1 The Immune Response: Nonspecific Defenses

Question 1

The Immune Response: Nonspecific Defenses

Answer 1

• The immune system functions as the body’s defense against pathogens and abnormal cells of the body.
• The immune response consists of non-specific and specific defenses. Non-specific defenses are those that do not target a particular pathogen, while the specific defenses recognize and defend against specific pathogens.
• The first line of non-specific defenses protects against exterior invasions, and consists of the skin, mucous membranes, and bodily secretions.

Question 2

first line of defense

Answer 2

• The body’s first line of defense protects against the invasions of pathogens. The box to the left outlines the three major components of the first line of defenses.
• They include:
  · skin
  · mucous membranes
  · secretions
• These components are referred to as nonspecific because they do not distinguish one pathogen from another.

Question 3

second line of defense

Answer 3

• The body’s second line of defense is also nonspecific and defends the body against pathogens that have evaded the first line of defenses.
• These include:
  · phagocytes
  · antimicrobial proteins
  · inflammation

Question 4

inflammatory response

Answer 4

• The inflammatory response is a localized nonspecific
  response to an invading pathogen or physical injury, like a splinter. The diagram to the left illustrates the general events of an inflammatory response to a splinter.
• First the injured tissue releases chemicals such as histamines and prostaglandins. Histamine is a chemical that causes nearby capillaries to dilate and become “leaky”. Both of these effects result in an increased blood flow to the site of injury. The increased blood flow can often be observed in the red-colored skin surrounding the injured tissue.
  Prostaglandins also promote blood flow to the area.
• Chemicals released from the injury site attract phagocytic white blood cells. These cells migrate from the bloodstream and ingest invading organisms and debris, allowing the tissue to heal.

Question 5

Employing about 20 proteins, ________________ consists of a series of reactions that lead to the death of invading microbes.

Answer 5

• the complement system

Question 6

Which of the following does not serve as a part of the body’s nonspecific defense system?

Answer 6

• Antibodies

Question 7

What is the role of basophil and mast cells during an immune response?

Answer 7

• They release histamine, which increases membrane permeability.

Question 8

Which of the following is responsible for triggering allergy symptoms?

Answer 8

• Mast cells

Question 9

Which of the following are not involved in the first line of defense of the immune system?

Answer 9

• white blood cells

Question 10

Which of the following is likely to occur during the early stages of inflammation?

Answer 10

• release of histamine from basophils

Question 11

Some believe that taking aspirin to lower a fever is not advisable. Why would this be?

Answer 11

• Raising body temperature is thought to reduce bacterial growth rate.

Question 12

Germs can penetrate the eyes, but bacterial infections in the eye are relatively rare. Why is this?

Answer 12

• Tears, which constantly wash over the eye, contain an anti-bacterial enzyme.