20.E: Innate Nonspecific Host Defenses (Exercises)
20.1: Physical Defenses
Nonspecific innate immunity provides a first line of defense against infection by nonspecifically blocking entry of microbes and targeting them for destruction or removal from the body. The physical defenses of innate immunity include physical barriers, mechanical actions that remove microbes and debris, and the microbiome, which competes with and inhibits the growth of pathogens. The skin, mucous membranes, and endothelia throughout the body serve as physical barriers.
Multiple Choice
Which of the following best describes the innate nonspecific immune system?
- a targeted and highly specific response to a single pathogen or molecule
- a generalized and nonspecific set of defenses against a class or group of pathogens
- a set of barrier mechanisms that adapts to specific pathogens after repeated exposure
- the production of antibody molecules against pathogens
- Answer
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B
Which of the following constantly sheds dead cells along with any microbes that may be attached to those cells?
- epidermis
- dermis
- hypodermis
- mucous membrane
- Answer
-
A
Which of the following uses a particularly dense suite of tight junctions to prevent microbes from entering the underlying tissue?
- the mucociliary escalator
- the epidermis
- the blood-brain barrier
- the urethra
- Answer
-
C
Fill in the Blank
The muscular contraction of the intestines that results in movement of material through the digestive tract is called ________.
- Answer
-
peristalsis
______ are the hair-like appendages of cells lining parts of the respiratory tract that sweep debris away from the lungs.
- Answer
-
cilia
Secretions that bathe and moisten the interior of the intestines are produced by _______ cells.
- Answer
-
goblet
Short Answer
Differentiate a physical barrier from a mechanical removal mechanism and give an example of each.
Identify some ways that pathogens can breach the physical barriers of the innate immune system.
20.2: Chemical Defenses
Numerous chemical mediators produced endogenously and exogenously exhibit nonspecific antimicrobial functions. Many chemical mediators are found in body fluids such as sebum, saliva, mucus, gastric and intestinal fluids, urine, tears, cerumen, and vaginal secretions. Antimicrobial peptides (AMPs) found on the skin and in other areas of the body are largely produced in response to the presence of pathogens. These include dermcidin, cathelicidin, defensins, histatins, and bacteriocins.
Multiple Choice
Which of the following serve as chemical signals between cells and stimulate a wide range of nonspecific defenses?
- cytokines
- antimicrobial peptides
- complement proteins
- antibodies
- Answer
-
A
Bacteriocins and defensins are types of which of the following?
- leukotrienes
- cytokines
- inflammation-eliciting mediators
- antimicrobial peptides
- Answer
-
D
Which of the following chemical mediators is secreted onto the surface of the skin?
- cerumen
- sebum
- gastric acid
- prostaglandin
- Answer
-
B
Identify the complement activation pathway that is triggered by the binding of an acute-phase protein to a pathogen.
- classical
- alternate
- lectin
- cathelicidin
- Answer
-
C
Histamine, leukotrienes, prostaglandins, and bradykinin are examples of which of the following?
- chemical mediators primarily found in the digestive system
- chemical mediators that promote inflammation
- antimicrobial peptides found on the skin
- complement proteins that form MACs
- Answer
-
B
Fill in the Blank
________ are antimicrobial peptides produced by members of the normal microbiota.
- Answer
-
bacteriocins
________ is the fluid portion of a blood sample that has been drawn in the presence of an anticoagulant compound.
- Answer
-
plasma
The process by which cells are drawn or attracted to an area by a microbe invader is known as ________.
- Answer
-
chemotaxis
Short Answer
Differentiate the main activation methods of the classic, alternative, and lectin complement cascades.
What are the four protective outcomes of complement activation?