C6.1: HOST DEFENSE MECHANISMS

Question 1

Ways in which the body protects itself from
pathogens

Answer 1

Host Defense Mechanisms

Question 2

How does host defense mechanism happen?

Answer 2

If the enemy (pathogens) breaks through the
first line of defense, it will encounter and, it is
hoped, be stopped by the second line of defense.If the pathogens manages to break through and
escape the first two lines of defenses, there is a
third line of defense is ready to attack it.

Question 2

What are the host mechanisms for the 1st line of defense

Answer 2

-Skin
-Mucous membranes
-Secretion of skin and mucous membrane

Question 3

What are the host mechanisms for the 2nd line of defense

Answer 3

-Phagocytic leukocytes
-Antimicrobial proteins
-Inflammatory response
- fever

Question 3

What are the host mechanisms for 3rd line of defense

Answer 3

-Lymphocytes
-Antibodies
-Memory cells

Question 4

The sticky mucous that is produced by
______ with the mucous membranes
serves to ____

Answer 4

goblet cells; entrap invaders.

Question 4

In the third line of defense, special proteins called
_____ are usually produced in the body in response
to the presence of foreign substances called _____.

Answer 4

antibodies; antigens

Question 5

The _____, ________ and ____
of the skin inhibit the growth of pathogens

Answer 5

dryness, acidity (approximately pH 5.0 ) and temperature (< 37 ͦC )

Question 6

serves as a nonspecific host defense mechanism
by flushing organisms from the pores and the surface of the
skin.

Answer 6

Perspiration

Question 7

Perspiration also contains the enzyme,
____–, which degrades
peptidoglycan in the bacterial cells (especially Gram positive
bacteria.)

Answer 7

lysozyme

Question 8

is a protein that binds iron, a
mineral that are required by all pathogens.

Answer 8

Lactoferrin

Question 9

is an enzyme that produces superoxide radicals,
highly reactive forms of oxygen, which are toxic to bacteria.

Answer 9

Lactoperoxidase

Question 10

present on the epithelial cells of the posterior nasal membranes, nasal sinuses, bronchi, and trachea sweep the trapped dust and microbes upward toward the throat where they are swallowed or expelled by sneezing/coughing

Answer 10

Cilia (mucociliary covering)

Question 11

____in the mucous membranes may also be
involved in this mucociliary clearance mechanism.

Answer 11

Phagocytes

Question 12

can be thought of as nonspecific host
defense mechanism, because thousands of bacteria are
removed from the oral cavity every time we swallow.

Answer 12

Swallowing of saliva

Question 13

factors that protects the digestive
system from bacterial colonization

Answer 13

Digestive Enzymes
Acidity of the stomach (approximately pH 1.5
Alkalinity of the intestines

Question 14

The ______, which is secreted by the liver into the small
intestine, lower the surface tension and causes chemical
changes in bacterial cell walls and membranes that make
bacteria easier to digest.

Answer 14

bile

Question 15

is an interaction where resident
microbes of the indigenous microflora prevent the
colonization of new arrivals to a particular anatomical site.

Answer 15

Microbial antagonism

Question 16

F actors that attributes to the inhibitory
capability of indigenous microflora

Answer 16

Competition for colonization sites
Competition for nutrients
Production of substances that kill other bacteria.

Question 17

The _______
is a group of cells, tissues
and organs that work
together to protect the
body. This is the ____

Answer 17

second line of defense; immune
system

Question 18

It is the Cornerstone of
Inflammation and Specific Immunity

Answer 18

Phagocytosis

Question 19

The General activities of Phagocytes

Answer 19

*To survey the tissue compartments and discover
microbes, particulate matter;
*To ingest and eliminate these materials; and
*To extract immunogenic information (antigen) from
foreign matter

Question 20

General purpose phagocytes

Answer 20

Neutrophils

Question 21

These cells primarily attack bacteria. They are dispensable,
rather like pawns on a chessboard.

Answer 21

Neutrophils

Question 22

They rush to the site of incoming bacteria to fight them, but
are easily killed.

Answer 22

Neutrophils

Question 23

These cells are like the bosses.

Answer 23

T helper cells

Question 24

They give instructions to other cells by
producing signals.

Answer 24

T helper cells

Question 25

These are killer cells.

Answer 25

Cytotoxic (killer) T cells

Question 26

They punch holes in the walls of the
pathogen cell so that the contents ooze out.

Answer 26

Cytotoxic (killer) T cells

Question 27

means ‘big eater’.

Answer 27

Macrophage

Question 28

These cells ‘eat’ (ingest) or clean up the mess of
dead cells.

Answer 28

Macrophage

Question 29

These cells are like the spies.

Answer 29

Dendritric cells

Question 30

They notice if there is an invader and then
present evidence of the invader to T cells in
the lymph nodes.

Answer 30

Dendritric cells

Question 31

These produce antibodies, which lock onto the antigen of
invading bacteria and immobilise them until the
macrophage consumes them.

Answer 31

B cells

Question 32

Some B cells become memory cells after being activated by
the presence of _______.

Answer 32

antigen

Question 33

These cells are able to live for a long time and can respond
quickly following a second exposure to the same antigen.

Answer 33

B cells

Question 34

When the infection is gone, the immune system
needs to be calmed down (or the killer cells may
keep killing).

Answer 34

Suppressor T cells

Question 35

The ____slow down or turn off the
immune system to prevent damage to good cells.

Answer 35

Suppressor T cells

Question 36

The lymphatic system is a
system of thin tubes that runs
throughout the body. These
tubes are called _____ . They contain ___.

Answer 36

lymph vessels; lymph

Question 37

is fluid in which
white blood (immune) cells
are found.

Answer 37

Lymph

Question 38

are small, round masses of tissue that are found
in certain areas (such as the neck, groin and armpits). They filter

Answer 38

Lymph nodes

Question 39

They filter
bacteria and other foreign materials out of lymph and expose
them to B and T cells and macrophages that can engulf them.

Answer 39

Lymph nodes

Question 40

It functions to store and delivered iron to the host cells.

Answer 40

Transferrin

Question 41

A temperature greater than 37.5 ͦ C ( 100100ͦ F) is generally considered
.

Answer 41

fever

Question 42

A glycoprotein synthesized in the liver, has a high affinity for iron

Answer 42

Transferrin

Question 43

Fever can be ____ or ____

Answer 43

exogenous; endogenous

Question 43

Substances that stimulate the production of fever is
called _________ which
may originated either outside or inside the body.

Answer 43

pyrogens or pyrogenic substance

Question 43

Those form the outside of the body includes
pathogens and various pyrogenic substance that
produces or release _____

Answer 43

endotoxins

Question 43

is an example of pyrogen
that is produced within the body (endogenous pryrogen)

Answer 43

Interleukin I (IL-1 )

Question 43

Small, antiviral proteins produced by virus infected cells.

Answer 43

Interferons

Question 43

What are the Three known types of interferon,

Answer 43

alpha ( α ), beta β ), and γ )

Question 43

(α) interferon is produced by ________

Answer 43

B lymphocytes (B cells), macrophages,
and monocytes

Question 43

(β) interferon is produced by

Answer 43

fibroblast and other virus infected cells

Question 43

(γ) interferon is produced by

Answer 43

activated T lymphocytes (T cells) and natural
killer cells (NK cells)

Question 43

localized physical condition in which part of the body becomes
reddened, swollen, hot, and often painful, especially as a
reaction to injury or infection

Answer 43

Inflammation

Question 43

______begin when phagocytes move to
the site where they are needed. This directed migration is called _____ results of chemical attractants called ______

Answer 43

Phagocytosis; chemotaxis; chemotactic agent.