Chapter 12 and 13: Host Defenses

Question 1

review from last chapter: what is the difference
between sterilization and disinfection?

Answer 1

-sterilization is the complete removal/destruction of all viable microorganisms
-disinfection is the killing or reducing the amount of microorganisms on inanimate objects

Question 2

what is immunology?

Answer 2

the study of host defenses, defending against foreign objects
-thinking about what= our body’s cells vs not

Question 3

what are some types/categories of defense mechanisms?
(we’ll get into depth of each later)

Answer 3

-physical
-chemical
-biological

Question 4

what are the 2 types of immunity found in the immune system?
be able to describe each type

Answer 4

-Innate (natural) immunity: nonspecific defenses that attack foreign material
-acquired (adaptive) immunity: specific defenses that develop to specific foreign material (note that the response is quicker and stronger with each encounter of the same antigen)

Question 5

how many lines of defenses does the immune system have?

Answer 5

3

Question 6

what is the immune system responsible for?

Answer 6

-surveillance of the body
-recognition of foreign material (knowing what’s self and not)
-destruction of entities deemed to be foreign

Question 7

how are immune cells are able to distinguish what cells are not self cells?

Answer 7

cellular markers!
pathogen associated molecular patterns (PAMPS) or microbe associated molecular patterns (MAMPs)

Question 8

why are Pattern Recognition Receptors (PRPs) important for host cells?

Answer 8

they help determine if an immune response is necessary (and if so how strong the response needs to be) as they bind to the non self cells

Question 9

what is autoimmunity?

Answer 9

when the body can not distinguish between self cells and non-self cells
ex: Lupus and Rheumatiod arthritis

Question 10

why are leukocytes important in the immune system?

Answer 10

they help detect pathogens via MAMPs/PAMPs

Question 11

name the different granulocyte WBCs and their functions

Answer 11

-mast cells: triggers local inflammatory and allergic responses
-neutrophils: phagocytic
-basophils: inflammatory and allergy responses
-eosinophils: inflammatory (note: important in parasitic infections)

Question 12

name the different agranulocyte WBCs and their functions

Answer 12

-macrophages: type of monocyte that is important for phagocytosis
-dendritic cells: type of monocyte that is used to help process foreign matter (note: “bridge innate/acquired immunity)
-b lymphocytes (B cells): produces antibodies
-t lymphocytes (T cells): can kill cells or help other immune cells

Question 13

what is the function of platelets?

Answer 13

blood clotting and inflammation
-also plays a role in destruction of blood-borne pathogens

Question 14

what is the function of red blood cells?

Answer 14

to transport oxygen and carbon dioxide for proper cellular functions

Question 15

be able to describe the primary lymphatic organs/tissues and what they are used for:

Answer 15

-thymus: site where immature lymphocytes mature to T cells
-bone marrow: site of blood cell production and maturation of B cells

Question 16

be able to describe the secondary lymphatic organs/tissues and what they are used for:

Answer 16

know that this is where lymphocytes become activated
-spleen: helps filter blood (and RBCs from circulation), removes blood-borne particles
-lymphatics: network system that transports lymph
-peyer’s path: provides protection in the intestines and the appendix

Question 17

what is lymph?

Answer 17

fluid carried by lymphatic circulation
(note: contains WBCs and lymphocytes)

Question 18

understand what makes up the lymphatic system

Answer 18

-tonsils: 3 types (palantine, pharyngeal and lingual) and are the first detectors of infection in the oral cavity
-lymph nodes: site of lymph filtration
-lymph vessels (arteries, veins and capillaries): transports lymph toward the circulation
-lymph tissue: think Skin Associated Lymphatic Tissue, MALT (mucosal), GALT (gut), BALT (bronchial)

Question 19

what is the immune system’s first line of defense (physical mediators) impacted by?

Answer 19

-direct factors (nutrition, physiology, age, genetics)
-indirect factors (personal hygiene, socioeconomic status, living conditions)

Question 20

be able to describe what is included within the first line of defense for the immune system:

Answer 20

-skin: effective mechanical barrier (covers entire body)
-mucous membrane: skin modification near internal structures (used to trap invaders and produces enzymes that are anti-microbial
-respiratory system: breathing mechanisms that express foreign invaders (ex: coughing and sneezing)
-gastrointestinal tract: stomach (note acidity) and intestinal microbiota prevent growth of pathogens and adhesion to lining
-genitourinary tract: filter in the kidneys to physically remove pathogen

Question 21

what are some examples of flushing (host’s secretions)?

Answer 21

eyes watering, (tears), saliva, sweating, coughing, sneezing etc

Question 22

be able to describe what is included in the second line of defense for the immune system:

Answer 22

-lysozymes: enzymes found in secretion that break down the PG of the cell membrane
-cytokines: proteins released by cells in response to certain stimuli
-histamines: vasodilators/vasoconstrictors that change the diameter of blood vessels
-interleukins: have roles in inflammation and regulation of immune responses
-interferon: proteins produced by WBCs and tissue cells that defend against microbes (specifically viruses)
-defensin: small peptide with antimicrobial activity that can be inserted into bacterial membranes
phagocytosis: basic understanding of cell ingestion of non self cells

Question 23

what is the complement cascade?

Answer 23

a group of 20-30 plasma proteins that act to “complement” or help other host defenses
-usually activation of 1 component triggers the next

Question 24

what are 3 ways to activate Complement Cascade?

Answer 24

-Classical pathway (Antigen and antibody complex triggers C3 cleavage)
-Lectin pathway (protein bound to specific CHO)
-Alternative pathway (triggered by material with repetitive structures)

Question 25

what is phagocytosis?

Answer 25

form of endocytosis where a cell ingests large particles into membrane-bound vesicles (called phagosomes)

Question 26

understand the process of phagocytosis:

Answer 26

1. Chemotaxis and Adhesion: cells=drawn to foreign material and extends receptors (PAMPs) to attach together
2. Engulfment and Phagosome Formation: foreign material is enclosed into a vacuole inside the cell called the phagosome
3. Phagolysosome Formation, Killing and Destruction: lysosomes break down PG of foreign material in phagosome to form a phagolysosome and granules are released into the vacuole to digest the material

Question 27

what is inflammation?

Answer 27

natural nonspecific protective response to injury/destruction/infection that blocks the spread of infectious agents and help to reduce further host damage

Question 28

what are the 4 goals of inflammation?

Answer 28

-to mobilize immune responses to the site of injury
-to mobilize repair mechanisms to heal injury
-clear away harmful substances, destroy microbes
-prevent further invasion

Question 29

TRUE or FALSE: inflammation can be acute but can not be chronic?

Answer 29

FALSE: it can be both acute (lasting days to weeks) or chronic (prolonged stimulation)

Question 30

what are signs of an inflammatory response?

Answer 30

-redness: vasodilation, increased circulation in injured tissues
-warmth: heat given off by increased blood flow
-pain: stimulation of nerve endings
-swelling: increased fluid escaping into tissues
-altered function: loss of function (extreme)

Question 31

what are the stages of inflammation?

Answer 31

-Chemotaxis and Diapedesis: chemical stimulus given off at site of injury or infection and then migration of WBCs and neutrophils to specific tissues (causing redness and warmth to area)

-Edema and Pus: the result of influx of fluid (contains plasma proteins and blood cells) into tissues helps trap microbes and prevent their spread.
NOTE: pus=combination of dead WBCs, dead tissue and dead microbes

-Resolution, Repair, Scar Formation: fibrin creates clots to prevent infection spread, will result in normal function and complete repair or formation of scar tissue

Question 32

what does it mean to be pyogenic?

Answer 32

pus-forming bacteria

Question 33

what microorganisms are pyogenic?

Answer 33

Streptococcus and Staphylococcus

Question 34

what is a fever and what does it mean?

Answer 34

abnormally elevated body temperature
-means that substances re-set body temp to a higher setting (basically your body is trying to fight infection)

Question 35

understand the difference between low grade and high grade fevers:

Answer 35

low grade: 100-101 degrees F
high grade: 104-106 degrees F

Question 36

understand the difference between endogenous and exogenous pyrogens:

Answer 36

-endogenous pyrogens originate from inside the body, are released by cells during phagocytosis
-exogenous pyrogens come from outside the body

Question 37

what are some examples of endogenous pyrogens?

Answer 37

interleukin-1 (IL-1) and tumor necrosis factor (TNF)

Question 38

what are some examples of exogenous pyrogens?

Answer 38

viruses, bacteria, fungie, endotoxins, vaccines

Question 39

what are some benefits of having a fever?

Answer 39

-inhibits multiplication of temperature-sensitive microorganisms
-interferes with nutrition of bacteria by reducing the availability of iron
-increases metabolism and stimulates immune reactions (speeds up hematopoiesis, phagocytosis, and specific immune reactions

Question 40

understand what the 3rd line of defense of the immune system is and how it’s different from the first two lines of defense

Answer 40

Adaptive immunity: response is focused on a single antigen
-different from the first two lines of defense as Adaptive immunity is specific where the other lines are more broad in attack

Question 41

what two components does Adaptive immuntiy rely on?

Answer 41

recognition/specificity and memory

Question 42

what are the functions of adaptive immunity?

Answer 42

-recognize non-self cells
-remember non-self cells
-respond to non-self cells

Question 43

describe the characteristics of adaptive immunity:

Answer 43

-discrimination: between self and non-self, response=selective and tailored to pathogen

-diversity: ability to act specifically against a large variety of pathogens using a wide number of molecules

-specificity: defense directed specifically to a particular pathogen

-memory: upon subsequent encounter(s) response=stronger and quicker

-clonality: ability to generate millions of cells with the same specificity

Question 44

what is an antigen?

Answer 44

molecules that can be seen and identified by the immune system

Question 45

what is a immunogen?

Answer 45

molecules that provoke a response from the immune system

Question 46

what are some ways to acquire immunity?

Answer 46

naturally: acquired through normal life experiences

artificially: acquired purposefully through artificial/medical means

Question 47

understand the 4 types of specific immunity:

Answer 47

-Naturally Acquired Active immunity: a host develops after exposure to foreign substances
-Naturally Acquired Passive immunity: transfer of antibodies from one host to another (ex: mother to infant in breast milk)

-Artificially Acquired Active immunity: think a vaccine
-Artificially Acquired Passive immunity: pre-formed antibodies or lymphocytes produced by one host are introduced to another host

Question 48

what is the major histocompatibility complex (MHC)?

Answer 48

a set of genes that codes for human cell markers or receptors

Question 49

what is agranulocyte vs granulocyte?

Answer 49

agranulocyte: cells that do not have granules

granulocyte: cells that have granules