Topic 17

Question 1

What is the entire collection of various defenses a host has against infection called?

Answer 1

Immune system

Question 2

What is immunity (resistance)?

Answer 2

The ability of the body to protect itself from diseases caused by microorganisms and their products

Question 3

What is a lack of immunity called?

Answer 3

Susceptibility

Question 4

What are the two types of immunity?

Answer 4

1) Innate; 2) Acquired (adaptive)

Question 5

Describe innate immunity

Answer 5

Born with these defense mechanisms; general defenses; no memory of past exposure; every response is the same; provides immediate and maximal response

Question 6

Describe acquired (adaptive) immunity

Answer 6

Immune system learns how to kill specific pathogens when exposed; uses a specific defense; remembers this information for later exposures; response is faster each time the body is exposed; it has a delayed response (lag between exposure and maximal response)

Question 7

What are the types of first line innate response?

Answer 7

1) Anatomical/physical barriers; 2) Normal flora function

Question 8

What are the four types of anatomical/physical barriers employed?

Answer 8

1) Skin; 2) mucus membranes; 3) tears, saliva, and sweat glands 4) stomach secretions

Question 9

Describe how the skin barrier helps protect us from microbes

Answer 9

1) It’s made of tightly packed epithelial cells; 2) top layer is made of waterproof keratin; 3) top layer continuously sheds; 4) it’s dry, which helps inhibit microbial growth; 5) there are sebaceous glands on the skin which produce pH lowering oil, and secrete antimicrobial fatty acids

Question 10

Describe how the mucus barrier helps protect us from microbes

Answer 10

1) It lines the gastrointestinal, respiratory, and genitourinary tracts; 2) outer epithelial cells secrete mucus to trap microbes; 3) mucus is removed from the body by cilia

Question 11

Describe how the tears, saliva, and sweat barrier helps protect us from microbes

Answer 11

1) Tears and saliva have lysozomes (enzymes) that degrade the peptidoglycan in the cell wall of bacteria; 2) saliva also contains urea and uric acid to keep the pH acidic; 3) sweat glands have high lactic acid content, electrolytes that inhibit microbial growth, and secrete antimicrobial peptides

Question 12

Describe how the stomach secretions barrier helps protect us from microbes

Answer 12

1) Stomach acid contains hydrochloric acid, enzymes, mucus, and a pH level of approximately 1.2 - 3 which destroys most pathogens and toxins

Question 13

Describe how the normal flora function helps protect us from microbes

Answer 13

1) Takes up space inhibiting growth of new/foreign bacteria; 2) maintains or alters pH levels, nutrient availability, oxygen levels

Question 14

What physiological (chemical) actions make up the second line of defense?

Answer 14

1) Phagocytosis; 2) interferons; 3) inflammation; 4) initiated by immune cells that circulate in your blood

Question 15

How does the body differentiate foreign cells from our own cells?

Answer 15

Protein receptors within the membrane of macrophages detect foreign molecules and signal production of chemicals that stimulate an inflammatory response (nonspecific) and promote the activity of B and T cells (specific), both of which kill the invading pathogen

Question 16

What is our blood made of?

Answer 16

1) Plasma (liquid) and formed elements (cells and cell fragments); 2) erythrocytes (RBCs) and platelets; 3) leukocytes (WBCs), also known as phagocytes; 4) lymphocytes (which kill infected cells and tumor cells); 5) monocytes (which recycle worn out RBCs and dead tissue)

Question 17

What is phagocytosis?

Answer 17

Leukocytes (WBCs) eat and digest foreign matter; engulment of microbes by phagocytic cells; an inflammatory response

Question 18

List three types of phagocytic cells

Answer 18

1) Neutrophils; 2) eosinophils; 3) macrophages

Question 19

What are the four stages of phagocytosis?

Answer 19

1) Chemotaxis; 2) adherence; 3) ingestion; 4) killing/elimination

Question 20

Describe the chemotaxis stage

Answer 20

Chemical signals attract phagocyte

Question 21

Describe the adherence stage

Answer 21

Phagocyte plasma membrane interacts with the microbe; microbial capsules interfere with adherence

Question 22

Describe the ingestion stage

Answer 22

Microorganism brought into the phagocyte in a membrane bound vesicle called phagosome

Question 23

Describe the killing/elimination stage

Answer 23

The phagosome fuses with lysosome and the microbe is killed, digested, and removed from the cell (exocytosis)

Question 24

What are interferons?

Answer 24

Small proteins produced by certain WBCs and tissue cells with anti-viral activity; they are produced in response to viral infection; they bind to the cell surface and induce expression of anti-viral proteins by healthy cells

Question 25

What are the symptoms of inflammation?

Answer 25

1) Redness; 2) warmth; 3) swelling (edema); 4) pain

Question 26

What is a fever?

Answer 26

1) It’s a systemic inflammatory response initiated by circulating pyrogens which increase temperature all over the body; when phagocytes recognize pyrogens, they secrete cytokines, which in turn affects the body’s internal thermostat located in the hypothalamus of the brain

Question 27

What are the benefits of fever?

Answer 27

1) It inhibits multiplication of temperature-sensitive microorganisms; 2) impedes nutrition of bacteria by reducing the available iron; 3) increases metabolism and stimulates immune reactions and protective physiological processes

Question 28

When does specific immunity, the third line of defense, begin?

Answer 28

When foreign particles (proteins, glycoproteins), which are unlike the host proteins, enter the body

Question 29

What are these foreign particles called?

Answer 29

Non-self antigens because they stimulate production of antibodies

Question 30

What is an antigen?

Answer 30

Any substance that causes your immune system to produce antibodies (including casules, cell walls, flagella, fimbriae, toxins of bacteria, coats of viruses, proteins on surface of foreign blood or cancer cells, which contain specific markers on the outside - protein or polyscaccraride)

Question 31

What are antibodies?

Answer 31

Blood proteins produced in response to and which counteract specifc foreign antigens; they aid in the removal of antigens and prevent the ability of pathogens to cause widespread infection; they are large Y-shaped glycoprotein that belong to the immunoglobulin family (Ig)

Question 32

Which cells produce antibodies?

Answer 32

Lymphocyte cells

Question 33

What are two types of antibodies?

Answer 33

B-cells and T-cells

Question 34

Where are B-cells and T-cells produced?

Answer 34

Bone marrow

Question 35

List differences between B-cells and T-cells

Answer 35

B-Cells mature in the bone marrow, are important for antibody production, build an army of antibodies and let them do the fighting; T-cells mature in the thymus, play a role in cell-mediated immunity, and directly fight bacteria

Question 36

What are the characteristics of B-cells?

Answer 36

1) They act in the humoral (antibody) immunity; they bind to antigens to form an antigen-fragment complex which is recognized by activated helper T-cells

Question 37

What are three types of T-cells?

Answer 37

1) Helper T-cells; 2) cytotoxic T-cells; 3) suppressor T-cells

Question 38

What are the characteristics of helper T-cells?

Answer 38

They stimulate B-cells and T-cells (B-cells must be activated by helper T-cells before they can produce antibodies) (AIDS causes a loss of helper T-cells causing a lack of antibody production

Question 39

What are the characteristics of cytotoxic T-cells?

Answer 39

Responsible for cell mediated immunity; directly attack foreign cells physically and chemically

Question 40

What are the characteristics of suppresor T-cells?

Answer 40

Inhibit B and T-cell activity; modulate (turn off) the immune response

Question 41

What are the main classes of antibodies and their characteristics?

Answer 41

1) IgG (gamma globulin): 80% of all antibodides, transmitted from mother to child in uterus, protect against bacteria/viruses and aid macrophages; 2) IgD (blood, lymph, B-cells): presence on B-cells indicates immune response; 3) IgE (minority): important in allergic reactions and release of histamine; 4) IgA (mucus membranes/secretions): help prevent attachment to mucosal surfaces; 5) IgM (macro size): clumping of viruses and bacteria, first to react during an infection (good for diagnostic tool)

Question 42

List antibody functions

Answer 42

1) Bacterial cell “tagged” with antibodies; 2) opsonization; 3) neutralization; 4) agglutination; 5) complement fixation

Question 43

What are monoclonal antibodies?

Answer 43

Production of antibodies using biotechnology; highly specific to the protein of interest; only binds to a single site; expensive, but highly renewable

Question 44

What is a vaccine?

Answer 44

An injection of a tiny amount of weakened non-infectious virus or bacteria, causing the body’s immune system to generate antibodies

Question 45

Who created the first vaccine and what was it created for?

Answer 45

Edward Jenner, small pox

Question 46

What is an allergy?

Answer 46

The body’s reaction to an everyday item that it incorrectly detects as a threat, and launches an immune response