Immune System

Question 1

First line of Defense

Answer 1

Non-specific way of preventing invaders from entering the body

Question 2

Skin

Answer 2

Physical barrier

pH 3-5 due to oily secretions

Question 3

Antimicrobial Proteins

Answer 3

i.e. Lysozymes that break down cell walls in bacteria

Fond in saliva, sweat, tears

Question 4

Cilia

Answer 4

Found in lungs

Sweep out harmful bacteria

Question 5

Gastric Juice

Answer 5

Kills many microbes in stomach

Question 6

Symbiotic Bacteria

Answer 6

In digestive tract and vagina

Outcompete other bacteria that could be harmful

Question 7

Second Line of Defence

Answer 7

Non-specific way of defence

Phagocytes
Complement
Interferons
Inflammatory Response

Question 8

Phagocytes

Answer 8

Cells that engulf harmful particles via phagocytosis

Question 9

Leukocyte

Answer 9

WBC

Neutrophils
Monocytes (become macrphages)

Type of phagocyte

Question 10

Natural Killer Cells

Answer 10

NKs

Type of phagocyte

Attack tumors or pathogen infected cells

Question 11

Complement

Answer 11

Proteins that “complement” other defenses

Attract phagocytes where they are needed

Also promote cell lysis if the cell is a threat

Question 12

Interferons

Answer 12

Cells that are infected by a virus secrete interferons to promote neighbouring cells to produce virus fighting proteins

Question 13

Inflammatory Response

Answer 13

Series of non-specific events that occurs in response to a pathogen

Histamine—> Vasodilation—> Phagocytes—> Complements

Question 14

Inflammatory Response-Histamine

Answer 14

Released by basophils (WBC)

Increases permeability of the capillaries to WBC to allow them to engage pathogens in infected tissues

Question 15

Inflammatory Response-Vasodilation

Answer 15

Occurs in response to histamine

Results in increased blood supply to affected area, allows WTV to more easily access where they are needed

Causes redness, swelling, increased temperature during a fever

Question 16

Inflammatory Response- Phagocytes

Answer 16

Attracted to the injured area to engulf pathogens

Question 17

Inflammatory Response- Complements

Answer 17

Leave chemical gradients, allowing phagocytes to follow them to the infected area

Help phagocytes engulf pathogens

Stimulate basophils to release histamine

Assist in lysis of foreign cells when necessary

Question 18

Third Line of Defense

Answer 18

Immune response- specific

Question 19

Antigen

Answer 19

Molecules detected as foreign by the immune response

Question 20

Lymphocytes

Answer 20

Major component of immune response

WBCs originating in bone marrow, spend most of their time in lymph nodes, thymus gland, and spleen

Question 21

Lymphocytes- B Cells

Answer 21

Originate and mature in bone marrow

PM of B cells contain Ab

Once Ab on B cell binds its specific antigen, B cell proliferates into 2 types of daughter cells (Plasma and Memory)

Question 22

Ab

Answer 22

Specific to a certain antigen

Constant region- same for Ab in the same class and species (recognized by receptors on some cells)

Variable region- responsible for recognizing antigen

Question 23

Ab Bind Antigen

Answer 23

Inactivates antigen until it is phagocytosed by macrophage

Question 24

Ab bind surface antigen of cell

Answer 24

Stimulates Complement protein to come and lyse cell

Question 25

B-Cells (Plasma Cells)

Answer 25

Release Ab into bloodstream, allowing them to circulate throughout the body and bind to antigen

Question 26

B-Cells (Memory Cells)

Answer 26

Keep their Ab bound to their membranes

Long lived after coming int contact with an antigen

Reason one can be immune to many diseases after a previous exposure

Question 27

Lymphocytes- T Cells (Recognition)

Answer 27

Originate in bone marrow, but mature in thymus gland

Have antigen receptors on surface, but are not Ab

Receptors recognize foreign cells via MHC Marks (self vs. non-self)

T cells look for displays of mixture of self/non-self markers on a self (indicates cell infected by virus)

Cancerous/transplanted cells are recognized as foreign

Question 28

T-Cell Division

Answer 28

T cell divides and produces 2 types of daughter cells

Cytotoxic/Killer T Cells- recognize and puncture foreign cells (lysis)

Helper T cells - stimulate proliferation of cytotoxic T cells and B cells

Question 29

Clonal Selection

Answer 29

Antigen binds to B cell, or foreign cell binds to T cell, causing proliferation into identical daughter cells

Clonal selection= cell bound to antigen was “selected” for, and cells that are not bound will not divide

Question 30

Cell Mediated Response

Answer 30

Uses T cells to respond to foreign cells or cells invaded by pathogens

T cells—> cytotoxic T cells (destroy foreign cells)

T cells—> helper t cells (bind to macrophages that have already engulfed pathogens, marking them for destruction)—> Interleukins (stimulate proliferation of T/b cells)

Question 31

Humoral Response

Answer 31

Uses Ab to respond to antigens on pathogens in the blood or lymph

Process of B cell–> plasma cells (release Ab to bind antigens)

B cells—> memory cells (future immunity)

Also involves macrophages and helper T cells stimulating production of more b cells

Sometimes, antigen binding to b cell does not directly stimulate the production of additional b cells

Pathogen needs to be engulfed by macrophage first, then helper t cell can bind macrophage, release interleukin and stimulate b cell production

Question 32

Passive Immunity

Answer 32

Passing Ab from a previously infected individual to someone else who is newly infected with the disease

Newborn infants protected (Ab pass from both placenta and breast milk)