Chapter 8 - Immune System

Question 1

What is the spleen?

Answer 1

Location of blood storage and activation of B-cells

Question 2

What are lymph nodes?

Answer 2

Filter lymph and site where immune responses can be mounted

Question 3

Tell me the story of macrophages

Answer 3

When a pathogen breaks the first barrier of the immune system

1) macrophage engulfs the pathogen
2) digests the invader using enzymes

3) it presents pieces of the invader to other cells using Major histocompatibility complex
(MCH)

4) they release cytokines to stimulate inflammation

Question 4

What are some examples of macrophages in different parts of the body?

Answer 4

Microglia in the CNS

Langerhans cells in the skin

Osteoclasts in bone

Question 5

What are the two main classes of MHC?

Answer 5

MHC class 1:

• in all uncleared cells in the body
• the endogenous pathway
  
  • • it binds antigens from inside the cell
• cells can then be killed by T-cells

MHC class 2:

• exogenous antigens
• coming from outside the cell

Question 6

What are examples of MHC class II , professional antigen-presenting cells ?

Answer 6

• Macrophages,
• dendritic cells in the skin
• B-cells
• certain activated epithelial cells

Question 7

Natural killer cells

Answer 7

They can detect if MHC has been downregulated (by a virus)

**they induce apoptosis in these virally infected cells

**can also offer protection from growth of cancer

Natural killer cells: don’t mess, they will basically plant a bomb in you so you explode (apoptosis)

Question 8

What are three common types of Granulocytes

Answer 8

Basophils

Neutrophils

Eosinophils

Question 9

What is the most popular leukocyte in blood?

Answer 9

Neutrophils

Question 10

Tell me about neutrophils

Answer 10

Short lived

• phagocytic
• target bacteria
• they follow them using chemotaxis!!!
  
  • sensing different products from bacteria
• can detect bacteria once opsonized
  
  • marked w antibody from a B-cell

Fun fact: Pus is from dead neutrophils

Question 11

What are eosinophils ?

Answer 11

Involved in allergic reactions and invasive parasitic infections

Then they RELEASE HISTAMINE!

• causes vasodilation and leakiness in blood vessels
• allowing addditional immune cells to move out of bloodstream

Question 12

Basophils

Answer 12

Involved in allergic responses

*closely related to mast cells

**release lots of HISTAMINE…leading to inflammatory responses

Question 13

What is the adaptive immune system ?

Answer 13

Can identify specific invaders and mount an attack against that pathogen

Question 14

What are the two divisions of adaptive immune system?

Answer 14

HUMORAL IMMUNITY
- Bcells

CELL-MEDIATED (CYTOTOXIC) IMMUNITY
- T-cells

Question 15

What is humoral immunity?

Answer 15

Type of adaptive immunity

Involves production of antibodies from B-cells

Question 16

What are the three fates of antibodies secreted into body fluids?

Answer 16

1) once bound to specific antigen, antibodies attract other leukocytes to phagocytize them
OPSONIZATION

2) may cause pathogens to clump together
- AGGLUTINATE
- then they get phagocytized

3) they can block ability of a pathogen to invade tissues (by neutralizing it)

Question 17

What are the two types of daughter cells produced by by B-cells

Answer 17

Memory B cells:
- hang out in lymph nodes waiting for another invasion

Plasma Cells:

• produce large amount of antibodies
• **this is the basis for vaccination

Question 18

What is cytotoxic immunity (in a nutshell)?

Answer 18

Type of adaptive immunity based on cell0mediated immunity ..

ACTIVATION of T-CELLS

Question 19

What is positive and negative selection of T-cells?

Answer 19

Positive: maturing only cells that can respond to presentation of antigen on MHC

Negative: causing apoptosis in cells that are self-reactive

Question 20

What is OPSONIZATION?

Answer 20

Once bound to an antigen, antibodies can attract other leukocytes to phagocytize the antigens

Question 21

What is agglutination

Answer 21

Clumping up antibodies before they get phagotycised

Question 22

What are mast cells for?

Answer 22

They cause inflammatory response to pathogens

Question 23

What is the purpose of the constant region of antibodies

Answer 23

Binds to immune cells and tells them to get to work

Question 24

What is a naive B-cell?

Answer 24

Have not been exposed to antigen

- slow response

Question 25

What are the three major types of T-cells?

Answer 25

1) helper T-cells
2) Cytotoxic T-cells
3) suppressor t-cells

Question 26

What are helper T-cells?

Answer 26

Also called CD4+ T cells

• coordinate immune response by secreting lymphokines
• other immune cells are recruited

Question 27

What are cytotoxic T-cells ?

Answer 27

CD8+ cells

*capapble of directly killing virally infected cells by injectent toxic chemicals that promote apoptosis into the infected cell

CD8+ respond to MHC1 molecules so more effective against VIRAL infections

Question 28

What are suppressor or regulatory T-cells?

Answer 28

Treg

Also express CD4 but can also express protein Foxp3

These cells help to tone down immune response

Help prevent autoimmune diseases by turning off self-relative lymphocytes

Question 29

Learn the lymphatic system

Answer 29

Its only a few pages in the back if you have time