Immunity

Question 1

what is the first line of defence?

Answer 1

the skin

Sebaceous and sweat glands can help wash away micro organisms.

Question 2

Two examples of free macrophages

Answer 2

Kupffer cells
alveolar macrophages (phagocytic dust cells)

Question 3

What to NK cells do?

Answer 3

surveillance. Attack any membrane with non-self antigens.

Used to fight cancer.

Question 4

what are interferons?

Answer 4

proteins made by host cells in response to pathogens such as viruses, bacteria, parasites or tumor cells.
Released from virally infected cells to communicate to other cells to trigger the production of antiviral proteins in the cytoplasm.
Antiviral proteins interfere with viral replication within the cell.
Also ; stimulate other NK and macrophagic cells.

Question 5

What does the complement system do?

Answer 5

• stimulates inflammation by enhancing the release of histamine from basophils and mast cells.
• attracts phagocytes to the area.
• coats antigens and makes them easier for phagocytosis
• MAC (membrane attack complex) creates pores in the antigen for destruction

Question 6

what is opsonization?

Answer 6

the marking of an antigen ready for ingestion via a macrophage.

Question 7

name all the non specific immune defences (7)

Answer 7

physical barriers
phagocytic cells
immunological surveillance
interferons
complement
inflammation
fever

Question 8

what is immunological surveillance?

Answer 8

the constant monitoring of normal tissues by NK (natural killer) cells.

Question 9

How do NK cells work?

Answer 9

attack any cells with non-self recognition proteins on the membrane. They can attack ;-
bacteria in interstitial fluid,
body cells infected by viruses,
cancer cells.

Question 10

The term complement refers to the fact that it …….. the immune system

Answer 10

complements

complements are proteins that attach onto the pathogen, most important is c3b

Question 11

what is inflammation?

Answer 11

it is a localised tissue response to injury

Question 12

Inflammation causes …. (7)

Answer 12

1. increase in blood flow
2. activation of phagocytes
3. increase in capillary permeability
4. activation of complement
5. clotting reactions
6. increase in local temperature
7. activation of specific defences

Question 13

what do mast cells release into the interstitial fluid that creates inflammation?

Answer 13

heparin
histamine
prostaglandins

Question 14

what is the difference between mast cells and basophils?

Answer 14

mast cells are found in the connective tissue, basophils are found in the blood (but can then move into the connective interstitial fluid). Both release heparin and histamine.

Question 15

What does histamine do in an immune response?

Answer 15

increase capillary permeability and accelerate blood flow into the area.

Question 16

what does an increase in blood flow create, in an immune response?

Answer 16

reddening, increase in temperature, increase in enzymatic reactions, increase in phagocytic activity, possible denaturing of foreign proteins/ enzymes.

Question 17

chemotaxis attracts…….

Answer 17

neutrophils

Question 18

what is diapedesis?

Answer 18

the outward passage of blood cells through intact vessel walls (during an immune response)

Question 19

what do neutrophils generate to kill engulfed pathogens?

Answer 19

nitric oxide, and hydrogen peroxide.

This attracts more neutrophils and other macrophages.

Question 20

what are phagocytes?

Answer 20

generic term for cells that engulf pathogens

Question 21

what helps attract neutrophils into an area?

Answer 21

chemotaxis.

Question 22

What are cytokines?

Answer 22

Cytokines are important in cell signaling - they are released by cells and affect the behavior of other cells.
Cytokines include interferons, interleukins, tumour necrosis factor but generally not hormones or growth factors. Cytokines are produced by broad range of cells, including immune cells like macrophages, B lymphocytes, T lymphocytes and mast cells.

Question 23

what attracts lots more macrophages into an area?

Answer 23

the secretion of cytokines by neutrophils.