week 7- immune system

Question 1

what are the 3 main components of immune system

Answer 1

-physicial barrier (skin)
-chemical barrier (saliva)
-Callular barrier (lymphocyte)

Question 2

what is another word for the skin

Answer 2

epidermis

Question 3

what does the epidermis do to kill unwanted pathogens?

Answer 3

secretes anti-microbial peptides t
it is also an impermeable barrier

Question 4

what is the role of mucous

Answer 4

to trap invading pathogens

Question 5

in the ciliated epidermis of the lungs, explain the process of an invading pathogen and its death.

Answer 5

-The ciliated epithelium of the lungs is a ciliated mucous membrane
- the mucous is to trap invading pathogens
-then the cilia (tiny hair-like coating) vibrate to push mucous up to the oesophagus
-it is then swallowed.

Question 6

give examples of second line of defence

Answer 6

saliva, stomach acid

Question 7

how can saliva kill pathogens

Answer 7

-contains Lysozymes, which can break down the cell wall of bacteria
- it also contains Immunoglobulin A, which can attach to an invading pathogen and inhibit its function

Question 8

how can stomach acid kill pathogens

Answer 8

Stomach acid is an extremely low pH, very acidic, which is an inhospitable environment for pathogens and they will die/breakdown/denature in thestomac

Question 9

describe the inflammatory response in the second line of defence

Answer 9

Injured cells secrete danger signals which cause mast cells to secrete histamines/prostaglandins that cause migration of immune cells to the site of injury
-Capillaries dilate to allow more fluid to the site of injury
-Pyrogens are released which increase temperature
-Pain receptors become activated
-White blood cells (phagocytes) migrate to the site of injury

Question 10

name signs of second line of defence

Answer 10

-Swelling
-Redness
-HeatPain
-Loss of function (sometimes – depends on locatio

Question 11

name functions of second line of defence

Answer 11

-Limit the spread of injury/infection
-Prevent further damage
-Dilute or remove harmful agents (Bacteria/Toxins)
-Remove damaged cells, tissue and debris

Question 12

what is third line of defence

Answer 12

cell-mediated immunity

Question 13

what does cell mediated immunity involve

Answer 13

the destruction of the bodies infected cells by cytotoxic T cells, and also destruction of pathogens by white blood cells(macrophages/neutrophils)
It also involves the release of cytokines (proteins that signal otherimmune cells

Question 14

describe antibody mediated immunity

Answer 14

the response to a specific pathogen, it involves the action of T helper cells which after activation with an antigen complement to B-cells
-these will then differentiate into plasma B cells which can produce antibodies against thespecific pathogen.
- These antibodies are released into the bloodstream and circulate around the body in large numbers, they target specific sites on the invading pathogen(antigen) and bind with it to prevent it from infecting cells

Question 15

what do memory cells allow

Answer 15

quicker response to thepathogen next time it is encountered

Question 16

what is the concept behind immunisation

Answer 16

prior exposure to an attenuated strain of a virus will allow the body to produce this immune response in a controlled manner, boosting the number of memory B cells that are then primed to respond to that particular pathogen

Question 17

what are primary organs of the immune system

Answer 17

-bone marrow
-the thymus

Question 18

name secondary organs of the immune system

Answer 18

-lymph nodes
-spleen
-lymph tissues
-Cutaneous Immune System

Question 19

what is the Cutaneous Immune System

Answer 19

Cutaneous Immune System,this is where mature lymphocytes can move around the body in order to respond to foreignantigens

Question 20

What prevents immune cells from killing self cells

Answer 20

Self markers (MHC)

Question 21

What does a heamotopio stem cell subdivide into

Answer 21

Lymphoid stem cell
myeloid progenitor

Question 22

How does a virus use a host cell

Answer 22

entering at taking over its replication process to create new virus cells

Question 23

Describe the cell response occurs once an infected cell has died from a virus (necrosis)

Answer 23

Killed cell will release signals to other cells
- this will stimulate nearby MAST CELLS to DEGRANULATE (release their granules)
- these granules are proinflammatory mediators (histamine) which are chemoattractors (attract immune cells to site of infection)

Question 24

How do capillaries respond to necrosis (a cell that has died) via virus

Answer 24

-dilate and become more permeable (leaky)
-this will allow more fluid and immune cells to the area
- surrounding tissues swell as proteoglycans hold onto extra fluid
-pressure build up stimulate pain receptors

Question 25

describe phagocytosis

Answer 25

Phagocyte engulfs invading pathogen into a phagaspme
Lysosomes secrete toxins and hydrolytic enzymes, killing pathogen.

Question 26

What cells present antigens, why?

Answer 26

Dendrites
Carry them around to find a T cell to take up the antigen

Question 27

When will a helper T cell become activated

Answer 27

After antigen presentation
Will become T helper cell or cytoxic T cell

Question 28

What occurs to a cytoxic T cell after activation

Answer 28

will identify infected cell
When identified will perform targeted cell death and kill the infected cell

Question 29

How is a virus neutralised

Answer 29

Body will be flooded by antibodies against a certain virus
antibody attaché to complimentary binding site on the virus antigen
It can no longer bind and gain access to a host cell

Question 30

What are B cells programmed to produce

Answer 30

antibodies specific to viral antigens