failing control of the immune system

Question 1

MHC molecules vary across the population.

what are the only people with truly identical MHC molecules?

Answer 1

identical twins
there are thousands of different combinations in the human popualtion. MHC molecules will prevent the adhesion of the virus to the target cell

Question 2

why do MHC molecules vary across the popualtion?

Answer 2

i dont really know until next year, but it prevents bugs subverting MHC

Question 3

what is autoimmune disease?

Answer 3

• its when the immune system attacks the body’s own tissue and cells
• in each case, the tolerance of some self-antigen is overcome- Ab and/ or cytotoxic cells become activated

Question 4

what are some examples of autoimmune diseases?

Answer 4

Multiple sclerosis (MS)- the meylin is attacked 
myasthenia gravis- acetlycholine receptors on skeletal muscle cells are attacked
type 1 diabetes- insulin producing cells are destroyed
rheumatoid arthritus- joints are attacked

Question 5

what are the treatment options for autoimmune diseases?

Answer 5

the treatment options are to treat symptoms or supress the immune system [but only to the problem antigen]

Question 6

what are the main factors affecting immune performance?

Answer 6

• lyfestyle and nutrition
• transplants and immunisations
• allergies
• AIDS

Question 7

how can lifestyle and nutrition affect immune performance?

Answer 7

protein-calorie malnutrition- the single greatest contributor to decreased resistance to infection globally
psychoneuroimmunology- the immune system can alter neural and endocrine function
cortisol- a hormone associated with stress which can have a suppressive effect on inflammation and specific immunity
effect of physical exercise- this is debated but moderate exercise is thought to help immune performance

Question 8

how does transplants and immunisations have an effect on immune performance?

Answer 8

• in transplants, graft rejection is a major problem and cytotoxic t-cells and helper t-cells are involved, and patients are given immune function supressing drugs

Question 9

how does transplants and immunisations have an effect on immune performance?

Answer 9

• in transplants, graft rejection is a major problem and cytotoxic t-cells and helper t-cells are involved, and patients are given immune function suppressing drugs
• in blood transfusion reactions involve antibiotics, erythrocytes lack MHC but have more than 400 antigens, blood type is based on the antigen on the surface of the ethrocyte.

Question 10

what is a universal recipient in terms of blood type?

Answer 10

people with AB blood can have any type of blood since they don’t have antibodies to A or B

Question 11

what causes blood type?

Answer 11

its based on the antigen on the surface of the ethrocyte

type A has A antigens and type O has no antigens, hence why it can be give to anyone

Question 12

how do allergies affect immune performance?

Answer 12

the immune response to environmental antigens causing inflammation and damage to bidy cells

Question 13

how do allergies affect immune performance?

Answer 13

the immune response to environmental antigens causing inflammation and damage to body cells
most allergens are harmless, the risk is the immune response
there are 2 types of immune responses- delayed hypersensitivity and immediate hypersensitivity

Question 14

what is delayed hypersensitivity?

Answer 14

its when the reaction takes several days to develop e.g. poison ivy or like my penicillin allergy

Question 15

what is immediate hypersensitivity?

Answer 15

after the initial exposure, IgE antibodies attach themselves to mast cells
subsequent exposures cause mast cells to release inflammatory mediators including histamine
this includes mucus secretion, increased blood flow, swelling of epithelial lining and contraction of smooth muscle around the airways
the response produces congestion, runny nose, sneezing and difficulty breathing

Question 16

how does AIDS affect immune performance?

Answer 16

its caused by the human immunodeficiency virus (HIV)
preferentially infects helper t-cells and uses CD4 as a receptor for virus entry
cytotoxic t-cells kill infected helper t-cells other uninfected helper t-cells die by apoptosis, without adequate helper t-cells, neither b-cells or cytotoxic t-cells function normally
death is usually from oppertunistic infections that a normal immune system would fight off
its a growing pandemic with about 15,000 new infections a day