Human Defence Flashcards
What are pathogens/pathogenic?
Microorganism that cause disease
Give exmpled of bacterial pathogens
1)Tetanus
2)syphilis
3)streptococcus
Give examples of fungal pathogen?
1)Ringworm
2)Athletes foot
Give examples of viral pathogens
1)chicken pox
2)HIV
What is the human defence split into?
1)General defence system
2)Specific defence system
What is the general defence system?
ALL pathogens
What is the specific defence system?
Lymphocytes produce antibodies to target SPECIFIC pathogens
What is the first line of defence in human defence?
1)Acid
2)mucous membranes and cilia
3)clotting
4)skin
Where is acid found in the human defence system?
1)hydrochloric acid in the stomach
2)lactic acid in the vagina
How does acid act in the human defence system?
Low pH of the acid will denature enzymes of pathogens
How does mucous membranes and cilia work in the general defence system?
1)trachea in respiratory tract
2)oesophagus in the digestive tract
How does mucus and cilia act as a physical barrier?
Trapping pathogens
How does clotting act in the general defence system?
Blood clots to prevent pathogens from entering
How does skin act in the general defence system?
1)physical barrier
2)harmless bacteria provide competition
3)sebaceous glands secrete sebum killing bacteria
Is skin permeable or impermeable?
Impermeable
What is the second line of defence system?
1)Monocytes
2)inflammation
3)fever
4)defence proteins
How do monocytes/phagocytes work in the second line of defence system ?
Surrounds,engulfs and digests pathogens
What are macrophages?
Monocytes/phagocytes that remain fixed in areas such as spleen and appendix
What is the function in macrophages?
Pathogens in lymph
How does inflammation work in the second line of defence?
1)Infected cells release histamine causing blood vessels to open wider
2)brings more monocytes to area
3)causes redness,swelling, and pain
What are antihistamines?
They stop the effect of histamines
In what case do you take antihistamines
Taken in the case of allergies
How does fever act in the second line of defence
Body temperature rises above 37 degrees making it more difficult for pathogens to reproduce
What type of defence proteins are there in the second line of defence?
1)complement proteins
2)interferons
What are interferons in the defence proteins?
Cells are more resistant to viral infections
What is the second line of defence?
Once pathogens are in the blood
What is the first line of defence?
Stops pathogens getting into the blood
What are lymphocytes
White Blood cells
Where are all lymphocytes produced
Bone marrow
What are the two types of lymphocytes?
1)b-cells
2)t-cells
Where do B-cells mature?
Bone marrow
Where do t-cells mature?
Thymus gland
What are the two types of b-cells?
1)Plasma B-cell
2)memory b-cells
What are the four types of t-cells
1)Helper T cells
2)killer T-cells
3)suppressor T-cells
4)Memory t-cells
What are b-lymphocytes (Plasma B-cells)
White bloods cells that target pathogens by releasing a specific antibodies after antigens are recognised as being foreign
What is an antigen?
Foreign molecule on the surface of a pathogen that stimulates B-lymphocytes to produce a specific anti-bodies
What is an antibody?
Protein produced by a B-cell in response to recognising an antigen
Outline the role of b-cells in disposing the body of a specific pathogens
1)Antigens recognise b-cells and release specific antibody
2)antibodies lock onto antigens and clump pathogens
3)marked for digestions by monocytes
The antigen/antibody reaction is a very specific reaction. What does this mean?
1)very precise fit between shape of antigen and antibody
2)each antigen stimulates antibody
What is the role of memory b-cells in the human system
1)B-cells that remain in the body after the pathogen has been disposed off
2)same pathogen enters the body memory b-cells produce a large number of antibodies very quickly
Explain how adults may not be as susceptible or new infections?
Adults are most likely to have suffered from a similar infection and will have memory b-cells
Give two problems associated with the antibody and antigen reaction
1)antibodies against its own tissues
2)allergies
What are helper t-cells?
1)Recognise antigens as being foreign
2)stimulate the production of b-cells and killer t-cells
What is the role of b-cells I’m the human defence system?
Release specific antibodies
What is the role of killer t-cells?
Attack infected body cells (releasing perforin)
What are suppressor t-cells
Turn of immune response once pathogen is destroyed (stop b-cells and killer t-cells)
What is the role of memory t-b cells
Remain in body and recognise and release antibodies very quickly against the same pathogen if it enters
What is induced immunity?
Ability to resist disease
What are the two types of immunity?
1)Active immunity
2)passive immunity
What is active immunity?
Production of a persons own antibodies in response to antigens
What are the two types of active immunity?
1)natural
2)artificial
What is natural active immunity?
1)A person gets sick b-cells produce a specific antibody
2)B-cells remain in body as memory cells
What is artificial active immunity?
1)A person gets a vaccination
2)stimulates b-cell production and release specific antibody
3)lymphocytes remain in body as memory cells
What is the duration of active immunity?
1)Long term immunity
2)B-cells remain in body as memory cells
3)same pathogen enters b-cells produce many antibodies very quickly
What is a vaccination?
1)Non-disease casing dose of a pathogen
2)Stimulate production of specific antibodies form b-cells
3)b-cells remain as memory cells and person has long term active immunity
Who are most at risk of mmr?
Babies under 12 months and unvaccinated people are at most risk
Why might people be concerned about getting a vaccine
There is a part of a pathogen
What is the point of a booster vaccine?
Strengthens first treatment
1)increasing antibodies
2)more quickly
Immunity that results from a vaccination is effectively the same immunity that develops following an infection ?
True
1)both cause b-cells to produce a specific antibody
2)both result in memory cells in body giving long term active immunity
What is passive immunity?
Antibodies introduced into the body
What are the two types of passive immunity?
Natural and artificial
What is natural passive immunity?
Antibodies passed across placenta or breast milk to her baby
What is artificial passive immunity?
Person given an injection containing antibodies made from another organism
Example of passive artificial immunity
Tetanus injection
In what situation are tetanus antibodies given instead of a tetanus vaccine?
1)Person is in Immediate danger
2)Already thought to be infected
Why do you think the rabbit population was decimated when the myxoma virus was brought to Ireland?
1)Rabbits have no immunity
2)they did not have b-cells to produce specific antibodies
Suggest a reason why the virus is mo longer a major threat to rabbits in related?
1)Rabbits have evolved immunity
2)Have b-cells to produce specific antibodies against the virus
HIV and AIDS can decrease human populations true or false?
No- HIV is not decimating propulsion and we understand how to stop the spread of it
