33. Defence System Flashcards
Human Defence system function
Defends and fights against pathogens
Pathogen def.
A disease causing organism
Immunity def.
Ability to resist infection
Characteristics of general immunity
- Doesn’t produce any antibodies
- Non specific- acts on all pathogens
- Defends by stopping entry and attacking
Methods of general immunity
Barriers
- Skin-physically stops pathogens entering, has sebaceous glands which secretes sebum to kill bacteria
- Platelets prevent entry of pathogens if skin is broken by clotting the blood and forming a scab.
- Tears, Sweat and Saliva-enzyme lysozome attacks bacteria walls
- Acid- HCL in stomach kills pathogens
Methods of general immunity
Attack-WBC
- WBCs called phagocytes and monocytes carry out phagocytosis-where pathogen is engulfed by monocyte/phagocyte and killed
Methods of general immunity
Attack- Proteins
- Complement:produces holes in wall of pathogen causing it to fill with fluid and burst. (complimentary wafer thin mint-bursts)
- Inferon: Makes cells surrounding infected cell immune to viral pathogen, stopping spread of pathogen.
Methods of general immunity
Inflammatory response
Infected cells release chemicals causing capillaries to dilate, causing swelling, redness, heat.
Attracts WBCs to the area resulting in further inflammation and heat, restriction of reproduction of bacteria and viral cells as environment doesn’t support bacterial and viral growth.
Specific defence system def.
Part of our immune system that attacks particular pathogens
Specific defence system characteristics
Produces antibodies.
WBCs attack the pathogen
Attacks particular/specific pathogens
Antibody
biomolecule
produced by
attacks what
biomolecule: protein
produced by: lymphocyte
attacks antigens
Antigen def.
(g for germ)
Antigens are any foreign molecule that stimulates the production of antibodies.
eg. Bacterial cell walls, viral coats, foreign cells, cancerous cells
Specific defence system
Monocyte-how it defends
- Recognises and engulfs antigens-phagocytosis, develops into phagocytes/macrophages
- Displays these antigens on its surface stimulating antibody production
SDS Lymphocytes- T-type Where produced and matured types Once activated go to
Produced: Bone marrow
Matured: Thymus
Types: 4 (helper, killer, memory, suppressor)
Once activated go to: Lymphatic system
SDS Lymphocytes- B-type Where produced and matured types Once activated go to
Produced: Bone marrow
Matured: Bone marrow
Types: 2 (plasma, memory)
Once activated: Lymphatic system