Immune Response & Defence Against Disease (PPT 6-8) [U2/ T2] Flashcards
(NOT COMPLETE)
What are the body’s two types of defence?
1) Nonspecific (innate)
2) Specific (acquired)
What does the 1st line of defence include?
- Intact skin
- Mucous membranes & their secretions
What does the 2nd line of defence include?
- Phagocytic white blood cells
- Inflammation and fever
- Antimicrobial substances
- Natural killer cells
What does the 3rd line of defence include?
- Specialized lymphocytes
- Antibodies
What are the characteristics of an Innate system?
- Present before any exposure to pathogens and is effective from the time of birth
- Nonspefic (responses to pathogens both externally & internally)
- Comprise of barrier systems to prevent microbial attack & entry
- Comprise of nonspefic chemicals and cells that attack foreign material.
- Located in both plants and animals
Name the structure and function of the skin
S- Covers the whole body.
F- Protection from physical damage, microbe infection & dehydration.
Name the structure and function of the epithelial cells
S- Line the cell
- Joined very tightly
F- Produce mucus and have cilia
Name the structure and function of the mucus & cilia
S-
F- Sweep mucus & entrapped microbes out
Name the structure and function of the secreations (tears, saliva, sweat, stomach acid)
S- Contain lysozyme enzymes & other toxic metabolisms
F- Sweat creates a poor environment for bacterial growth due to high salt content
- Very low pH
What do the signalling molecules and complement system do?
- Coordinate the immune response
- Released from body cells to communicate with the immune system
- Singal presence of cell damage or invader by releasing signalling chemicals
- Promote growth & proliferation of lymphocytes WBC, induce fever, promote 3rd line of defence, activate macrophages & initiate inflammation.
- Chemicals synthesized y damaged cells act locally & break down quickly.
What does the complement system do?
- Made up of 30 proteins
- Circulate in the bloodstream inactivly, will be activated as 2nd defense
- Activated by non-self markers on antigens, bacteria & parasites.
- They mark the antigens for destruction by adhering to them.
- Some are enzymes that attach to bacteria & make them burst
- Some trigger inflammatory response
- Act as messengers to control blood flow
- Activate inflammatory response which causes pain.
What is the role of defensive cells?
- Special white blood cells seek & destroy antigens.
- All engluf foreign invaders & dead or injured cells.
- Help coordinate immune response by releasing cytokines to signal molecules to activate phagocytes
- Closure of breach to minimise invasion
- Stop blood loss
- Platelets & fibrin create fibrin mesh to plug the hole and restore skin barrier.
Why does the body induce fever to fight infections
- Body releases chemicals to alter thermost increasing the body temperature
- Temperature increase has a positive effect of healing, a negative impact on invading microbes.
What is the function of the cuticle in plants as a barrier system.
F-
What is the function of the bark in plants as a barrier system
F-
