Non-Specific Immune Response Flashcards
What do tears contain?
An enzyme called lysozyme.
How does Lysozyme kill bacteria?
Lysozyme kills bacteria by breaking down their cell walls
Where is the enzyme also found?
In nasal secretions and saliva
What is the purpose of Lysozyme?
Protect body from harmful bacteria we breathe or the food we eat.
What happens when someone sustains an injury?
Microbes enter the body.
What helps seal a wound?
A blood clot.
What is inflammation at the site called?
An inflammatory response.
What does an inflammatory response help do?
Helps destroy invading microbes
What do damaged WBC + mast cells release?
Chemicals and Histamine
What do the chemicals released by WBCs and mast cells do?
Chemicals cause arterioles in the area to dilate, increasing blood flow in the capillaries at the infected site.
What does Histamine do to the capillaries?
Histamine increases the permeability of the capillaries: cells in the capillary walls separate slightly=vessels leak.
What substances leak from vessels?
Plasma fluid, WBC, antibodies leak from blood into the tissue.
What does the leaking of plasma fluid, WBC and antibodies cause? What can this result in?
Odema (swelling). Microbes can now be attacked by these intact white cells.
What are Phagocytes?
Phagocytes are WBC that, engulf bacteria + other foreign matter in blood + tissues
What do Phagocytes include?
Phagocytes include: neutrophils + macrophages
Neutrophils
- Leave blood capillaries by squeezing the cells of capillary walls
- Ingest + destroy bacteria
- Last a few days
Lymphocytes
- Two types: B cells + T cells
- Involved in immune response: antibody production + immunity
- Can survive for a few days or few years
Monocytes
- Circulate in the blood for a day or two before they move into the tissue by squeezing between the cells of the capillary walls
- Here they become macrophages + engulf bacteria
Present in: lungs, liver, kidneys, spleen + lymph nodes
Other White Blood Cells
Produce chemical histamine involved in the inflammatory response.
WBC
All contain a nucleus
RBC
No nucleus. Transport oxygen and some CO2
Platelets
Platelets: Cell fragments involved in blood clotting.
ACTION AT THE INFECTED SITE: What do the chemicals released by bacteria and cells damaged attract?
Phagocytic white cells.
What white blood cell is first to arrive?What do they do?
Neutrophils are first to arrive and engulf bacteria and become inactive and die.
After the neutrophils die what is it then followed by?
Macrophages which are larger and longer lived cells
They destroy more bacteria than neutrophils
Then ingest debris from damaged cells.
Where is the ingested material enclosed? How is the lysosome involved?
- Ingested material is enclosed in a vacuole
- Lysosome containing digestive enzymes fuse with the vacuole
- Enzymes are released + destroy bacteria
Stages of Neutrophils/Macrophages destroying Bacteria
- Bacteria with antigens on surface.
- Engulfed by neutrophil or macrophage
- Enclosed in vacuole
- Lysosomes fuse with vacuole, releasing enzymes that destroy foreign material.
ACTION TO PREVENT THE SPREAD OF INFECTION: Where do some bacteria go? How can it be stopped?
Some bacteria get carried by the blood or the lymph
Spread of this bacteria can be stopped by the action of macrophages in the lymph nodes, spleen + liver
What happens when the lymph system fails?
When the lymph system fails the body goes into septic shock.
Role of lymph nodes in the lymphatic system
- Tissue fluid drains into the lymphatic vessels.
- Lymph (fluid) flows through lymph vessels + passes through lymph nodes: returns to blood via lymphatic + thoracic duct.
- As lymph passes through the lymph nodes, any pathogen present activate lymphocytes + macro phages then destroy the microbes.
ANTIMICROBIAL PROTEINS (INTERFERON): What protein is the only non-specific defence against viruses?
Interferon.
Where is interferon produced?
Virus infected cells produce this protein and it diffuses to the surrounding cells.
What does interferon do?
Prevents viruses from multiplying
Inhibits viral protein synthesis
Limits formation of new virus particles.
