Chapter 16 - Innate Immune Defense Flashcards
What are three physiological processes that are responsible for innate immune defense?
pH, temperature & chemical receptor differences from plants/animals to humans
What is innate immune defense?
Our resistance to most plant an animal bacteria because of physiological processes
Are plant/animal bacteria a threat to humans?
Some can still cause disease
What is the first line of host defense?
(Non-specific)
Skin
Mucous membranes
Normal microbiota
What is the second line of host defense?
(Non-specific) Phagocytiotic white blood cells inflammation Fever Anti-microbial substances
What is the third line of host defense?
(Specific)
Specialized lymphocytes
B & T Cells
antibodies
Write a short note on the epidermis
Tightly compacted cells
Shedding removes potentially harmful microbes
Langerhans cells phagocytize pathogens
Write a short note on the dermis
Collagen protein fibers provide strength and flexibility to allow the skin to resist abrasions
What are two defensive properties of sweat & their effects?
Salt inhibits pathogenic growth
lysozymes destroy cell walls (PG) of bacteria
What is sebum?
sebaceous oil is secreted by the sebaceous glands that lowers the pH of the skin & keeps it pliable and less likely to crack or tear
What is the correlation between acidity and fungal infections?
The less acidic, or more alkaline, the environment, the less favorable it is to a fungal infection.
Write a short note on the mucous membrane
mucous membranes line every body cavity that is open to the air. The ciliary escalator traps microbes and transports them for destruction.
How are normal microbiota advantageous?
Normal microbiota secrete substances that limit pathogenic growth by changing the pH. Their familiarity with the host allows them to be the first consumers of nutrients. Normal microbiota also provide vitamin B12 and vitamin K. They stimulate 2nd line of host defense.
What are probiotics?
living bacteria in your gut that contribute to the health of your gut and digestive system by replenishing good bacteria after antibiotics, defending against pathogenic bacteria, and aiding digestion.
What are 4 chemical factors of the first line of immune defense?
Fungistatic fatty acids in sebum
low pH of skin
low pH of gastric juice
lysozymes in bodily fluids
What are the three types of formed elements in blood?
Erythrocytes, platelets & leukocytes.
Function of erythrocytes
carry O2 and CO2
Function of platelets
Blood clotting
Write a brief note on leukocytes
White blood cells that defend the body. Are composed of granulocytes & agranulocytes
What is an example of a granulocyte & what color does it stain?
Basophils stain blue with methyl blue
What are two examples of granulocytes & what color do they stain?
They phagocytize pathogens and are capable of diapedesis. Eosinophils stain red/orange with acidic eosin. Nuetrophils stain lilac with a mixture of acidic & basic dyes.
What does an increase in eosinophils indicate?
allergies and parasitic worm infections
What does an increase in leukocytes and neutrophils indicate?
bacterial infection
What does an increase in lymphocytes indicate?
viral infection
Write a brief note about phagocytosis
The quarterback of immune defense. wandering phagocytes and macrophages
Define pathogenicity
ability to cause disease
virulence
degree of pathogenicity
What are the 4 steps of bacterial infection
access, adherence, evasion, damage
What are the 2 ways bacteria can cause infection?
damage tissue or build up waste
What are the 4 portals of bacterial entry?
Mucous membrane, skin, conjunctiva, parenteral route (lesions)
What types of bacteria enter through the respiratory tract?
Colds, TB, pneumonia
What types of bacteria enter through the GI tract?
STD’s
What is a preferred portal of entry?
The portal of entry that gives a pathogen the highest virulence.
What is the ID50?
The virulence of a microbe - infectious dose for 50% of the population.
What is the LD50?
The potency of a toxin or a dosage that would be lethal for 50% of the population.
What are adhesions?
ligands that bind to receptors. If the adhesion can be altered, infection decreases
What are biofilms?
A community of microbes & their extra-cellular products that allow them to adhere & collet nutrients. They resist disinfectants and antibiotics.
What are capsules?
glycolax capsules increase virulence by impairing phagocytosis.
How does the immune system defend against capsules?
The immune system produces antibodies to phagocytize capsules.
What are two cell wall components that aid in virulence?
M protein allows heat and acid resistance. Waxy lipids (mycelic acid) resist digestion.
What are exoenzymes & what do they do?
enzymes excreted by bacteria that digest the immune response.
What is collagenase?
Collagenase is an extracellular enzyme secreted by bacteria to break down the collagen fibers in a host for the purpose of spreading disease.
What are IgA proteases?
IgA proteases are extracellular enzymes secreted by bacteria to destroy antibodies that defend against adherence.
What is antigenic variation?
The ability of bacteria to change its surface antigens.
In relation to virulence, what are invasions?
Invasions rearrange the actin filaments and cause membrane ruffling to allow bacteria into a host cell.
How does a bacteria use cell junctions to penetrate a host?
Junctions can be hijacked to move bacteria from cell to cell.
How do S. Pyogenes & S. Pneumoniae evade phagocytosis?
They inhibit adherence with M protein and capsules.
How do Staphylococcus aureus evade phagocytosis?
By killing phagocytes with leukocidins.
How does Listeriamonocytogenes evade phagocytosis?
By lysing phagocytes with their membrane attack complex.
How does signal evade phagocytosis?
Escapes from phagosome
How does HIV evade phagocytosis?
HIV prevents the fusion of phagosome and lysosome.
How does Coxiella brunette evade phagocytosis?
C. burnetti survives in phaglysosome.
What are the two ID cells that kill extracellularly?
Eosinophils & natural killer cells.
What are the two methods by which natural killer cells work extracellularly?
NK cells secrete toxins onto the surface of infected cells & differentiate normal body cells because they have similar proteins.
How does the complement system work?
the complement system increases the chance that phagocytes will eat invasive bacteria by attracting immune cells.
What is the end result of complement activation?
Complement activation results in the lysis of foreign cells. by introducing various proteins to work synergistically with the actions of antibodies.
What are the two ways the complement system can be activated?
The Classical and Alternate pathways can both activate the complement system.
Write a brief note on the Alternate pathway.
Independent of antibodies, properdin and lectin are released before antibodies are made.
Write a brief not on the three types of interferons.
Alpha, Beta, and Gamma interferons are released by an infected cell to warn neighboring cells. Cause many symptoms associated with viral infections. They work better at high temperatures.
What is the result of Alpha and Beta interferons?
Alpha and Beta interferons inhibit viral replication.
What is the result of Gamma interferons?
Gamma interferons cause the phagocytosis of bacteria.
Write a brief note on fevers.
Pyrogens trigger the hypothalamus to increase the body’s core temperature. phagocytosis of bacteria induces macrophages to produce IL-1, a pyrogen which triggers prostaglandin production in the hypothalamus. Followed by a shivering and crisis (break) phase.
What are the advantages of a fever?
Enhances IFN effects.
Inhibits growth.
enhances ID of some cells and tissue repair.
What are the disadvantages of a fever?
Death
Tachycardia in elderly
Increased metabolism
