Unit 6 1. Why do you think specificity; heterogeneity (diversity), memory, and self-vs. Oneself recognition is vital to the immune system? 2. Define phagocytosis. How do some bacteria avoid or survive...

Unit 6
1. Why do you think specificity; heterogeneity (diversity), memory, and self vs. non-self
recognition is vital to the immune system?
Only because of Immune system, our body may respond against enemies (such as;
destructive molecules/ organisms) and thus; can protect itself. There are numerous properties
associated with immune system which make it efficient to deal with such big challenge for
instance; it can differentiate between self and non-self therefore; only reacts against foreign
entities. Further; it is able to recognize diverse type of molecules hence; can direct the
elimination of such harmful elements/ creatures that belong to different categories as;
carbohydrates, proteins etc.
In addition to above properties, it is also expected from immune cells that they will react
against antigens specifically and would remember such encounter (memory) as; such fight can
prove to be more effective than a non-specific one in context of rapid exclusion of detrimental
units. Both of above expectations are fulfilled via immune cells in a satisfactory manner. In this
way, all of above features can be termed „vital‟ for performance of immune system.
2. Define phagocytosis. How do some bacteria avoid or survive the action of phagocytes?
How does the phagocyte arrive at the site where it is needed? What happens to a phagocyte
after the majority of microorganisms and damaged tissue have been eliminated?
Phagocytosis may be described as; “the procedure via which a cell for instance; a White
Blood Cell (W.B.C) ingests microbes, other cells, and foreign elements.” Phagocytic cells may
arrive at the required site due to attraction caused by chemical substances which are released due
to immune response and such movement is known as; “chemo taxis”.
Though, the process of recognition and engulfment reflected via phagocytes is quite
effective yet, there are several microbes which could resist it for instance; Mycobacterium
tuberculosis and Legionella pneumophila may inhibit the fusion of phagosome and lysosome
which is essential for phagocytosis whereas; Trypanosoma cruzi and Shigella flexneri might lyse
the phagolysosomal membrane and can escape into the cytoplasm. In addition,
Mycobacterium leprae and Salmonella typhimurium can be found in phagolysosomal
compartment and may resist inactivation through lysosomal factors.
Finally, after elimination of maximum pathogens and completion of phagocytic cell‟s life
spawn, it can die due to its own digestive components.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&ved=0CCsQFjAB&url=http%3A%2F%2Fen.wikipedia.org%2Fwiki%2FLegionella_pneumophila&ei=DhKTUOywL_G4iAev74CoBg&usg=AFQjCNG6b3XBvm2bnK1pldiqCltCHgpU8g&sig2=Tn36SzpgNqNu9u_esoXOvw
https://www.google.com/search?hl=en&pwst=1&site=webhp&spell=1&q=Trypanosoma+cruzi&sa=X&ei=JxOTUJ6TOamTiAfokID4DQ&ved=0CB0QvwUoAA
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCAQFjAA&url=http%3A%2F%2Fmicrobewiki.kenyon.edu%2Findex.php%2FShigella_flexneri&ei=QROTUOP4E4SQiQeexYDYCg&usg=AFQjCNH16m8f8Uytew8ciCv_KVZ5VFR8zQ&sig2=XEP-orXbj3_BUXKmLyVr9Q
https://www.google.com/search?hl=en&pwst=1&site=webhp&spell=1&q=Mycobacterium+leprae&sa=X&ei=VBOTUPTXFeb9iAfW3oGgBg&ved=0CB0QvwUoAA
https://www.google.com/search?hl=en&pwst=1&site=webhp&spell=1&q=Salmonella+typhimurium&sa=X&ei=YxOTUPaaD8eWiQf6uYDYAg&ved=0CB0QvwUoAA

3. The "cliché" "an ounce of prevention is worth a pound of cure" means that preventing a
disease is less costly economically and to the health of the host than treating the disease
once it has occurred. Draw a flow chart (or list) showing the connections between
reservoirs of infection; modes of transmission; host susceptibility factors, and portals of
entry. These are the steps in the disease cycle that precede the infection of the host. Are
there ways of preventing host infection by halting the pathogen at these points? Discuss
each step, and what measures can be used to eliminate the treat of potential disease at each
point.
Chain of Infection
Reservoirs
Humans, Animals and
Environment
Modes of Transmission
Direct
1. Direct contact
2. Droplet spread
Indirect
1. Airborne
2. Vehicle borne
3. Vector borne
(mechanical or
biological)
Portal of Entry
1. Oral route
2....