2 Topic 10.1 - Types of Defense Describe the process of clotting.Clotting factors are released from platelets (incomplete fragments of cells without a nucleus) and damaged cells nearby the injury or opening, resulting in the formation of thrombin.
3 Thrombin catalyzes the conversion of plasma-soluble fibrinogen, which isalways present in the bloodstream,into the fibrous protein fibrin whichcaptures red blood cells andimmobilizes the fluid portionof blood.
4 This converts the once-fluid blood to a gelatin-like mass. Platelets then enter this fibrous mass andsend out sticky extensions to one another.The platelets then contract, forcing outthe liquid andscabbing over the wound.
5 10.1.2 Outline the principle of challenge and response, clonal selection and memorycells as the basis of immunity.A wide variety of B cells, cells of theimmune system, inhabit the bone marrow.During clonal selection, antigens (moleculesproduced by pathogens that alert immune cellsto their presence in the body) come intocontact with the B cells, which have specificreceptors for a variety of antigens.
6 The ones most capable of destroying the pathogens are the ones with receptorsable to recognize the antigens thesepathogens produce. Those B cellswhose receptors bind with antigensare selcted and made inmultiple copies.
7 These clones of B cells then divide further into plasma cells, which produce antibodies targetedto the pathogen and secrete them into the bloodstream. Memory cells are produced as aresponse to encountering a specific pathogen.
8 They live for a long time and are ready to destroy the antigen they are specific forand help prevent disease whenencountered again.
9 10.1.3 Define active immunity, passive immunity, natural immunity, and artificial immunity.Active immunity is immunity due to theproduction of antibodies by the organism itselfafter the body's defence mechanisms havebeen stimulated by invasion offoreign micro-organisms.
10 Passive immunity is immunity due to the acquisition of antibodies from anotherorganism in which active immunity hasbeen stimulated, including via theplacenta or in colostrum.
11 Natural immunity is immunity due to previous infection by a pathogen and the subsequent.cell memory of the method of its eradication.Artificial immunity is immunity due tothe inoculation with vaccine.
12 10.1.4 Explain antibody production Macrophages consume bacteria with antigenmolecules in their membranes. They thenpresent these antigens on their ownmembranes with the help of specialprotein structures.
13 When helper T-cells come into contact with macrophages, they pick up these antigensand incorporate them into their own proteinstructures, which they use to present theantigens to B-cells.
14 These antigens activate helper T-cells to activate B-cells by passing their antigen to B-cell receptors. The B-cellthen divides to form clones of antibodysecreting plasma cells and memory cells.
15 10.1.5 State that cytotoxic T-cells destroy cancer cells and body cellsinfected with viruses.Cytotoxic T-cells destroy cancer cellsand body cells infected with viruses.
16 10.1.6 Describe the production of monoclonal antibodies; one use of them indiagnosis and one use in treatment.Monoclonal antibodies are named so becausethey are the product of a single cloningof cells and are all exactly identical. Mostimmune reactions are polyclonal and oftenproduce antibodies that are not specificenough to fight diseases when takenout and injected into other persons or animals.
17 To produce monoclonal antibodies, a polyclonal mix of B-cells is placed in a medium filled with myeloma,or tumour cells, in conditions that favor fusionbetween the tumor and B-cells. The resultingfused cells are called hybridomas. They arethen placed in a medium in which only thehybridomas survive.
18 Only the hybridomas that produce the correct antibodies are cultured; the resulting antibodiesare then taken up. Detection of antibodiesto HIV is one example in diagnosis. Others aredetection of a specific cardiac isoenzyme insuspected cases of heart attack anddetection of HCG in pregnancy test kits.
19 Examples if the use of these antibodies for treatment include targeting of cancer cellswith drugs attached to monoclonal antibodies,emergency treatment of rabies or cancer,blood and tussue typing for transplantcompatibility and purification ofin dustriall made interferon
20 10.1.7 Outline the principle of vaccination. Vaccination is when you inject a weakenedor killed version of a pathogen into thebody, which causes the immune systemto mount a primary response.
21 The resulting immune response results in the production of B memory cells,which can then "remember" the antibodiesto produce in response to the pathogen.
22 When the real disease strikes, the secondary resonse occurs, aided by the memory cellproduction of pathogen-specific antibodies.This is much stronger than the primaryresponse and prevents the appearance ofany ill effects by the pathogen
23 10.18 Discuss the benefits and dangers of vaccination against bacterial andviral infection, including MMR vaccine(combined measles/mumps/rubella)and two other examples.There have been vaccinations made formany viral and bacterial diseases. Onceviral diseases are contracted, it is difficultto effectively treat them. Bacterialdiseases can often be treated with antibiotics.
24 The measles, mumps, and rubella vaccine (MMR) is given in early childhood and for females, it mustbe given at child-bearing age when not pregnant.For tetanus, a vaccine is given when the child is14-16 years old with a booster every ten years.
25 For influenza, a vaccine is given for chronically ill people, mainly with respiratory diseases,or for healthy people over 65 years old. The maindanger of vaccinations comes from thefact that if the bacteria or virus usedin the vaccines has not been weakenedenough, they can still infect theperson they are injected into.
26 If this is an especially dangerous or deadly disease, it can be fatal to the vaccinatedsubject. An example of this came in theArmy's use of the anthrax vaccine on itstroops. In several cases, the anthrax usedwas not fully weakened, and it hassince caused averse but not deadlyreactions in many soldiers.
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