10.1.1 Describe the process of clotting.

Clotting is the process through which the body prevents blood loss. Also known as coagulation, this process aids in the prevention of extreme blood loss due to the rupture of tissues, vessels and even organs, which, if is left without any clots (thrombus), could be fatal. This clotting process is comprised of platelets which circulate below the endothelial cells. When there is a rupture anywhere in the layer of these cells, the platelets , along with other clotting factors, eventually form a platelet plug, blocking the initial opening. The rupture in fact exposes certain tissue, primarily collagen and von Willebrand factor for example, that hadn't been exposed to the blood flow, are, allowing the platelets to attach to them and form this plug. This prevents blood from exiting the region, allowing the healing process (the regeneration of cells) to begin. Disorders in this system can lead to either an abundance of these platelets and multiple proteins (clotting factors) to be produced, or too few produced. The following demonstrates the entire process in 4 stages, known as the "Coagulation Cascade".

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Coagulation Cascade


Helpful Links:

http://www.med.uiuc.edu/hematology/PtClotInfo.htm
http://health.howstuffworks.com/adam-200077.htm (animation)
http://en.wikipedia.org/wiki/Coagulation

10.1.2 Outline the principle of challenge and response, clonal selection and memory cells as the basis of immunity.
A wide variety of B cells, cells of the immune system, inhabit the bone marrow. During clonal selection, antigens (molecules produced by pathogens that alert immune cells to their presence in the body) come into contact with the B cells, which have specific receptors for a variety of antigens. The ones most capable of destroying the pathogens are the ones with receptors able to recognize the antigens these pathogens produce. Those B cells whose receptors bind with antigens are selcted and made in multiple copies. These clones of B cells then divide further into plasma cells, which produce antibodies targeted to the pathogen and secrete them into the blood stream. Memory cells are produced as a response to encountering a specific pathogen. They live for a long time and are ready to destroy the antigen they are specific for and help prevent disease when encountered again.

10.1.3 Define active immunity, passive immunity, natural immunity, and artificial immunity.
Active immunity is immunity due to the production of antibodies by the organism itself after the body's defense mechanisms have been stimulated by invasion of foreign micro-organisms. Passive immunity is immunity due to the acquisition of antibodies from another organism in which active immunity has been stimulated, including via the placenta or in colostrum. 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 to the inoculation with vaccine.

10.1.4: Explain antibody production.
1. Macrophages absorb antigens by the process of endocytocis and they then attach them to membrane proteins called MHC proteins.
2. MHC proteins then carry the antigens to the macrophage surface by exocytosis. This is called antigen presentation.
3. A helper T cell with complementary antigen-binding domain as the antibody binds to the antigen on the surface of the macrophage which causes a signal to be passed from the macrophage to the helper T cell. This process, called the activation of the helper T cells causes the helper T cells to change from an inactive to an active state.
4. B cells with the antibodies complimentary to the antigens on the surface of the macrophage in their plasma membranes. These B cells bind to a complimentary activated T cell which sends a signal to the B cell, causing it to change from an inactive to an active state. This is called the activation of B cells.
5. B cells replicate to form clones of plasma cells which are active B cells with extensive networks of RERs (rough endoplasmic reticulum). The RER networks are used to synthesize large quantities of an antibody which is secreted by exocytosis.
6. Memory T and B cells are formed at the same time as activation and help protect the immune system from further attacks by the same antigen

10.1.5: Describe the production of monoclonal antibodies along with one use of them in diagnosis and one use in treatment.
1. Antigens are injected into an animal
2. Once immunity begins in the animal, B cells producing the desired antibody are extracted
3. Tumor cells are then obtained and made to replicate
4. The tumor and B cells are then fused to produce hybridoma cells that divide endlessly and produce the desired antibody
5. The hybridoma cells are cultured and the antibodies that are extracted and purified

Monoclonal antibodies are used to treat rabies since rabies tends to kill the infected human before the immune system has a chance to react to the infection. Monoclonal antibodies allow for the control of the disease until the immune system is able to produce its own antibodies.

Monoclonal antibodies are used to diagnose malaria since they can produce antigens that bind to the malarial parasites. Once the monoclonal antibodies are exposed to any suspected malaria antigens. Any bonded antigens are detected using more monoclonal antibodies with enzymes attached that cause a color change. This test is known as an ELISA test and can be used to measure the degree of infection as well as to distinguish between different kinds of malaria.

10.1.7 Outline the principle of vaccination.
  • A weakened or dead version of a pathogen is injected into the body, causing the immune system to mount a primary response.
  • This results in the production of B memory cells.
  • The B-cells "remember" the antibodies to produce in response to the pathogen.
  • When the real pathogen strikes, a secondary response occurs, aided by the memory cell production of pathogen-specific antibodies.
  • This response is much stronger than the primary repsonse and prevents any ill effects.

10.1.8 Discuss the benefits and dangers of vaccination against bacterial and viral infection, including the MMR vaccine (combined measles/mumps/rubella) and two other examples

The benefits of vaccination include:
1) Some diseases, such as small pox, can be eradicated
2) Deaths can be prevented, for example from measles
3) Long term disabilities can be prevented (rubella in pregnant women can lead to birth defects and mumps can cause infertility in men)

The dangers of vaccination include:
1) Excessive amounts of vaccination can reduce the ability of the immune system to fight off new diseases.
2) Immunity caused by the vaccination may not be as strong as immunity to the actual disease.
3) Dangerous side effects of some vaccines; whooping cough vaccine can cause brain damage, MMR vaccine may increase the chance of autism, and cancer patients and others can be harmed by cross infection from people vaccinated with the live virus.