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The International Encyclopedia of Primatology - PDF

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Added on  2021-06-15

The International Encyclopedia of Primatology - PDF

   Added on 2021-06-15

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Please provide answers to the following questions. Some of the answers needs to be referenced in text and create a reference list.Questions:1-Name two routes of entry for pathogenic organisms1.Faecal oral route usually from an infected person or contaminated food.2.Droplet contact from coughing and sneezing from an infected person.2-Describe what mechanisms the body uses to prevent organisms it encounters for the first time from causing disease. (just 6 lines) with referenceIntact skin acts as a physical barrier to prevent entry of microorganisms. Mucus, broom like action of cilia and flushing action of tears saliva and diarrhoea acts as mechanical barriers to entry of microorganisms. Also secretions like sebum and cerumen, low PH of urine, gastric juice, urinary and vaginal tract and lysozymes all act as chemical barrier against microorganisms. Phagocytic cell such as macrophages, neutrophils and dendritic cells engulf and digest microorganisms. Secretory cells such as eosinophils, basophils and mast cell also play a role. (Falkow, 2007.).3-Provide a labelled diagram to illustrate a neutrophil killing a bacterium by phagocytosis (reference the picture)(Gordon 2016)4-Explain the process of phagocytosis of an invading organism by a macrophage and the subsequent of antigen presentation. (6 lines)Macrophages recognise certain structures which are present in microorganisms but not in human cells(PAMPs) such as peptidoglycan and flagella. Then it engulfs the microbe by endocytosis and produce molecules such as reactive oxygen species, lysozyme and nitric oxide which helps in phagocytosis. Inflammation then result through production of pro-inflammatory cytokines such as TNF, IL-1 and chemokines. Adaptive immunity is then activated through antigen presentation by use of MHC molecules.5-Give a brief overview of the role of the major histocompatibilityMHC is a cluster of genes present in all mammals. It is found in chromosome 6 in humans and plays a role in discriminating between self and non-self antigens. Also in antigen processing and presentation.
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6-Fill in the following table of donor-recipient compatibility in the ABO blood group system, using ticks and crosses to indicate compatibility and non-compatibility, respectively, for a donation of one or two units of whole blood. DONOR0ABABRECIPIENTOABAB7-Explain why some transfusions are safe one way round but if the same donor-recipient pair are reversed (i.e. donor becomes recipient and vice-versa) there is likely to be an agglutination reaction. (5 lines)Many have RH factor on the surface of red blood cells. Those who have this antigen are called Rh+ and those without are Rh-. Rh- people do not have rhesus antibodies naturally in their blood plasma. When a Rh+ receives blood from a Rh- there is no agglutination but when a Rh- receives blood from a Rh+ agglutination occurs because rhesus antigen can trigger production of rhesus antibodies in the person with Rh- blood.8-What happens if you transfuse a large volume of blood from a compatible donor (according to the previous table), but with a different blood type? (4 lines)There is no antigen-antibody reaction that will occur hence there is no transfusion reaction islikely to occur but transfusing large volume of fluid may lead to fluid overload which may result to pulmonary oedema and acute respiratory failure. 9-Use this principle to predict whether blood donors who are positive for Rhesus factor (D-antigen) cab donate small quantities (10r 2 units) of whole blood to Rhesus negative recipients or vice-versa. (8 /10 lines) Rh positive person can donate to the Rh negative blood person only if it is for the first time. Since Rh- blood person does not have Rh antibodies naturally in their blood plasma there is likely to be no immediate danger. But on subsequent transfusion there will be severe transfusion reaction as the Rh- individual has been initial exposed to the Rh antigen and has developed antibodies against it hence agglutination will occur. A Rh- individual can donate toboth the Rh+ individual or Rh- individual without any adverse transfusion reaction occurring.This is because there is no antigen antibody reaction against the Rh antigen.10-Draw a chart to illustrate the titre (relative concentration) of specific antibodies in the blood of a patient who has been challenged with a microorganism once, and then again with the same organism at a later date.
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11-Explain the shape of this curve in terms of the role played by B and T memory cells. ( 15 lines ) The amount of antibodies produced during first infection is lower than during re-infection. This isbecause during first infection the antigen after being phagocytosed it is presented to T cells which undergo clonal expansion to produce B cells specific to the same antigen. Most of it form plasma cells which produce first antibodies which clears the infection. A fraction of it persist on along term basis as dormant memory cells and undergo mutation and selection. These B cells thathave undergone mutation have high affinity surface immunoglobulin and hence recognises antigen better. On second infection or re-infection the number of B cells clones increase producing a polyclonal response hence a stronger antibody response. This increased antibody titre and its affinity helps to clear infection faster than first infection. This is usually observed in secondary immune response. This explains why contracting such diseases as chicken pox for the first time signs and symptoms can be so severe and there after they gain immunity against the disease or symptoms may be mild. 12-Explain the concept of ‘Herd Immunity’ and use it to comment on the rise in recorded deaths from measles following the campaign by Andrew Wakefield to persuade the public that MMR vaccine is linked to autism. (15 lines) Herd immunity is when a portion of the population is vaccinated enough to provide protection to the rest of population not vaccinated against the disease. Andrew Wakefield and 12 of his colleagues in 1998 published a case series in Lancetsuggesting that the measles, mumps and rubella vaccine may predispose autism in children. This received wide publicity and the MMR vaccination rates began to drop because parents were worried about risk of autism after vaccination. Andrew’s claims however were proven unfounded. Following this, there was massive rise in measles epidemic outbreaks and most cases, the deaths were linked to people were not vaccinated. This therefore, shows that the anti-MMR campaign by Andrew Wakefield interrupted the Herd Immunity which lead to most children mot being immunised against the disease. Whenever there was measles outbreak therefore those not immunised were affected.13-Give a definition of the term pathogen (5 lines)
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