mini mock topics Flashcards
What does the non-specific defence system do?
The non specific human system works to prevent pathogens from entering the body.
What are the different non specific defence systems?
Skin, nose, trachea and bronchi and the stomach
What are the skin defences?
The skin covers almost all parts of your body to prevent infection from pathogens. If it is cut or grazed it immediately begins to heal itself, often by forming a scab, which prevents infection as the skin acts as a physical barrier. Parts of the body that do not have skin have developed other ways to prevent infection. For example, the eyes produce tears, which contain enzymes, and these are chemical barriers.
- Your skin produces antimicrobial secretions to destroy pathogenic bacteria.
- Healthy skin is covered with microorganisms that help keep you healthy and act as an extra barrier to the entry of pathogens.
What are the nose defences?
The nose has internal hairs, which act as a physical barrier to infection. Cells in the nose produce mucus. This traps pathogens before they can enter the lungs. When the nose is blown, mucus is removed and any pathogens are trapped within it.
If you spend time in an environment with lots of pollution, when you blow your nose, the mucus will be black showing that the system works.
What are the trachea and bronchi defences?
The trachea runs from the nose towards the lungs. The cells that line the trachea also have hairs called cilia, which are much smaller than those in the nose. These are called ciliated cells. The ciliated cells waft their hairs and move mucus and pathogens upwards towards the throat where it is swallowed into your stomach. Other cells called goblet cells create the mucus in order to trap pathogens. The production of mucus in your airways is a physical barrier.
Cilliated cells reduce the amount of mucus and pathogens entering the lungs.
What is the stomach’s defences?
The stomach produces acid and this destroys the microorganisms in the mucus you swallow, as well as the majority of the pathogens you take in through your mouth in your food and drink.
What is the second line of defence and why is it needed?
The second line of defence is the immune system. Sometimes pathogens still get inside your body despite the body’s first line of defence mechanisms such as the skin and stomach.
The specific immune system acts to destroy any pathogens which pass through the non specific immune system to the body. A large part of the immune system is the white blood cells.
What are the different things white blood cells do to protect you from disease?
Engulf the pathogen(phagocytosis)
Producing antibodies
Producing antitoxins
What is phagocytosis?
Phagocytes( a type of white blood cells) ingest pathogens, digesting and destroying them so they cannot make you ill.
Why do lymphoctes produce antibodies?
Each pathogen has an antigen on their surface which is a structure which a specific complementary antibody can bind to. Once antibodies begin to bind to the pathogen, the pathogens start to clump together, resulting in it being easier for white blood cells to find them.
If you become infected again with the same pathogen, the specific complementary antibodies will be produced at a faster rate. The person will not feel the symptoms of the illness, they are said to be immune.
Why are antitoxins produced and what do they do?
Some pathogens produce toxins which make you feel ill. Lymphocytes can also produce antitoxins to neutralise these toxins.
What are antigens?
Antigens are protein substances found on the surface of cells.
What are antibodies?
Antibodies are proteins produced by a type of white blood called lymphocytes. Pathogens have proteins on their surface called antigens. When a pathogen infects the body, the lymphocytes recognise these antigens as foreign and attack them by producing antibodies.
Antibodies bind to specific antigens on pathogens. This means that only one type of antibody will bind to a matching antigen.
What do vaccinations do?
Vaccinations make an individual immune to a certain disease. This makes them protected against it before they have been infected.
What happens when a vaccinated person gets infected with that disease?
Their body will have already created the antibodies needed to fight the infection when they got vaccinated. So now the white blood cells can respond rapidly and make the antibodies quicker and can get rid of the pathogens before you even start to feel ill.
How do vaccinations make you immune to a disease? Explain the process of getting vaccinated
-Small amounts of dead or inactive pathogen and injected into your body.
-The antigens in the vaccine stimulate your white blood cells into making antibodies, the antibodies destroy the antigen without you getting ill.
You are then immune to future infections by the pathogen, that’s because your body can respond rapidly and make the correct antibody quicker, as if you already had the disease.
What are the advantages of vaccinations?
They have eradicated many disease so far e.g smallpox.
Epidemics and pandemics can be prevented through herd immunity.
What are disadvantages of vaccinations?
They are not always effective in providing immunity.
Bad reactions such as fevers can happen
What is herd immunity?
If a large proportion of the population is vaccinated and immune to a disease, the spread of the pathogen in the population is very much reduced and the disease may disappear.
How does herd immunity work?
Herd immunity limits the spread of the disease in the population making it harder for the pathogen to spread and when the majority are vaccinated it gives protection to people who are not vaccinated as well, because there is less chance of the non vaccinated person becoming ill as most people are vaccinated.
What do painkillers do?
Painkillers don’t help you kill the pathogens, they just relieve your symptoms which makes you feel better, but they don’t have any effect on curing you faster, you have to wait for your immune system to kill the pathogens.
What are antibiotics?
Antibiotics are medicines that kill bacterial pathogens inside the body, without damaging body cells.
Why don’t antibiotics work against viruses?
They cannot kill viruses, because viruses use body cells to reproduce, meaning any drugs that target them would target body cells too.
What different forms can antibiotics can be taken in?
Pill, syrup or directly into the bloodstream
Are there different types of antibiotics?
Some antibiotics kill a wide range of bacteria, others are very specific and only work against particular bacteria.
Why is it important you take the right type of antibiotic for a specific type of infection?
It is important that the right antibiotic is chosen and used. Specific bacteria should be treated with specific antibiotic so that it is the most effective against them.
Benefits of antibiotics?
They have prevented millions of deaths, bacterial diseases have killed millions of people in the past and now they can be cured with antibiotics, they have had an enormous effect on our society.
What is antibiotic resistance?
Antibiotic resistance is when antibiotics that used to kill a certain type of bacteria no longer work, because the bacteria is mutating to become resistant.
Why does antibiotic resistance happen?
Mutations can occur during reproduction resulting in certain bacteria no longer being killed by antibiotics. When these bacteria are exposed to antibiotics, only the non resistant ones die. The resistant bacteria survive and reproduce, meaning the population of resistant bacteria increases. This means that antibiotics that were previously effective no longer work.
