Presentation on theme: "12/01/2014 B2 – Keeping Healthy W Richards The Weald School (OCR 21 st Century)"— Presentation transcript:
12/01/2014 B2 – Keeping Healthy W Richards The Weald School (OCR 21 st Century)
B2.1 How do our bodies resist infection?
12/01/2014Microbes Microbes are micro organisms that can cause diseases. They can enter the body in a number of ways: …or other natural openings… They can be breathed in through the mouth or nose They can enter through cuts or bites in the skin Microbes (or the poisons they produce) damage cells – these are the symptoms of a disease.
12/01/2014Disease A disease is any condition where the body isn t working as it should. This could be caused by a malfunction in the body (as with diabetes) or it could be caused by a type of PATHOGEN (a microbe that causes disease): VirusesBacteria 1/1000 th mm big Living cells (some are harmless) Grow very quickly Affected by antibiotics Examples: food poisoning, tetanus, sore throats 1/1,000,000 th mm big Genetic info inside a protein coat Not affected by antibiotics Release poisons Examples: colds, flu, polio, chicken pox
Bacteria Growth Bacteria can grow and multiply at very quick rates, especially inside the human body. Imagine bacteria could double every 15 minutes. Draw a graph of how many you would have at the following times: TimeNo. of bacteria 0 min 30 mins 1 hr 1:30 2:00 2:30 3:00 3:30 4:00 4:30 5: No of bacteria Time
12/01/2014 Producing antibodies Step 1: The white blood cell sees the pathogen (microbe) Step 2: The cell produces antibodies to fit the pathogen Step 3: The antibodies fit onto the pathogens and cause them to clump Step 4: The pathogens are eaten by the white blood cells You re going down
12/01/2014 Specific antibodies Antibodies are specific – they will neutralise the microbe they have been made for. They do this by recognising the antigen on the surface of the microbe. Microbe Antigen Once the body has made the antibody memory cells can make it again very quickly if needed, which protects you from catching the disease again.
B2.2 What are vaccine and antibiotics?
12/01/2014Vaccinations Vaccinations work by injecting a _____ or weakened form of a ________ into the body. The body is then tricked into producing _______. The memory cells then remember the antigen so that, if the person catches the real disease, they are ready for it. In order to prevent an ______, sometimes large numbers of the population can be ______. A possible problem with this is that people can feel ____ ______. Words – antibodies, vaccinated, side effects, epidemic, dead, microbe
Using Antimicrobials 1) Antibacterials kill bacteria but overuse of them can lead to bacteria becoming resistant (e.g. the MRSA superbug). This means that antibiotics must be used sparingly. They also have no effect on virii. 2) Antifungals can be used to treat fungal infections like Athletes foot. Fungi can also become immune over time. Antimicrobials are chemicals used to kill or inhibit microbes. For example:
Fungi Fungi can also cause unwanted conditions. These conditions can be treated with anti-fungal medicine and antibiotics. Some examples (dont look if youre faint hearted!):
12/01/2014 How bacteria become immune Although vaccinations and antibiotics are useful in the fight against pathogens, bacteria and virii can mutate to form a new, resistant strain: 1)Mutation – some strains of bacteria can genetically mutate to develop _______ to the antibiotics. 2)The non-resistant bacteria are _____ by the _______. 3)The resistant bacteria _______ and pass on their mutations to their ______. Don t use antibiotics unless you need to!! Bacteria Penicillin No effect!! Words – offspring, resistance, killed, antibiotics, reproduce
The rise of MRSA No. of MRSA cases Year
12/01/2014 Researching new medicines Before new drugs can be approved they have to go through three stages. What are the advantages and disadvantages of each stage? 3. Is it safe for humans? Human volunteers are tested on, both with and without the disease. 1. Is it toxic? Tests are done on cells 2. Is it safe for animals? Animal tests are carried out
12/01/2014Placebos Clinical trials can be done by open label (i.e. everyone knows whats being given to who) or in different ways: 1) Blind trials Patients do not know which drugs they are taking – a real drug or a placebo 2) Double blind trial Neither the doctors or the patients know if they are taking the real drug Placebos offer an ethical dilemma as a patient might be sick and still be given a dummy pill. Also, you might notice if you had a placebo as you wouldnt get the side effects of normal drugs...
12/01/2014 An example of drug development - Thalidomide Mat Fraser, comedian and actor Tony Melendez, guitarist
12/01/2014 Developing new drugs Before a new drug can be approved it has to go through a strict testing process. Consider the example of thalidomide: DateEvent Mid 1950s Late 1950s Early 1960s Mid 1960s Animal testing using thalidomide was undertaken. Tests showed that it was safe but the tests wereinadequate – no tests were done on pregnant animals Thalidomide prescribed to pregnant mothers to help sleep and morning sickness problems Babies are born with birth defects and the drug was banned worldwide. Around 12,000 deformed Thalidomide babies born, 4,000 die in first year. Tests show that Thalidomide can help leprosy sufferers and it is still used today for this purpose.
B2.3 What factors affect Heart Disease?
Double Circulation 1) Blood gets pumped from the heart to the lungs and picks up oxygen 2) The blood is then taken back to the heart which needs its own blood supply… 3) The heart pumps the blood to the intestine (where oxygen and glucose are removed)… 4) … and to the rest of the body (where oxygen is removed) 5) After the oxygen and glucose have been removed for respiration the blood is sent back to the heart and starts again
The Circulatory system The circulatory system is responsible for pumping ______ around the body. We need blood to be taken around the body because blood contains ________ and _______. These are needed so that all the ____ in our bodies can produce _____ through _________. Blood is pumped at high pressure and measuring the pulse rate can tell us the heart rate. Words – energy, blood, glucose, respiration, oxygen, cells
Arteries, veins and capillaries Arteries carry high pressure blood away from the heart. They have smaller lumen and no valves. Veins carry low pressure blood back to the heart. They have thinner, less elastic walls and have valves to prevent backflow of blood. Capillaries have thin walls (one cell thick) to allow glucose and oxygen to pass through. Also used to connect arteries to veins. Lumen
Measuring Blood Pressure Blood pressure measurements are taken in terms of Pressure when heart is contracting over pressure when heart is relaxed. Healthy blood pressures are defined as being within a range, due to the fact that every person is different.
Heart disease Cholesterol
High Blood Pressure High blood pressure is a condition where the ______ and blood vessels experience extra strain. It can be caused by: Excess weight or lack of exercise High stress levels _____ Excess _______ Diets that are high in saturated ___, sugar or salt Long term high blood pressure can cause blood vessels to weaken or even ______ and can lead to heart disease. Words – alcohol, burst, smoking, heart, fat
Heart Disease and Lifestyle Who is the most likely to die of heart disease in the next 20 years?
Heart Disease Risks Clearly, the risk of heart disease depends on a number of factors: 1)Lack of _________ 2)Eating foods high in _________ fats 3)______ factors, e.g. if your parents had it 4)Whether or not you _______ Words – smoking, exercise, genetic, saturated Factors that affect the risk of heart disease can be identified via large-scale genetic studies.
12/01/2014Drugs Why do people use illegal drugs?
12/01/2014 Cannabis: Pros and cons In January 2004 cannabis was changed from a class B drug to a class C drug. Some people think that Cannabis should be made legal. What are the pros and cons of cannabis? Pros: Cons:
12/01/2014 Drugs Research Project Explain and give examples for the following: 1)Why do people use illegal drugs? 2)What are the drawbacks of illegal drugs? What can they cause? 3)Choose one drug and discuss how it affects the human body
B2.4 Keeping a Healthy Water Balance
Homeostasis Homeostasis means controlling internal conditions and it is achieved using the bodys nervous and hormonal systems. Some examples of things that need to stay constant: Body temperature Amount of sugar in the body Amount of water in the body The body does all these things so that its cells can continue to work normally. Lets look at temperature and water content in more detail…
Homeostasis in different conditions
Body Temperature Effectors (muscles and sweat glands) carry out the response Receptors in the skin detect the external temperature Temperature detectors in the brain detect the blood temperature The brain coordinates a response using hormones Receptor – Processing Centre - Effector
Controlling Water Content Low blood water level causes a high salt concentration Receptors in the hypothalamus detect the high salt content More ADH is secreted into the blood by the pituitary gland The kidney becomes more permeable to water so more is absorbed. The bladder fills with a small quantity of urine Normal blood water level is achieved. Negative Feedback
Controlling Water Content 2 High blood water level causes a low salt concentration Receptors in the hypothalamus detect the low salt content Less ADH is secreted into the blood by the pituitary gland The kidney becomes less permeable to water so more is absorbed. The bladder fills with a large quantity of urine Normal blood water level is achieved. Negative Feedback
Controlling Water Levels Factors affecting water content of our bodies: External temperature – e.g. is the person _______? Intake of _______ and food How much is lost through breathing and _______ Alcohol – this can suppress ADH which leads to __________ due to the body producing more urine Drugs, e.g. Ecstasy, which causes increased ____ production. Our bodies control water content using a ____ ______ mechanism. Controlling water content is important as many process that occur in _____ need the correct water content in each cell. Words – ADH, negative feedback, water, sweating, dehydration, cells, urine