1. 01/03/2016Biology New Bridge Academy Science dept. (AQA)

2. 01/03/2016 The Nervous System The NERVOUS SYSTEM enables us to react to our surroundings. It consists mainly of the brain, the spinal chord, nerve cells (“neurones”) and receptors. Types of receptor: 1)Light receptors in the eyes 2)Sound receptors in the ears 3)Taste receptors on the tongue 4)Smell receptors in the nose 5)Touch, pressure and temperature receptors in the skin 6)Changes of position receptors in the ears (balance)

3. 01/03/2016 Nervous Reactions When we react to a stimulus our bodies use the following pattern: Stimulus Receptor Coordinator Effector Response For example, consider a man and a camel: Oh No! What are the stimulus, receptor, coordinator, effector and response in this situation?

4. 01/03/2016 Examples of reactions StimulusReceptor (i.e. the thing that detects the stimulus) Effector (i.e. the thing that will do the reaction) Response (i.e. action taken) Bright light Sour taste Losing balance Sit on a drawing pin

5. 01/03/2016 Types of nerve cell NucleusMuscle strands (effector) Cell body 1) Motor neurone2) Sensory neurone3) Relay neurone Impulse Nerve cells (neurones) are elongated with branched endings to connect to many muscles fibres.

6. 01/03/2016 Conscious actions A conscious action is one where the brain makes a considered response. Here’s what happens: Stimulus Receptor Sensory Neurone Coordinator Motor Neurone Effector Response 1) Receptors in your skin detect a stimulus 3) Here another sensory neurone carries the signal to the brain 4) The brain decides to move away the hand 5) This impulse is sent by MOTOR NEURONES to the hand muscles (the effectors) via the spinal chord… 2) The impulse is carried by SENSORY NEURONES to the spinal chord 6) Which then moves the hand away

7. 01/03/2016 Reflex actions Sometimes conscious action is too slow to prevent harm, e.g… In situations like this the body bypasses the brain to produce a quicker response. Here’s how it works…

8. 01/03/2016 Reflex actions 1. Receptor2. Sensory neurone 3. Relay neurone in the spinal chord 4. Motor neurone 5. Effector

9. 01/03/2016Synapses Neurones never ____ each other – there is a small gap between them called a _____. A signal is sent from one _______ to the next by a _______ transmitter across the synapse. These transmitters are then ________. Words – chemical, synapse, neurone, touch, destroyed

10. 01/03/2016Homeostasis Homeostasis means “controlling internal conditions”: Waste products that need to be removed + how CO 2 Urea Internal conditions that need controlling + how Temperature Ion content Water content Blood glucose Produced by respiration, removed via lungs Produced by liver breaking down amino acids, removed by kidneys and transferred to bladder Increased by shivering, lost by sweating Increased by eating, lost by sweating + urine Increased by drinking, lost by sweating + urine Increased and decreased by hormones

11. 01/03/2016Fertility In normal circumstances natural hormones are responsible for releasing the egg and for thickening the lining of the womb. These hormones are produced by the pituitary gland in the brain and in the ovaries. 1)…stimulate the release of eggs 2)…inhibit the release of eggs The amount of glucose in our blood is an example of a process controlled by hormones. Hormones are “chemical messengers”, produced by glands and tranposrted by blood. Another example of a process controlled by hormones is the menstrual cycle, where hormones can...

12. 01/03/2016Fertility 3 hormones are involved in the menstrual cycle: oestrogen, LH and FSH. Here’s how: Step 3: LH stimulates the release of the mature egg in the middle of the menstrual cycle Artificial fertility: 1)To INCREASE fertility FSH is given to stimulate maturation of eggs. 2)To DECREASE fertility oestrogen is given (“The Pill”) to inhibit FSH production stopping eggs from maturing. Step 1: FSH produced by the pituitary gland causes both an egg to mature and the ovaries to start producing oestrogen Step 2: The rising levels of oestrogen cause the pituitary gland to stop producing FSH and produce LH instead

13. 01/03/2016 Balanced diet A balanced diet should contain fats, proteins and carbohydrates in roughly these amounts: It should also contain water, vitamins, minerals and fibre.

14. 01/03/2016 Poor diets If we don’t have a balanced diet we may suffer form a “deficiency symptom”: Vitamin D Protein Vitamin C Vitamin A Iron Calcium Anaemia Scurvy (bleeding gums and joints) Weak bones and teeth Wasting of body tissue Rickets Poor night vision Lack of…Causes…

15. 01/03/2016 Metabolic Rate and health The rate at which our bodies carry out chemical reactions is called the “metabolic rate”. This rate varies with: The amount of work we do The amount of fat in our body Inherited factors ConditionHow this affects our health Lack of exercise Fatty diets Warm weather Using cars instead of walking Playing XBox instead of football

16. 01/03/2016 Conditions caused by increased weight Obesity is a condition caused by excess weight. This can also lead to the following diseases: Athiritis What is it? What causes it? Heart disease What is it? What causes it? High blood pressure What is it? What causes it? Diabetes What is it? What causes it?

17. 01/03/2016 Heart disease

18. 01/03/2016Cholesterol Cholesterol is a fatty substance made in the liver from saturated fats in your food. The amount of it in your blood depends on your diet and inherited factors. Cholesterol is transported in the bloodstream attached to proteins. This combination is called a “lipoprotein”: Low density lipoproteins (LDL) High density lipoproteins (HDL) “Bad” lipoproteins Carry cholesterol to cells High levels of LDLs cause fat to build up in the artery “Good” lipoproteins Carry cholesterol back to liver Helps prevent cholesterol building up

19. 01/03/2016 Restoring the balance Saturated fats (“bad fats”) increase cholesterol levels. Mono-unsaturated fats and polyunsaturates may help reduce cholesterol and restore the balance between LDLs and HDLs.

20. 01/03/2016 Modern diets and health problems % obesity in the UK

21. 01/03/2016Drugs Why do people use illegal drugs?

22. 01/03/2016 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:

23. 01/03/2016Smoking Cigarettes contain 3 harmful things: 1.NICOTINE, which is an ___________ drug that raises the heart beat, narrows the arteries and so causes ____ _____ _____. This leads to heart _________. 2.TAR, which coats the lining of the _______ making them less able to take in oxygen. It also contains carcinogens which cause ______________. 3.CARBON MONOXIDE, which is a _______ ____ which joins up with ____ blood cells making them incapable of transporting _____________ around the body. In pregnant women it can cause oxygen deprivation, leading to low birth ______. Words – high blood pressure, oxygen, red, addictive, disease, poisonous gas, lungs, cancer, mass

24. 01/03/2016 Tobacco and Lung Cancer Sir Richard Doll, 1912-2005 Over 50 years I proved the link between smoking and lung cancer. I published my first findings in 1950, based on patients in London hospitals, and then studied 40,000 doctors and proved a link in a paper published in 1954. Smoking has existed in Western culture since the 16th Century. However, scientists only proved the link between it and various diseases shortly after the Second World War.

25. 01/03/2016 Stopping smoking There are generally two methods of stopping smoking: “Cold turkey” – stopping completely with no help Nicotine Replacement Therapy – e.g. Patches, gum etc What are the advantages and disadvantages of each?

26. 01/03/2016 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 were “inadequate” – 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.

27. 01/03/2016 Thalidomide children Mat Fraser, comedian and actor Tony Melendez, guitarist

28. 01/03/2016 Drugs Research Project Explain and give examples for the following: 1)Why do people use legal drugs? 2)What are the drawbacks of legal drugs? 3)Alchohol is a legal drug. What does it do to the human body? 4)Why do people use illegal drugs? 5)What are the drawbacks of illegal drugs? What can they cause? 6)Choose one drug and discuss how it affects the human body

29. 01/03/2016Microbes 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

30. 01/03/2016Disease 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

31. 01/03/2016 Microbes: our defence against them Our bodies have four major defence mechanisms against invading microbes: If our skin is cut platelets seal the wound by clotting The breathing organs produce mucus to cover the lining of these organs and trap the microbes The skin acts as a barrier Our blood contains white blood cells

32. 01/03/2016 Fighting disease If microbes enter our body they need to be neutralised or killed. This is done by WHITE BLOOD CELLS: White blood cells do 3 things: 1)They eat the microbe 2)They produce antibodies to neutralise the microbe 3)The produce antitoxins to neutralise the poisons produced by microbes

33. 01/03/2016 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

34. 01/03/2016 Fighting disease NATURAL IMMUNITY This is when antibodies are produced by a person when needed or they are passed on by the mother during pregnancy. ARTIFICIAL IMMUNITY Can be done in two ways: 1)A vaccine with dead microbes is injected – the body is “tricked” into producing antibodies ready for the real thing. This is called PASSIVE IMMUNISATION 2)The antibodies are injected directly into the body – this is called ACTIVE IMMUNISATION.

35. 01/03/2016 Using Antibiotics Antibiotics can be used to kill bacteria. However, there are two problems: 1) Overuse of antibiotics can lead to bacteria becoming resistant (e.g. the MRSA “superbug”). This means that antibiotics must be used sparingly. 2) Antibiotics have no effect on a virus, like the common cold. It is difficult to kill a virus without damaging body tissue. A virus is usually allowed to “run its course”.

36. 01/03/2016 A smaller example… Although vaccinations and antibiotics are useful in the fight against pathogens, bacteria and virii can mutate to form a new, resistant “strain”: 1)Variation – some strains of bacteria are resistant and some aren’t. 2)Competition – The non-resistant bacteria are killed by the penicillin. 3)Survival of the fittest – the resistant bacteria survive. 4)Passing on of genes – the resistant bacteria reproduce and pass on their adaptations to their offspring. This is how the bird flu virus developed. Bacteria Penicillin

37. 01/03/2016 Using Painkillers Painkillers are drugs used to relieve the symptoms of disease but without killin the pathogens, for example: Paracetamol Aspirin Ibuprofen

38. 01/03/2016 The spread of infection Ignaz Semmelweiss 1818-1865 Guten tag. In the mid-19th century I realised that many deaths in hospitals could be avoided by insisting on clean hands and equipment. As a result of my work deaths in my wards fell from 12% to 1%. More people die due to infections from hospitals than on the roads in Britain. Hospitals have been trying to improve hygiene standards: YearAmount of hand wash solution used (litres per 1000 patient days) MRSA infections per 100 patients 19933.50.50 19956.90.48 199710.90.25

39. 01/03/2016Vaccinations Some people argue that the MMR vaccine is a good idea, others think it is a bad idea. Briefly summarise each side of the argument: MMR vaccine ForAgainst