Understanding Ourselves

1. Understanding Ourselves (OCR) W Richards The Weald School

2. Body systems The RESPIRATORY SYSTEM: takes in _____ The ___________ SYSTEM: transports oxygen and glucose around the body The SKELETAL and MUSCULAR systems: use the _____ from glucose to allow ________ The DIGESTIVE SYSTEM: takes in ________ Words – energy, movement, oxygen, glucose, circulatory

3. 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… 3) The heart pumps the blood to the intestine (where oxygen and glucose are removed)… 5) After the oxygen and glucose have been removed for respiration the blood is sent back to the heart and starts again 4) … and to the rest of the body (where oxygen is removed)

4. 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. Blood pressure is measured in mmHg (millimetres of ______). Normal pressure is about 120/80 mmHg. Words – energy, mercury, blood, glucose, respiration, oxygen, cells

5. High Blood Pressure High blood pressure is a condition where the ______ and blood vessels experience extra strain. It can be caused by: • Excess weight • 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 ______. Words – alcohol, burst, smoking, heart, fat

6. (Aerobic) Respiration A while ago we learnt about ___ ______. Each of these life processes needs ENERGY. ___________ is the process our bodies use to produce this energy: Glucose + oxygen water + carbon dioxide + ENERGY C6H12O6 + 6O2 6H20 + 6CO2 + energy The glucose we need comes from ______ and the oxygen from _________. Water and carbon dioxide are breathed out. The MAIN product of this equation is _________. Words – breathing, energy, Mrs Gren, respiration, food

7. Anaerobic respiration Glucose lactic acid + a bit of energy Unlike aerobic respiration, anaerobic respiration is when energy is provided WITHOUT needing _________: This happens when the body can’t provide oxygen quick enough for __________ respiration to take place. Anaerobic respiration produces energy much _______ than aerobic respiration but only produces 1/20th as much. Lactic acid is also produced, and this can build up in muscles causing ______ and an oxygen ______. This “debt” then needs to be “repaid” by deep breathing to ________ the lactic acid. Words – debt, oxygen, fatigue, oxidise, aerobic, quicker

8. The Effect of Exercise Heart rate/min Breathing rate/min 100 225 Rest Exercise Recovery 75 175 50 125 25 75 5 mins 10 mins 15 mins 20 mins

9. Balanced diet A balanced diet should contain fats, proteins and carbohydrates in roughly these amounts: It should also contain water, vitamins, minerals and fibre.

10. Modern diets and health problems % obesity in the UK

11. Poor diets Lack of… Causes… If we don’t have a balanced diet we may suffer form a “deficiency symptom”:

12. 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

13. Body-Mass Index Mass (kg) Height2 (m2) BMI = A commonly-used way to indicate is someone is overweight or underweight is the Body Mass Index (BMI):

14. Protein Meat and fish are “first class” proteins Proteins are long chains of amino acids. There are two main types of these: • Essential amino acids (must be eaten) • Non-essential amino acids (can be made in the body) People who do not eat enough protein will not grow properly. Protein deficiency can result in a disease called kwasiorkor, where the muscles waste away and the belly swells. How much protein should we eat? RDA of protein (in g) = 0.75 x body mass (in kg)

15. Eating disorders Anorexia nervosa – this is a condition where sufferers restrict what they eat and sometimes starve themselves, leading to possible weight loss, abdominal pains, discoloured skin, irregular periods etc. Bulimia nervosa – this is when people vomit or take laxatives straight after eating to get the food out as quickly as possible. It can lead to weight fluctuations, poor skin, hair loss, irregular periods, tiredness etc.

16. The digestive system The whole point of digestion is to break down our food so that we can get the bits we need from it… The main foods affected are CARBOHYDRATES – these are broken down into GLUCOSE. Hydrochloric acid is produced in the stomach to kill bacteria. Digestion also depends on “enzymes”...

17. Enzymes Enzymes are chemicals produced by the body to help _______. When they react with food they break it down into ______ pieces which can then pass into the ______: Carbohydrase (produced in the mouth, pancreas and small intestine) breaks _______ (a carbohydrate) down into glucose: Protease (produced in the stomach, pancreas and small intestine) breaks _______ down into amino acids: Bloodstream Lipase (produced in the pancreas and small intestine) breaks fats (_____) down into fatty acids and glycerol: Words – blood, lipids, proteins, digestion, starch, smaller

18. Bile and the liver • Bile is a chemical produced in the liver and stored in the gall bladder. It has 2 functions: • It neutralises stomach acid and produces alkaline conditions for enzymes to work in • It emulsifies (“breaks down” fats: Fat globules Fat droplets

19. Disease A disease is any condition where the body does not work properly. It can be caused by a number of things: • A spread of infection from another person (an “infectious disease”, e.g. A cold) • Poor diets (e.g. Scurvy) • Organ malfunction (e.g. Diabetes) • Genetic inheritance (e.g. Colour blindness) • Mutations in cells (tumours, e.g. Cancer) – these can be caused by smoking, drinking, too much sun etc

20. Pathogens They can be breathed in through the mouth or nose They can enter through cuts or bites in the skin Pathogens are microbes (micro organisms) that can cause diseases. They can enter the body in a number of ways: …or other natural openings…

21. Disease 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: Bacteria Viruses • 1/1000th mm big • Living cells (some are harmless) • Grow very quickly • Affected by antibiotics • Examples: food poisoning, tetanus, sore throats • 1/1,000,000th mm big • Genetic info inside a protein coat • Not affected by antibiotics • Release poisons • Examples: colds, flu, polio, chicken pox

22. 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”.

23. Fungi Fungi can also cause unwanted conditions. These conditions can be treated with anti-fungal medicine and antibiotics. Some examples (don’t look if you’re faint hearted!):

24. Transmitting Diseases Pathogens can be transmitted in a number of ways: • “Horizontal transmission” (directly ______ an ill person) • “Vehicle transmission” (touching an ill person’s ________) • “Vertical transmission” (mother to ____) • Airborne (______ in the air) • Vector-borne (third party, e.g. __________) Words – mosquitoes, belongings, touching, baby, germs

25. Malaria

26. Microbes: our defence against them The breathing organs have hairs and produce mucus to cover the lining of these organs and trap the microbes Tears contain lysozyme, an enzyme that kills bacteria If our skin is cut platelets seal the wound by clotting The skin acts as a waterproof barrier Our blood contains white blood cells Our bodies have defence mechanisms against invading microbes:

27. Cleaning our air Our respiratory system has two types of specialised cell that help to keep our lungs clean: 1. Mucus is produced and traps dust, bacteria etc 2. The mucus is swept upwards to the mouth by cilia (cells with tiny hairs)

28. White blood cells 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: • They eat the microbe (these white blood cells are called “phagocytes”) • They produce antibodies to neutralise the microbe (“lymphocytes”) • The produce antitoxins to neutralise the poisons produced by microbes (lymphocytes again)

29. Producing antibodies You’re going down Step 1: The lymphocyte “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

30. Specific antibodies Antibodies are specific – they will neutralise the microbe they have been made for.

31. 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: • A vaccine with dead microbes is injected – the body is “tricked” into producing antibodies ready for the real thing. This is called ACTIVE IMMUNISATION • The antibodies are injected directly into the body – this is called PASSIVE IMMUNISATION.

32. Vaccinations For Against MMR vaccine 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:

33. Researching new medicines 1. Is it toxic? Tests are done on animals 2. Is it safe for humans? Human volunteers trial the drug Before new drugs can be approved they have to go through three stages: 3. Does it work? People with the illness are tested on. This can involve using a “placebo” – a dummy pill

34. The Nervous System The CENTRAL NERVOUS SYSTEM (CNS) enables us to react to our surroundings. It consists mainly of the brain, the spinal chord, nerve cells (“neurones”) and receptors. • Types of receptor: • Light receptors in the eyes • Sound receptors in the ears • Taste receptors on the tongue • Smell receptors in the nose • Touch, pressure and temperature receptors in the skin • Changes of position receptors in the ears (balance)

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

36. Examples of reactions

37. Types of nerve cell Nucleus Muscle strands (effector) Cell body Dendrites Impulse Impulse Nerve cells (neurones) are elongated with branched endings to connect to many muscles fibres. 1) Motor neurone 2) Sensory neurone 3) Relay neurone

38. Synapses 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

39. Conscious actions 4) The brain decides to move away the hand 3) Here another sensory neurone carries the signal to the brain 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 1) Receptors in your skin detect a stimulus 6) Which then moves the hand away Stimulus Receptor Sensory Neurone Coordinator Motor Neurone Effector Response A conscious action is one where the brain makes a considered response. Here’s what happens:

40. 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…

41. Reflex actions 3. Relay neurone in the spinal chord 2. Sensory neurone 4. Motor neurone 1. Receptor 5. Effector

42. Vision “Binocular vision” “Monocular vision”

43. The Eye Iris Sclera Lens Retina Pupil Optic nerve Optic nerve Cornea Suspensory ligaments Suspensory ligaments Ciliary muscles

44. Seeing things Rays of light are refracted (bent) first by the cornea and then by the lens. They focus on the retina.

45. Focussing on different distances For distant objects the ciliary muscles relax and the suspensory ligaments pull tight making the lens pull thin – the light doesn’t bend as much. For close objects the ciliary muscles contract allowing the lens to go fat, thus bending the light more.

46. The Iris Reflex When the light is bright the radial muscles relax, the circular muscles contract and the pupil increases in size. When the light is bright the radial muscles _____, the circular muscles _______ and the pupil ________ in size.

47. Drugs Research Project Explain and give examples for the following: • Why do people use legal drugs? • What are the drawbacks of legal drugs? • Alchohol is a legal drug. What does it do to the human body? • Why do people use illegal drugs? • What are the drawbacks of illegal drugs? What can they cause? • Find out which drugs are in which classes

48. Drugs Speed up synapse transmissions Reactions could become faster Highly strung, leads to exhaustion Slow down synapse transmissions May make you drowsy, you shouldn’t drive Highly addictive, make you irritable Prevent synapse transmissions May make you drowsy, you shouldn’t drive Side effects include dizziness or itchiness

49. Smoking • Cigarettes contain 3 harmful things: • NICOTINE, which is an ___________ drug that raises the heart beat, narrows the arteries and so causes ____ _____ _____. This leads to heart _________. • TAR, which coats the lining of the _______ making them less able to take in oxygen. It also contains carcinogens which cause ______________. • 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

50. Homeostasis Homeostasis means “controlling internal conditions”: 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