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Arteries carry blood away from the heart to the body. Low BP… - Tissues don’t get all of the oxygen and food needed. - Faint, dizzy, poor circulation Systolic – contract – large number. Average – 135/85mmHg Diastolic – relax – small number. Measured by… strength, speed, agility, flexibility and stamina. Stamina – cardiovascular efficiency – how well the heart supplies the muscles with blood. Veins carry blood back to the heart. Pressure decreases as it moves through the system. Fit – How well you can perform physical tasks. To reach the whole body. Healthy – Being free from illness and disease. High BP… Pumped under pressure by the - Stress, smoking, poor diet, heart. overweight. Health and Blood - Blood vessels burst, Blood Pressure Fitness strokes, kidney damage, B1 – Understanding Ourselves brain damage Smoking Increases blood pressure… Carbon monoxide… combines with haemoglobin in RBC and reduces the amount of oxygen carried. Heart beats faster to make up for this. Nicotine… stimulant which increases the heart rate Heart Disease A disease that effects the heart. Risks… diets high in fat and salt. • • • Saturated fats cause excess cholesterol to build up in the arteries. You need some cholesterol to make cell membranes. This causes plaques which narrow arteries. This restricts the flow of blood which can lead to a heart attack. Salt… Too much causes high blood pressure. This can damage arteries. This can cause plaques to build up, block the artery, restrict blood flow and lead to a heart attack. Thrombosis… this is a blood clot. If it blocks an artery, particularly in the heart, the heart muscles loses blood supply. This causes a heart attack. Nutrient Used for Made of Extras Carbohydrate Energy Simple sugars, e.g. - glucose Stored in the liver as glycogen or converted to fats. Fats Energy and insulation Fatty acids and glycerol Stored under the skin and around organs as adipose tissue. Proteins Growth and repair. Energy in emergencies Amino acids Don’t get stored. Proteins from meat and fish are first class proteins – contain amino acids the body cant make. Plant proteins are second class and don’t contain all essential amino acids. Vitamins and minerals Keep the body healthy, e.g. – vit C to prevent scurvy, iron to help make haemoglobin Chemical compounds Fibre Makes you poo – keeps a healthy digestive system Indigestible food stuffs Water Hydration Hydrogen and oxygen Supplies essential nutrients. Balanced Diet Children and teens need more protein as they are growing. Older people need more calcium to protect against bone diseases. Girls need more iron due to menstruation. Active people need more protein for their muscles and carbs for energy.. B1 – Understanding Ourselves Protein… • Too little protein causes kwashiorkor. • This happens in developing countries due to overpopulation, lack of money, poor agriculture, war etc. • EAR – Estimated daily requirement • EAR = 0.6 x body mass (kg) • EAR varies with age and whether your pregnant or not. BMI (Body Mass Index) BMI Helps to show if people under 18.5 are overweight or between 18.5 and underweight. Not always 24.9 reliable. Athletes have a between 25 and lot of muscles which 29.9 weighs more than fats so between 30 and they have a high BMI 39.9 even though they are over 40 healthy. BMI = Body mass (kg) ----------(Height)2 Why do people have different diets? Personal – vegetarians, vegans. meaning underweight normal overweight obese very obese Religion – Hindus don’t eat beef as they think cows are sacred. Medical – Some people have allergies and intolerances. Malaria… • Caused by protozoan (parasite) • Protozoan lives off other organisms, these are the host • Carried by mosquitos – vector • Reduce malaria by draining stagnant water or spraying it with insecticide, put fish in the water to eat the larvae, people protect themselves by using mosquito nets and repellents. Healthy lifestyle and diet can help reduce chance of Pathogen Disease cancer, e.g. – don’t smoke, bacteria cholera more fibre and less viruses influenza (flu) sun/sunbeds.. fungi athlete’s foot protozoa malaria Benign – Not normally dangerous, cells don’t spread, slow dividing. Malignant – Rapid division and growth, cells spread, dangerous. When cells divide out of control. Caused by pathogens Non-Infectious Diseases: Not caused by pathogens and so are not infectious. For example: • scurvy is caused by vitamin C deficiency • anaemia is caused by iron deficiency • diabetes and cancer are disorders of the body. Some disorders are inherited, such as red-green colour vision deficiency. Plus, when you cut yourself, blood clots to form a scab to prevent pathogens entering the body Infectious Disease Cancer B1 – Understanding Ourselves Immunisation – Helps prevent infections White Blood Cells – Help destroy pathogens that have entered the body and are dividing rapidly. They have 3 attacks… • Engulfing the pathogen and digesting it • Producing antitoxins that the pathogen produces • Producing antibodies… WBC sees the pathogen and produces specifically shaped antibodies to fit it. The antibodies fit the pathogens, cause them to clump and the WBC digests them. Active Immunity – Immune system makes its own antibodies either by being ill or by immunisation. Passive Immunity – You use antibodies made by another organism, e.g. – breast milk. Advantages of Immunisation – protection, stops the spread. Disadvantages of Immunisation – short term side effects, e.g. – swelling, cant have them if you are ill, people think it can cause other disorders such as autism. Antibiotic resistance: Over time, bacteria can become resistant to certain antibiotics. MRSA is methicillin-resistant Staphylococcus aureus. It is very dangerous because it is resistant to most antibiotics. To slow down or stop the development of other strains of resistant bacteria, we should: • avoid the unnecessary use of antibiotics • always complete the full course. Drug testing: • Drugs are substances that cause changes to the body. • Antibiotics are drugs that kill bacteria, but not viruses. • Antivirals are drugs that prevent viruses reproducing. New medical drugs have to be tested to ensure that they work, and are safe, before they can be prescribed. There are three main stages of testing… • The drugs are tested using computer models and human cells grown in a laboratory. Many substances fail this test because they damage cells or do not seem to work. • Drugs that pass the first stage are tested on animals. In the UK, new medicines have to undergo these tests. But it is illegal to test cosmetics and tobacco products on animals. A typical test involves giving a known amount of a substance to the animals, then monitoring them carefully for any side-effects. • Drugs that have passed animal tests are used in clinical trials. They are tested on healthy volunteers to check that they are safe. Very low doses of the drug are given to begin with. If there are no problems, further clinical trials are done to find the optimum dose for the drug. Clinical trials are not without risk. Sometimes severe and unexpected side-effects occur. Most substances do not pass all of the tests and trials, so drug development is expensive and takes a long time. Double blind trials: It is important to be certain that a drug really does have positive effects, rather than people feeling better simply because they expect to feel better if they take a medicine. This is called the ‘placebo effect’. Double blind trials aim to minimise the placebo effect. Some patients are given the drug while others are given a placebo. A placebo is designed to appear exactly the same as the drug itself, but it does not actually contain any of the drug. The doctors and patients are not told who have received the drug and who have received the placebo until the trial is over. Drugs B1 – Understanding Ourselves Alter the way the body works… • Recreational – take a drug for fun for a high • Medicinal – Prescribed/bought to help the body/illness Addicted – You need a drug Tolerance – Your body is used to it so you need a higher dose for the same high Withdrawal – The symptoms you experience when coming off a drug addiction Rehabilitation – The help and support to get over a drug addiction Stimulants and depressants affect the synapses between neurones in the nervous system: • stimulants cause more neurotransmitter molecules to diffuse across the synapse • depressants stop the next neurone sending nerve impulses – they bind to the receptor molecules it needs to respond to the neurotransmitter molecules. type of drug effect on the body example depressant slows down brain activity hallucinogen alters what we see and hear LSD painkiller blocks nerve impulses performance enhancer improves muscle development anabolic steroids stimulant increases brain activity Class A • • • Max 7 years in prison and fine for possession Life in prison for supplying E.g. heroin, methadone, cocaine ecstasy, LSD, magic mushrooms Class B • • • Max 5 years in prison and a fine for possession 14 years in prison for supplying E.g. – amphetamines barbiturates, cannabis alcohol, solvents, temazepam aspirin, paracetamol nicotine, caffeine, ecstasy Class C • • • Max 2 years in prison and a fine for possession 14 years in prison for supplying E.g. – anabolic steroids, valium, tamazepam Collects in the lungs and is full of toxic chemicals called carcinogens. This can cause cancerous tumours to develop leading to lung caner Smoking causes low blood oxygen in the mother and lack of oxygen to the developing baby. Low birth weight babies Reduces the ability of RBC to carry oxygen. Can lead to heart disease and if the heart has a lack of oxygen this can cause a heart attack Tar Cilia in the trachea, bronchi and bronchioles become damaged. Excess mucus cant be shifted so it sticks to the air passages giving a terrible cough. Smokers Cough Carbon Monoxide Makes cigarettes addictive and speeds up the heart rate Nicotine Smoking Emphysema B1 – Understanding Ourselves The lungs become damaged, particularly the alveoli. They lose the elasticity and not as much oxygen can pass into the RBCs. Alcohol Depressant – slows down your nervous system. Makes you feel less inhibited which can be positive for socialising. Can also cause negative effects… • Impaired judgement • Poor balance • Poor coordination • Slurred speech • Blurred vision • sleepiness You should not drive, fly a plane or operate heavy machinery when drunk. Is a poison so it is therefor broken down by enzymes in the liver. Doctors recommend no more than… • 21 units per week for a man • 14 units per week for a woman Some of the products of alcohol are toxic so if you drink too much over a long period you can damage your liver cells – cirrhosis. The liver becomes scarred and therefore cant clean the blood properly. Dangerous substances build up in the blood and can cause serious problems for the body. The effector carries out the appropriate response. The effector (normally a muscle or gland) receives the message. CNS decides what to do and sends a message along the motor neurone. Message sent to CNS (central nervous system (brain and spinal cord)). Message sent along the sensory neurone. Organ Receptor Eye Light Ear Hearing and balance Tongue Chemical Nose Chemical Skin Heat, temperature and pressure Normally found in sense organs Detect stimuli in your environment Receptors B1 – Understanding Ourselves Reflex actions – conscious brain not involved Electrical insulator to help the impulse pass To connect with other neurones Signal passes down here They are very long to speed up the impulse. Neurones are nerve cells. They carry information as tiny electrical signals. There are three different types of neurones, each with a slightly different function: • sensory neurones carry signals from receptors to the spinal cord and brain • relay neurones carry messages from one part of the CNS to another • motor neurones carry signals from the CNS to effectors • • • • • Neurones don’t touch and the gap is a synapse The impulse causes a neurotransmitter to be released and diffuse across the gap This bind to the receptor molecules This causes a new signal to be generated in the next neurone The signal carries on part Cornea description function Front part of the tough outer coat, the sclera. It refracts light - bends it as it is convex and transparent. enters the eye Iris Pigmented - decides the colour of your eyes - so light cannot pass through. Its muscles contract controls how much light enters and relax to alter the size of its central hole or the pupil pupil. Lens Transparent, bi-convex, flexible disc behind the iris attached by the suspensory ligaments to the focuses light onto the retina ciliary muscles. Retina The lining of the back of eye containing two types of photoreceptor cells - rods - sensitive to dim light and black and white, cones - sensitive to contains the light receptors colour. A small area called the fovea in the middle of the retina has many more cones than rods. Optic nerve Bundle of sensory neurones at back of eye. B1 – Understanding Ourselves Light passes through the eyeball to the retina. It is refracted (its rays are bent) by the cornea and lens, so that the light is brought to a focus on the retina. To look at close objects… • Ciliary muscle contracts • Suspensory ligament slackens • Lens is more rounded so light is refracted more To look at distant objects… • Ciliary muscle relaxes • Suspensory ligament pull tight • Lens is more narrow and thin so less light refracted Binocular vision Because our eyes sit side by side, each eye captures a slightly different view. This is called binocular vision. When signals from the two eyes reach the brain, they are superimposed and processed into a single picture with depth. As a result, we get a 3D picture and are able to judge distances well. Most birds and lizards have monocular vision - their eyes are on each side of their head. This gives them a greater field of view, which is useful for spotting predators. However, they have poor depth perception. carries impulses from the eye to the brain Red/green colour blindness – Lack of receptors in retina – cant distinguish between red and green. Short-sight Someone with short-sight can see near objects clearly, but can't focus properly on distant objects. This is caused by the eyeball being elongated, so that the distance between the lens and the retina is too great. It can be corrected by placing a concave lens in front of the eye. Long-sight Someone with long-sight can see distant objects clearly, but can't focus properly on near objects. This is because the lens focuses the sharpest image behind the retina, instead of on it. This defect is often agerelated, and due to a loss of elasticity in the lens. It is corrected by putting a convex lens in front of the eye. Negative feedback is a mechanism the body uses to keep all these things automatically steady We need to maintain things such as CO2, water and body temperature. Keeping conditions in the body stable so you can function Controlled by thermoregulatory centre in the brain. Receptors in the skin provide information. Needs to be kept at 37oC so our enzymes work properly. Temperature Control Maintaining a constant internal environment Controlling blood sugar glucose level effect on pancreas too high insulin secreted into the blood liver converts glucose into glycogen insulin not secreted into the blood liver does not convert glucose into glycogen too low effect on liver Homeostasis Hyperthermia – exposed to high temperatures causing dehydration and heat stroke. Can kill. Hypothermia – exposed to low temperatures. Can Kill. B1 – Understanding Ourselves effect on glucose level goes down Insulin, a hormone secreted by the pancreas, controls blood sugar levels in the body. It travels from the pancreas to the liver in the bloodstream. As with other responses controlled by hormones, the response is slower but longer lasting than if it had been controlled by the nervous system. Type 1 diabetes goes up Who it mainly affects Type 2 diabetes Adults, normally over the age of 40 (there Children and is a greater risk in teenagers. Adults those who have poor under the age of 40. diets and/or are overweight). How it works The body no longer The pancreas stops responds to its insulin. making enough insulin. How it is controlled Injections of insulin for life and an appropriate diet. Exercise and The amount of insulin appropriate diet. needed depends on diet and activity In a shoot, the shaded side contains more auxin. This means that the shaded side grows longer, causing the shoot to bend towards the light. The diagram shows the typical results seen when growing oat seedlings in a box, with a light at one side. Results and explanation Seedlings The tips have been removed. No auxin is produced and the shoots do not grow longer. A The tips have been covered so light cannot reach them. Auxin is in the same concentration on both sides of the shoots, so they grow longer evenly on both sides. B Shoots and roots respond differently to high concentrations of auxins: • cells in shoots grow more • cells in roots grow less. Auxins can move through a plant dissolved in water. part of plant shoot root Use of Plant Hormones One side of the tips are in more light than the other side. Auxin is in a greater concentration on the shaded side, causing the cells there to grow longer than the cells on the light side. C Tropisms Plants need light and water for photosynthesis. They have developed responses called tropisms to help make sure they grow towards sources of light and water. There are two main types of tropisms: light gravity • positive tropisms – the plant grows towards the stimulus positive phototropism (grow negative geotropism (grow • negative tropisms – the plant grows away from the towards the light) against the force of gravity) stimulus. Phototropism is a tropism where the stimulus is light. A positive geotropism (grow in negative phototropism (grow geotropism is a tropism where the stimulus is gravity. the direction of the force of away from the light) The roots and shoots of a plant respond differently to gravity) the same stimuli. The table summarises these differences. Controlled in tips and roots Plant Growth by a plant hormone called auxin. B1 – Understanding Ourselves Use Explanation Weedkillers Selective weedkillers attack some plants and not others. Contains a growth hormone that causes plants to grow too quickly and die. Rooting Powder Dip a cutting in rooting powder to rapidly produce roots so it can be planted and grow. Helps with cloning plants. Ripening Fruits are sprayed with hormones to either delay or speed up ripening so they are ready to sell. Dormancy A hormone called gibberellin can help seeds become dormant out of season. Variation is caused by… • Genes being mixed up when sex cells (sperms and eggs) are made • Genes coming from both parents during fertilisation • Changes in genes called mutations • • • • • • Nucleus houses genetic material Most animal cells have 46 chromosomes or 23 pairs in the nucleus Chromosomes carry different genes which code for our features Genes are made of DNA DNA is made of base pairs wound in a double helix We have different versions of the same gene called alleles B1 – Understanding Ourselves Environmental and inherited characteristics: Some characteristics of an individual are caused by the environment. For example, the language we use or whether we have scars are environmental characteristics. Other characteristics are inherited…the shape of the earlobes, eye colour, nose shape. Some characteristics - including intelligence, body mass and height - are the result of both environmental and inherited factors. But there is debate about the relative importance of these two types of factor in some human characteristics, such as intelligence, health and sporting ability. Gender determination Female gametes (eggs) contain X chromosomes, while male gametes (sperm) contain either X chromosomes or Y chromosomes. This genetic diagram shows that equal numbers of male and female offspring should be produced. Alleles: • Different versions of the same gene • Mostly have 2 of each gene – 1 from each parent • If the alleles are different you have instructions for 2 different versions of the characteristic • The version of the characteristic that appears is caused by the dominant allele • The other allele is recessive • Recessive alleles are only shown if there are not dominant alleles Example for blue eyes… • BB = Homozygous Dominant • Bb = Heterozygous • Bb = Homozygous Recessive Cystic Fibrosis Huntington’s Disease Cystic fibrosis is an inherited disorder caused by a recessive allele. Symptoms: • Thick sticky mucus in the airways and pancreas • Poor digestion • Terrible cough • Prone to infections This genetic diagram shows the possible outcomes when both parents are heterozygous for the faulty allele. There is a one in four chance of the offspring being homozygous for the faulty allele, and so having cystic fibrosis. Huntington’s disease is an inherited disorder caused by a dominant allele. It normally appears during middle age. Symptoms: • Tremors • Clumsiness • Mood changes • Memory loss • Inability to concentrate In this example (represented on a Punnett square), one parent - the mother carries one copy of the Huntington’s allele and has the disorder. B1 – Understanding Ourselves The father does not carry the Huntington’s allele, so he does not This genetic diagram shows have the disorder. the possible outcomes when There is a 1 in 2 or 50 only one parent carries the per cent chance of the faulty allele. There is no couple producing a chance of the offspring child with the being homozygous for the disorder. faulty allele and therefore having cystic fibrosis. Genetic testing Scientists are now able to test adults and unborn babies for alleles that can cause genetic disorders. However, the scientific information produced raises many issues that science cannot address. For example, should a couple with a one in four risk of having a child with cystic fibrosis take the gamble, or decide not to have any children at all? If a woman becomes pregnant with a child that is going to have cystic fibrosis, should she have the child, or choose to have an abortion? These are questions about values that science cannot answer. Different people will have different views.