Category Zoology

Why do old people get shorter?

            The spine becomes shorter in older people because the pad of cartilage between the bony vertebrae grows thinner. Older people often lose bone in a condition called osteoporosis. This usually affects elderly women, although it can also appear in men. The bone becomes spongy, and when it affects the vertebrae in the spine they may collapse. This causes pain, and also makes the person’s spine shorter and curved. Osteoporosis can be treated with drugs, and a diet containing the mineral calcium can also help. Calcium is plentiful in milk and cheese.

Do people become forgetful in old age?

            It is very common for old people to become forgetful, although many retain perfect memories from long ago.

            Many things can cause forgetfulness. Sometimes the blood supply to the brain is not effective. The brain cells become starved of oxygen and nutrients, leading to dizzy spells and forgetfulness. Dementia is a condition where forgetfulness becomes a serious problems, and the person may not be able to look after himself or herself. Alzheimer’s disease is the most serious form of dementia. For most old people, memories bring great pleasure. Strangely, even though recent events may be forgotten, old people often clearly remember events that took place in their childhood.

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Why do people grow old?

            Ageing is a result of the gradual failure of the body’s cells and organs to replace or repair themselves. This is because there is a limit to the number of times that each cell can divide. As the body’s cells begin to near this limit, the rate at which they divide slows down. Sometimes the new cells that are produced have defects or do not carry out their usual task effectively. Organs can then begin to fail, tissues change in structure, and the chemical reactions that power the body become less efficient.

How does the body change with increasing age?

            Older people are no longer growing, and so they are not as active as they used to be. For this reason they do not need to eat as much, and quite often become thinner. The body loses muscle as well as fat, and sometimes older people become unsteady on their feet.

Why does the skin become wrinkled?

            The skin becomes looser as people age. As skin sags it forms into wrinkles and creases. This happens because the fibres of collagen that normally provide support to the skin become weaker. Smoking and over-exposure to the Sun can make skin more likely to wrinkle.

What is an antibiotic?

                     Antibiotics kill bacteria by interfering with the way in which bacteria reproduce. Antibiotics are produced naturally by many simple plants and even other bacteria. Antibiotics are useful because they seldom have any bad effect on the person taking them. The use of antibiotics has meant that many diseases that were usually fatal can now be cured.

                   Antibiotics work by damaging bacterial reproduction rather than killing the bacteria outright, and so it is important to take the full course of the drug. Often you will feel better within a couple of days of starting treatment, but if you stop too soon the bacteria can recover. When you keep taking the drug, after several days the bacteria die and are cleared away.

How was penicillin discovered?

                        Penicillin was the first antibiotic to be discovered, by Alexander Fleming. He was searching for substances that would kill bacteria when he noticed some mould growing on an experimental dish. The mould killed the colonies of bacteria that were growing around it. Penicillin was extracted from this mould, and its use has saved millions of lives. Many other antibiotics have since been discovered or made artificially.

Are all drugs dangerous?

                       People take so-called recreational drugs, such as cannabis and heroin, because of the effect they have on the brain. (These drugs are different from medical drugs that people take when they have an illness or disease.) Recreational drugs can be a danger to health. Some of them make people feel excited and full of energy. Others make them feel sleepy, and some drugs can make people experience imaginary situations. All these drugs cause the brain to malfunction, and if taken regularly they can cause permanent damage to health.

                      Some of these drugs are addictive. This means that they cause changes in the brain that make people crave them, even though the pleasant effects may wear off.

How do medical drugs work?

                     Many medical drugs work by correcting the chemical reactions within the body that are responsible for disease. For example, insulin injections replace insulin that is not being produced by the pancreas, so sugar can be used properly by the body. In depression and mental illness, drugs can restore the balance of chemicals in the brain. Aspirin is often given to cure a headache, but it can also neutralize the inflammation that causes pain in the joints of people suffering from arthritis.

                       Modern drug research studies the cause of diseases, and then designs molecules that interrupt or reverse the disease process. All drugs cause some unwanted effects, and scientists try to find new drugs that relieve disease without causing further problems.

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Why is smoking harmful?

                             Cigarette smoking is known to be the main cause of lung cancer. It also causes bronchitis, heart disease and other problems with the circulation. Cigarette smoke contains many harmful substances, which are all deposited straight into the lungs. The smoke contains tiny particles of soot that can clog the air passages. The tar in smoke contains substances that can cause cancer. The nicotine in cigarettes is a strong addictive drug that can affect the heart and circulation. However, this addiction can be very difficult to break.

                             The harmful effects of cigarettes may only appear after many years of smoking. However, even when a smoker gives up the habit, it can be years before these health risks are cancelled out.

What is health?

                    Being healthy involves far more that simply not being ill. If you feel in good health, your organs will be working properly and you will have the energy to live life to the full. This feeling of wellbeing affects your mind and your body.

How can I keep myself healthy?

                    The environment you live in, your diet and your lifestyle affect your health. Physical fitness is an important part of health, and this means that your heart, lungs, skeleton and muscles all work together smoothly to carry out your daily activities. Fitness involves strength, stamina and suppleness, and you need regular exercise to maintain all these conditions. Careful exercise develops a healthy heart and lungs, and gives you the strength and stamina that allow you to run, cycle and swim. A sensible diet and sufficient sleep also help you to keep healthy.

Can the environment harm health?

                    Air pollution is an environmental factor that can damage health. Exhaust fumes from motor vehicles contain substances that can cause asthma and other breathing problems. In hot climates smog can also develop, trapping these air pollutants and making the health risk greater.

What causes disease?

                      Many diseases are infections that are caused by bacteria or viruses. Other illnesses are caused by failure of some of the body’s organs or tissues. Sometimes parts of the body wear out or are not replaced properly, but most health problems are caused when the body simply fails to maintain itself. Joints can wear out, causing arthritis, or the digestive system may not work as efficiently, causing various types of stomach upset. Other diseases may be caused by a person’s own lifestyle, for example lack of exercise or poor eating habits. Smoking is now known to be a contributory factor in many diseases.

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