My Science School

Medical science has only really understood the importance of vitamins in this century, even though human beings have needed and using them since human life first appeared millions of years ago.

It is now known that we need over twenty vitamins. Some help us grow and develop. Some protect us against illness and disease. We cannot make the vitamins we need in our own bodies, so we have to get them from our food. We only need tiny amounts of them each day. But just those small regular doses help keep us healthy.

One of the first vitamin discoveries came from sea voyages. Sailors could not eat fresh fruit and vegetables while they were away from land for long periods. After a few weeks they began to fall ill with a disease called scurvy. Three hundred years ago some ships started carrying orange and lemon juice on voyages. The crews drank this every day and very few men went down with scurvy. The fruit juice obviously did them good. Now it’s known that scurvy is caused by a short age of vitamin C. That is why fruit, especially oranges and lemons, and green vegetables are so good for us.

 

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Thirdhand smoke is residual nicotine and other chemicals left on indoor surfaces by tobacco smoke. People are exposed to these chemicals by touching contaminated surfaces or breathing in the off-gassing from these surfaces. This residue is thought to react with common indoor pollutants to create a toxic mix including cancer causing compounds, posing a potential health hazard to nonsmokers — especially children.

Thirdhand smoke clings to clothes, furniture, drapes, walls, bedding, carpets, dust, vehicles and other surfaces long after smoking has stopped. The residue from thirdhand smoke builds up on surfaces over time. To remove the residue, hard surfaces, fabrics and upholstery need to be regularly cleaned or laundered. Thirdhand smoke can't be eliminated by airing out rooms, opening windows, using fans or air conditioners, or confining smoking to only certain areas of a home.

Thirdhand smoke is a relatively new concept, and researchers are still studying its possible dangers. In the meantime, the only way to protect nonsmokers from thirdhand smoke is to create a smoke-free environment.

 

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VOCs include a variety of chemicals that can cause eye, nose and throat irritation, shortness of breath, headaches, fatigue, nausea, dizziness and skin problems. Higher concentrations may cause irritation of the lungs, as well as damage to the liver, kidney, or central nervous system. Long-term exposure may also cause damage to the liver, kidneys or central nervous system.

Some VOCs are suspected of causing cancer and some have been shown to cause cancer in humans. The health effects caused by VOCs depend on the concentration and length of exposure to the chemicals.

Most people are not affected by short-term exposure to the low levels of VOCs found in homes. Some people may be more sensitive, such as people with asthma. For long-term exposure to low levels of VOCs, research is ongoing to better understand any health effects from these exposures.

 

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Volatile organic compounds are compounds that have a high vapor pressure and low water solubility. Many VOCs are human-made chemicals that are used and produced in the manufacture of paints, pharmaceuticals, and refrigerants. VOCs typically are industrial solvents, such as trichloroethylene; fuel oxygenates, such as methyl tert-butyl ether (MTBE); or by-products produced by chlorination in water treatment, such as chloroform. VOCs are often components of petroleum fuels, hydraulic fluids, paint thinners, and dry cleaning agents. VOCs are common ground-water contaminants.

Organic chemicals are widely used as ingredients in household products. Paints, varnishes, and wax all contain organic solvents, as do many cleaning, disinfecting, cosmetic, degreasing, and hobby products. Fuels are made up of organic chemicals. All of these products can release organic compounds while you are using them, and, to some degree, when they are stored.

EPA's Total Exposure Assessment Methodology (TEAM) studies found levels of about a dozen common organic pollutants to be 2 to 5 times higher inside homes than outside, regardless of whether the homes were located in rural or highly industrial areas. Additional TEAM studies indicate that while people are using products containing organic chemicals, they can expose themselves and others to very high pollutant levels, and elevated concentrations can persist in the air long after the activity is completed.

 

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Each year, close to 4 million people die prematurely from illness attributable to household air pollution from inefficient cooking practices using polluting stoves paired with solid fuels and kerosene.

Around 3 billion people still cook using solid fuels (such as wood, crop wastes, charcoal, coal and dung) and kerosene in open fires and inefficient stoves. Most of these people are poor, and live in low- and middle-income countries.

These cooking practices are inefficient, and use fuels and technologies that produce high levels of household air pollution with a range of health-damaging pollutants, including small soot particles that penetrate deep into the lungs. In poorly ventilated dwellings, indoor smoke can be 100 times higher than acceptable levels for fine particles. Exposure is particularly high among women and young children, who spend the most time near the domestic hearth.

3.8 million people a year die prematurely from illness attributable to the household air pollution caused by the inefficient use of solid fuels and kerosene for cooking. Among these 3.8 million deaths:

• 27% are due to pneumonia


• 18% from stroke


• 27% from ischaemic heart disease


• 20% from chronic obstructive pulmonary disease (COPD)


• 8% from lung cancer.

 

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This combination product is used to treat minor wounds (e.g., cuts, scrapes, burns) and to help prevent or treat mild skin infections. Minor skin infections and wounds usually heal without treatment, but some minor skin wounds may heal faster when an antibiotic is applied to the affected area. This product contains antibiotics that work by slowing or stopping the growth of bacteria.

Topical antibiotics are often applied to wounds after surgery because it is thought that they prevent surgical site infection. There are thought to be benefits in using antibiotics topically rather than orally or intravenously. As topical antibiotics act only on the area of the body where they are applied, there is less likelihood of unwanted effects that affect the whole body, such as nausea and diarrhoea. Topical antibiotics are also thought to reduce the chances of bacterial resistance (bacteria changing to become resistant to medication). However topical antibiotics can also have unwanted effects, the most common being an allergic reaction on the skin (contact dermatitis), which can cause redness, itching and pain at the site where the topical antibiotic was applied.

 

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An abrasion is a superficial rub or wearing off of the skin, usually caused by a scrape or a brush burn. Abrasions are usually minor injuries that can be treated at home. The skin may bleed or drain small amounts at the time of the injury or at times over the next few days if rubbed or scratched. 

Abrasions are very common injuries. They can range from mild to severe. Abrasions are most likely to occur on the:

• elbows


• knees


• shins


• ankles


• upper extremities

Abrasions can be painful, since they sometimes expose many of the skin’s nerve endings. However, they don’t typically cause much bleeding. Most abrasions can be treated at home.

Abrasions aren’t usually as serious as laceration or incision wounds. These are cuts that typically affect deeper skin layers. They may cause intense bleeding and require medical care.

 

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Scars form when the dermis (deep, thick layer of skin) is damaged. The body forms new collagen fibers (a naturally occurring protein in the body) to mend the damage, resulting in a scar. The new scar tissue will have a different texture and quality than the surrounding tissue. Scars form after a wound is completely healed.

There are different kinds of scars. Most scars are flat and pale. However, in cases when the body produces too much collagen, scars can be raised. Raised scars are called hypertrophic scars or keloid scars. Both of these kinds of scars are more common in younger and dark-skinned people.

Some scars can have a sunken or pitted appearance. This kind of scarring occurs when underlying structures supporting the skin (for example, fat or muscle) are lost. Some surgical scars have this appearance, as do some scars from acne.

Scars also can appear as stretched skin. Such scars result when the skin stretches rapidly (for example, as in growth spurts or during pregnancy). In addition, this type of scar can occur when the skin is under tension (near a joint, for example) during the healing process.

 

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Pus is a whitish-yellow, yellow, or brown-yellow protein-rich fluid called liquor puris that accumulates at the site of an infection.

Pus is the result of the body’s natural immune system automatically responding to an infection, usually caused by bacteria or fungi.

Leukocytes, or white blood cells, are produced in the marrow of bones. They attack the organisms that cause infection.

Neutrophils, a type of leukocyte, have the specific task of attacking harmful fungi or bacteria.

For this reason, pus also contains dead bacteria.

Macrophages, another type of leukocyte, detect the foreign bodies and release an alarm system in the form of small, cell-signaling protein molecules called cytokines.

Cytokines alert the neutrophils, and these neutrophils filter from the bloodstream into the affected area.

The rapid accumulation of neutrophils eventually leads to the presence of pus.

 

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When sports professionals or teachers refer to fitness they divide the topic into three separate areas. These categories are Stamina, Strength and Flexibility.

Stamina (or endurance)

Stamina is the ability of your body to continue physical activities for an extended time. To improve your stamina you need to do more aerobic exercise.

Aerobic exercises Include brisk walking, jogging, swimming, cycling and even dancing. There are many classes offering different styles of aerobic exercise depending on your fitness level.

Aerobic exercises strengthen your lungs and heart, which means that more blood and oxygen can be pumped around your body to where and when it is needed most, and you can work for longer length of time without getting out of breath.

Strength (or power)

To increase your strength and power, and build up your muscles you need to concentrate on anaerobic activities. Strong, well developed muscles support your joints and lessen the risk of injury when you are doing sudden, explosive movements like sprinting or simply when you are lifting things.

If you have not finished growing it is ill advised to take up lifting weights, as you can do serious damage to your body

The best and fortunately the cheapest way to build up strength is to use your own body in resistance when training, eg push-ups, where your arms are pushing against the weight of your body.

Flexibility (or suppleness)

Flexibility is your bodies ability to go through all its regular movements without feeling any sort of pain. Stringy tissues called tendons fasten your muscles to your bones, without regular movement they can get tight and make it harder to do things like touch your toes or scratch your back.

Gentle stretching eases stiffness. You should always warm up your body gently before you start any physical activity.

 

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