Drugs How they work Objectives: *Define the term drug **Describe the medicinal use of antibiotics for the treatment of bacterial infection ***Explain why antibiotics kill bacteria but not Viruses Starter: What is a drug?

Drugs Dangers of drugs Alcohol Cannabis Cocaine and heroin Tobacco Alcohol and tobacco are legal drugs. Cannabis, cocaine and heroine are illegal. People can become addicted to a drug. They feel dependent on it. Drug addiction can have long term effects. They can affect the brain and liver. The liver is damaged as its job is destroying harmful chemicals within the body. Legal drugs can be misused and become a danger. A drug is something that alters or influences the chemical reactions in the body. Recreational drugs are taken for pleasurable reasons. Drugs are either depressant or stimulants

What is a drug? Name 1 that is legal Name 1 that is illegal Starter What is a drug? Name 1 that is legal Name 1 that is illegal http://www.youtube.com/watch?v=4jH1zqlfQI

A drug is any chemical that alters how our body works. Drugs that affect our CNS control the movement of chemicals across the synapse. These are called recreational drugs e.g. hallucinogens The natural chemicals in our nervous system have shapes that fit like a key in a lock . Drugs have a similar shape to these chemicals and mimic (copy) what they do.

I can describe different types of drugs and why some people use them for recreational drugs Task Two What drug?

Nicotine- affects the brain. It is addictive. Cigarette poisons Tobacco contains many different substances including nicotine, tar and carbon monoxide in smoke particles Nicotine- affects the brain. It is addictive. Lung diseases A smoker get lung infections. In the bronchitis, the smokers bronchi inflames. Lots of mucus is produced. This can cause excessive coughing. The air sacs lose stretchiness. It is difficult to get oxygen into the blood. This is called emphysema. Someone with this condition may have to breathe oxygen from a cylinder. Tar – is a poison that causes cancer. Its a carcinogen. Cigarette smoke often causes lung cancer, but can risk development of other cancers. Carbon monoxide- takes the place of oxygen in red blood cells, so the blood carries less oxygen. This can harm body cells. In pregnant women this can be dangerous as the baby will get less oxygen, it may not grow properly and have a low birth weight. A person who smokes is likely to have heart disease. Smoke particles – burnt fragments of tobacco Accumulate in the lung tissue and stimulate body’s defence system to remove them.

Increases aggression in some, Alcohol: Quickly absorbed through the cell wall of stomach-carried by blood-eventually broken down by liver-but this takes quite a long time. Alc. lengthens reaction time, it is a depressant, to respond to a stimulus. Increases aggression in some, More than 0.8 over 2 hours-unconscious-death is caused by vomiting while unconscious-airways are blocked Alcoholism –dangerous disease. Liver cirrhosis, where fibres grow in liver, can be fatal. Damages brain too. Alcohol draws water out of cell by osmosis, when it happens to brain cells, they shrink and may be irreversibly damaged. Alcohol also inhibits the release of a hormone which stops kidney from allowing too much of water to leave the body in the urine-dilute urine-so low levels of water in the blood.

Most of the antibiotics are made from Fungi. Bacteria n Fungi-both r decomposer-they compete for foods We use the chemical warfare system of Fungus to fight with bacteria Penicillin was the first discovered antibiotic from fungus Penicillium It kills bacteria by stopping them making their cell walls. Misuse of antibiotics-against viral as well as bacterial diseases-made it resistant Need newer antibiotics

Pathogens & Antibiotics Microorganisms and disease Some bacteria and viruses can cause disease. A microorganism that causes disease is called a pathogen. If bacteria can get into the body, it reproduces rapidly. They produce toxins that make you feel ill. They are carried in the blood. A virus can get into a cell and reproduce there. When too much is produced they can burst out of the cell and destroy it. Microorganisms These are living things that we cannot see. They include fungus, bacteria and viruses Their cells are smaller than ours. You can’t see bacteria clearly. Viruses are even smaller. There are some viruses that can get into bacteria, so bacteria can also get ill. Antibiotics These are drugs that kill bacteria and fungus inside your body. They don’t kill viruses. Antibiotics include penicillin and streptomycin. We different ones as they don't all work equally well against all kind of bacteria. The antibiotics that can only kill specific bacteria are or fungus are called narrow spectrum antibiotics. Broad spectrum antibiotics can kill a larger variety of pathogen Antibiotics work either by damaging the cell wall or inhibiting the metabolism in a cell of the pathogen. Since viruses do not have cells and they occupy host cells antibiotics can not work on them . If they did the host cell would be affected

Drugs against disease Antiviral Viruses are more difficult to kill. Painkillers A drug used to get rid of pain. You can buy these, e.g. Aspirin, paracetamol and ibuprofen. They reduce symptoms of whatever is wrong with you. Sources of antibiotics Penicillin is made from a fungus. The drug companies are always on the look out for new antibiotics. Nowadays, most antibiotics are made chemically. This is better then extracting them from fungi or other organisms because you know what you're getting. If you take it from fungus, you don’t know the strength of it. Making it chemically means you know its pure Antiviral Viruses are more difficult to kill. If they go inside a cell they are impossible to kill it without killing the cell. Antivirals are used to kill viruses.