Por ultimo, la empresa agropecuaria debe contar con un plan de trabajo específico en donde se tengan claramente definidos cuales son sus objetivos y

Drug is externally administered chemical substances that modifies/affects chemical reactions in the body.

14.2 MEDICINAL DRUGS

- drugs taken under medical supervision to treat diseases, relieve pain and in surgery.

Antibiotics

- Antibiotics are chemicals, usually produced by certain bacteria and moulds, that are used to treat many infectious diseases caused by microorganisms

• Antibiotics aren’t useful on viruses. When a person acquiring viral infection given antibiotic: prevent him getting bacterial infection as his resistance is very lowered.

Four types of antibiotics:

- Penicillin made by fungus Penicillum. They interfere metabolic functions of microorganisms from producing enzyme to synthesize their cell wall.

- Cephalosporins made by mould Cephalosporium. Useful against bacteria which have developed resistance against penicillin.

- Tetracyclines made by bacterium Streptomyces aureofaciens. They attack a wide variety of bacteria, therefore called broad-spectrum antibiotics.

- Erythromycins attack bacteria affected by penicillin. They are useful against bacteria which have developed resistance against penicillin.

Antibiotics work in 2 ways:

- Prevents bacterium from making essential components of the cell wall which makes it easier for body’s immune system to destroy it. E.g. penicillin

- Damages protein-producing machinery inside cytoplasm of bacterium, preventing it from dividing. E.g. tetracycline

Anaesthetics and Analgesics

Anaesthetics are drugs that make body unable to feel pain, e.g. novoacain and cocaine causes loss of sensation around injected area. Applied for tooth extraction.

Analgesics relieve pain without causing numbness/affecting consciousness, e.g.

aspirin relieves minor pain and reduces fever. If taken in large dose causes side effect

14.3 ALCOHOL

Alcohols are rapidly absorbed into bloodstream from intestine & broken down in liver The Effects of Alcohol on the Nervous System

- Alcohol is a depressant which slows down brain functions

• It causes increased anxiety

• It reduces nervous tension and worries and stimulates appetite

• It makes the drinker carefree as alcohol takes away his inhibitions

• It reduces the drinker’s self-control which causes a person to take personal and social liberties which they may regret when alcohol effects have worn off.

- Increased consumption of alcohol creates observable effects of intoxication

• It causes slurred speech

• It causes blurred vision and poor muscular co-ordination – the person becomes clumsy and unable to walk properly

• It deters the drinker’s judgement, e.g. he underestimates speed causing speeding - More areas of brain are pulled, drinker becomes anaesthetized and unconscious

• High alcohol levels paralyzes medulla oblongata or hind brain, which controls breathing and heartbeat, contributing to death

- Frequent consumption of alcohol makes a person addicted

• They neglect work & families - exhibit violent behaviours towards family members

• They commit crimes under influence of alcohol The Effects of Alcohol on the Digestive System

• Stimulates acid secretion in stomach – increased risk of gastric ulcers

• Prolonged alcohol abuse damages liver leading to liver cirrhosis (disease in which liver cells destroyed and replaced with fibrous tissues making liver less functioning).

It can cause haemorrhage in liver and liver failure – causing death Withdrawal Symptoms

When a person stops drinking alcohol, they experience symptoms (e.g. illness, mental disturbance, etc.) which makes it hard for them to give up their drinking habit.

14.4 ABUSE OF DRUGS Drug abuse can cause:

- Tolerance – condition where a person has to keep on taking more and more of a drug to achieve the same effect

- Addiction/Dependance – condition where a person experiences withdrawal symptoms (e.g. physical illness – nausea, vommiting, uncontrolled trembling;

mental disturbance – cause anxiety, depression) if he does not take the drug Types of Drugs

Stimulant Drugs: These drugs stimulate CNS, e.g. cocaine, amphetamine.

- Amphetamines are used to counteract depression and hunger, and prevent fatigue Depressant Drugs: Drugs which slows down brain functions and induce sleepiness.

- Alcohols and sleeping pills can make you sleepy

Hallucinogenic Drugs: These drugs cause a person to experience hallucinations, illusion and distorted images.

- E.g. Marijuana, Lysergic Acid Diethylamide (LSD)

Opiates: These are narcotic drugs which relieve pain and induce sleep and stupor.

- E.g. Opium, Morphine, Heroin Heroin – The Opiate

Heroin is a powerful depressant which sedates and relieves pain Danger

- User commit crime under drug influence as they need money to get heroin supply.

- User becomes rapidly addicted & needs larger dosage to produce same sensation - User has to use the drug more often to avoid withdrawal symptoms (i.e. anxiety,

stomach upsets, sweating, goosebumps, watering of eyes, vommiting, diarrhoea, convulsion, hallucinations and death), leading them to misery as they desperately need to obtain more money for the drugs, so they turn to crime

- Injecting shared unsterilized and contaminated needles into vein results in transmission of hepatitis B and human immunodeficiency virus (HIV) causing AIDS (Acquired Immune Deficiency Syndrome)

14.5 SMOKING

Why do young people smoke?

- They smoke as they believe smoking is a symbol of adulthood, under the effect of advertisements from cigarette companies trying to give impression that maturity, social status, happiness and success are linked with smoking.

- They smoke to cover their weaknesses such as failing in studies or sports.

- They smoke out of curiosity as they want to experience what smoking is all about, but addictive drugs in smoke makes smokers difficult to give up smoking.

- They imitate their parents who smoke.

- They want to be accepted as members of group of friends who smoke as their friends’ persistent teasing and urging make them not sporting enough if they don’t smoke. This is called ‘peer group’ pressure.

A Goodbye From Being Socially Acceptable... Why Could This Happen?

Smoking’s no more considered fashionable due to harm to smokers & people around - Scientists provide scientific evidence on harmful effects of smoking, therefore

making people aware of dangers of smoking to health.

- Smoking has been recognised to have been causing significant number of death and disability around the world by lung and heart cancer.

- Smoking harms people around smokers by passive smoking, that is, non-smokers breathe in smoke exhaled by smokers, exposing them to smoking-related diseases.

What is in That Smoke?

- Nicotine

This is addictive drug present in tobacco.

Profession:

• First stimulates the brain, making smoker feel alert and relaxes muscles, while later dulls the brain and senses

• Causes release of adrenaline – increasing heartbeat rate and blood pressure

• Makes blood clot easily – increasing risk of blood clots blocking blood vessels, leading to heart attack if clots block coronary arteries, or stroke if clots block capillaries of the brain

- Carbon Monoxide Profession:

• Reduces the capacity of haemoglobin transporting oxygen

• Speeds fat deposition on inner arteries walls, narrowing lumen (atherosclerosis)

• Damage lining of blood vessels – increase tendency of blood clot & block vessels - Tar

This is brown sticky substance that accumulates in lungs during smoking Profession

• Cell division in lungs continuously replase air sacs membrane. Tar containing many carcinogenic(cancer-causing) chemicals induces cells to divide at abnormal rate. Uncontrolled multiplication of cells causes outgrowths of tissue (cancer) which block off air sacs, reducing efficiency for gaseous exchange

• Paralyse cilia lining, preventing cilia removing dust particles from lungs & trachea - Irritants (e.g. hydrogen cyanide, acrolein)

Profession:

• Paralyse cilia in air passages and weaken walls of alveoli

• Irritate cells lining air passages causing them to produce mucus which in turn causes smokers’ cough which bursts the weakened walls of alveoli causing a decrease in wall area as many minute alveoli coalesce to form reduced number of enlarged alveoli, reducing surface for gaseous ecxhange in lungs. (emphysema) Smoking-Related Diseases

- Lung cancer

Carcinogenic substances in cigarette smoke may cause abnormal growth of bronchial tube wall. The growth blocks bronchial wall, making breathing difficult.

Without immediate treatment, the cancer may spread to other neighboring cells and organs, increasing risk of mouth, throat, pancreas, kidney & urinary bladder cancer.

- Chronic bronchitis

epithelium lining bronchi inner surfaces to lungs become inflamed & narrowed, and excessive mucus is produced, reducing air flow in air passages making breathing difficult and forces a person to cough and sneeze persistently to clear air passages, making lungs more likely infected by bacteria. It also increase production of pleghm.

- Emphysema

it is associated with chronic bronchitis and smoking. The partition walls between alveoli break down due to intense coughing, enlarging air spaces and decreases surface area of lungs, thus reducing absorption of oxygen. Lungs over-inflated with air and lose elasticity and makes breathing difficult. The person spends lots of energy to breathe & sneeze, and he suffers severe breathelessness/slight exertion.

Smoking and Pregnancy

Effect of Carbon Monoxide on fetus:

Carbon monoxide combines with haemoglobin to form carboxyhaemoglobin which cannot transport oxygen, reducing amount of oxygen reaching fetus through placenta.

Effect of Nicotine on fetus:

Nicotine causes arteries bringing blood to placenta narrower – food substances reaching fetus is reduced. The mother suffers lack of oxygen or chronic bronchitis.

Dangers of smoking to fetus:

- Fetus brain development affected – child may have learning difficulties in later life - Fetus grows more slowly causing underweight & may die within first few days of life.

- There is higher risk of baby born prematurely - There is greater risk of miscarriage

- The baby has greater risk of being born dead.

CHAPTER 15: MICROORGANISMS AND BIOTECHNOLOGY