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Biology 10th Class Biology

Chapter 18 Pharmacology 10th Class Biology Notes

Chapter 18 Pharmacology 10th Class Biology Notes

Pharmacology 10th Class Biology Notes

Question 1: Define Pharmacology, Pharmacy and Pharmacognosy?

Answer: Pharmacology: Pharmacology is the combination of two Greek words. Pharmakon means drug and logy means to study or to discuss. Pharmacology is the study of drug composition, properties and medical applications.  OR  Pharmacology is the study of action of drug.

Pharmacy: Pharmacy is the study of preparation and dispensing of drugs.

Pharmacognosy: Pharmacognosy is the study of medicines derived from natural sources.

Question 2: Write a note on history of pharmacology?

Answer: History of Pharmacology: Clinical pharmacology was presented in the middle ages (In European history the middle ages or medieval period lasted from 5th to 15th century A.D) Early pharmacologists focused on natural substances, mainly plant extracts. Pharmacology developed in the 19th century as a biochemical science. Oswald Schmiedeberg (1838-1921). German pharmacologist is called father of pharmacology.

Intresting Information: Some medicines are taken before meal (food) because food interact with medicines and alter their chemical compositions. Mostly drugs functions in digestive system are mostly used as such. For these medicines food act as activator. Secondly the medicine easily into blood and other parts. Some medicines are taken after food to reduce irritation and any other damage to stomach and blood vessels. Most of the medicines are taken at night time because at that time flow of blood, action of hormones and enzymes are at normal range. And that is why drug gives a better result. Some drugs due to their sedation (Sedative effects) are taken at night. Other drugs that are relatively slow in action are mostly taken at morning or three times a day. Because during morning and noon time the blood pressure is at high rate. Some drugs also act on enzymes and hormones and inhance their action, so they are taken at specific time to increase activities.

 

Question 3: Define Drug? What are the different types of drugs?

Answer: Drug: Any chemical substance absorbed into the body of living organisms alters normal body functions is called drug.

OR Drug is a chemical substance used in the treatment, cure, prevention or diagnosis of diseases or used to enhance physical or mental well beings.

Explanation: Drug has much broader meaning. Drugs not only include common everyday chemicals that is used to cure diseases but it also include common everyday chemicals that change normal functions like caffeine, nicotine, alcohol and a variety of toxins.

Types of Drugs: Following are two main types of drugs.

Medicinal drug or pharmaceutical drug or Medicine: Any chemical substance used in diagnosis, cure, treatment or prevention of diseases is called Medicine.

Addictive drug: Drugs which the person becomes dependent or addicted are called addictive drugs. The uncontrollable desire for drug is called drug addiction.

 

For Your Information:

Difference between pain and Ache: Pain occurs suddenly. E.g. hit thumb with hammer. Pain is local or small area or wide spread. Ache is related to a particular part. They disappear for some time but recover again. Ache is long lasting. A dull pain is called ache.

 

For Your Information:

GABA: Sedative drugs effect the GABA (Gamma amino butyric acid ) GABA are neurotransmitters chemicals that conduct communication between brain cells.

 

 

For Your Information:

Pharmacology is not synonymous with pharmacy, which is the name used for a profession, though in common usage the two terms are confused.

 

Researchers of a pharmaceutical company spent two years testing soil from all parts of the world to find new antibiotics. The project resulted in the development of one antibiotic, Terramycin, which is used to treat many infections.

 

Until 1890, the subject of pharmacology was known as Materia Medica. Prescription drugs are sold only on physician’s prescription. These include barbiturates, tranquillizers, antibiotics etc. Non-prescription drugs are sold over the counter because these are considered safe enough. These include aspirin and some cough medicines.

 

 

 

Question 4: What are the sources of drugs? Give examples.

 

Answer: MEDICINAL DRUGS: Various diseases have been made easier to treat in recent years by the production of medicinal drugs. Drugs are obtained from the following sources.

 

  1. Synthetic Drugs

Such drugs do not occur naturally but are synthesized in laboratory. Pharmaceutical companies produce these drugs e.g. aspirin.

 

  1. Drugs from Plants and Fungi

Many types of drugs like antibiotics, cardiotonics and certain analgesics are obtained from plants and fungi. The antibiotic penicillin comes from a fungus called penicillium nutatum. The cardiotonic (digitoxin) is used to stimulate the heart. It is made from the leaves of purple flowered plant, foxglove (Digitalis purpurea). The pain reliever morphine is made from opium, which comes from the juice of opium poppy plant (Papaver somniferum).

 

  1. Drugs from Animals

Drugs obtained from animals are usually their glandular products. Fish liver oils, musk, bees’ wax, certain hormones and antitoxins are obtained from animal sources.

 

  1. Drugs from Minerals

Mineral sources include acids, bases, salts, etc. Several common drugs are produced from minerals.

The mineral iodine is used in making tincture (alcoholic extracts of plants or animals) of iodine, a liquid that helps prevent infection when applied to cuts and bruises.

The powder form of silver nitrate is applied on wounds to stop bleeding and prevent infection.

 

  1. Drugs from Bacteria

Many antibiotics are obtained from bacteria. e.g. streptomycin from streptococcus.

 

Very Intresting Information: * Insulin are obtained from pancreas of cattles.

** Chorionic gonadotropin (CHG) used for treatment of infertility is obtained from urine of pregnant women.

 

Question 5: Write about usage of important medicinal drugs? OR Classify drugs on the basis of their chemical properties and modes of action?

Answer:

 

Principle usage of important Medicinal Drugs

Drugs are classified on the basis of their chemical properties and modes of action.

  • Analgesics: The medicines (painkillers or pain relievers) reduce pain e.g. aspirin, paracetamol etc.
  • Antibiotics: These medicines inhibit or kill bacteria and treat bacterial infections. Antibiotics are natural substances produced by bacteriaand fungi e.g. tetracycline, cephalosporin etc.
  • Sedatives: These drugs induce sedation by reducing irritability or excitement. These are central nervous system depressants. e.g. diazepam.
  • Vaccines: These drugs are used to develop immunity against viral and bacterial infections e.g. vaccines against small pox, whooping cough, hepatitis B etc.
Things to remember !

Medicines can help you feel better. But if medicines are taken incorrectly, they can actually make you feel worse. It is important to:

• Always check the instructions on doctor’s prescription slip and make sure you take the doses of medicine strictly as your doctor prescribed.

• Always check the expiry date printed on the medicine pack. The expired medicines may prove poisonous.

• Never take medicines prescribed for someone else, even if you think you have the same medical problem.

• Some medicines – such as antibiotics – must be taken for a specific number of days. Make sure you take the medicine for the stated time. Otherwise the problem may come back again.

• Always check with your doctor before you stop taking a medicine or consider a new treatment.

• Some medicines are not suitable for children, and there are special children’s dosages for many medicines.

• Do not take medicine in the dark.

• If your prescription medicines are crucial for your health and life, carry medicines and dosage instructions with you, whenever you are out of home.

• Always keep healthcare products out of the reach of children.

• Do not use the medicine if there are signs of tampering. Inform the pharmacist and the manufacturer of the medicine, about it.

 

For your information:

 Joseph Lister(1827 – 1912) was an English surgeon. He promoted the idea of sterile surgery for the first time. He introduced carbolic acid to sterilize surgical instruments and to clean wounds.
Antiseptics reduce the possibility of infections on skin.

Antibiotics inhibit or kill bacteria within or on the body.

Disinfectants destroy microorganisms found on non-living objects.

 Sir Alexander Flemming(1881 – 1955) was a Scottish biologist. He discovered the antibiotic penicillin from the fungus Penicillium notatum, for which he was awarded the Nobel Prize in 1945.

 

Question 6: Write a note on sedatives, narcotics and hallucinogens. OR what are the different types of addictive drugs?

Answer: ADDICTIVE DRUGS: Addictive drug: Drugs which the person becomes dependent or addicted are called addictive drugs. The uncontrollable desire for drug is called drug addiction.

Categories or types of addictive drugs: The following are major categories of addictive drugs:

  1. Sedatives. 2. Narcotics. 3. Hallucinogens.

 

Sedatives: These drugs induce sedation. These interact with central nervous system to depress its activities, so brings a feeling of relaxation.

Effects of sedatives: Sedative drugs induce dizziness, lethargy, slow brain function and depression. Long-term use of sedative induce suicidal thoughts. One of the most marked effect is that a person needed to create the desire effect and this can cause him drug addictor.

 

Examples: Diazepam (valium), Alprazolam (Xanax), Ethanol, etc.

 

Narcotics: Narcotics are strong painkillers, induce sleep and cause dullness to senses. These drugs act on CNS, so these are often used with less potent pain killers (paracetamol or aspirin).

Uses: These are often used to relieve pain in chronic diseases such as cancer. These are also used to relieve pain after operation.

 

Addictive uses of narcotics: Some people use narcotics as addictive drugs. Narcotics drugs give euphoria (sense of wellbeing) and provide a day dreamy escape for reality for some time. After successive doses taken a person becomes addicted.

Examples of narcotics: Examples of narcotics are morphine and codeine. These are obtained from opium.

 

Morphine: Morphine acts directly on CNS to relieve pain. Morphine has a high potential for addiction. The most commonly abused narcotic. I.e. heroin is a semisynthetic drug from morphine. It effect the central nervous system and cause drowsiness.

Codeine: Codeine is also an opiates mostly used in cough medicines.

 

For your information: In many western countries, heroin is prescribed as a strong analgesic under the name diamorphine. Its use includes treatment for acute pain, such as in severe physical trauma, myocardial infarction, post-surgical pain etc.

 

(3) Hallucinogens: Hallucinogens are the drugs that cause changes in perception, thoughts, emotions and consciousness. Examples: (1) Mescaline obtained from cactus. (2) Psilocin obtained from magic mushroom (Psilocybian). Other examples are Datura, Cannabis, Salvia divinorum, Morning glory, Peyote (a Cactus), etc.

 

Effects of Hallucinogens: Physiologically hallocinogens effects on sympathetic nervous system, causing: (a) Constriction of the some arteries. (b) Rise in blood pressure. (C) Dilation of pupils.

 

 

Interesting information: Hallucinogens effects the interaction between nerve cells and neurotransmitters (serotonin) distributed throughout the brain and spinal cord. Under the influence of hallucinogens people experience hallucination (Hallucinations are perceptions that have no basis in reality, but that appear entirely realistic. For example, they see images, hear sound and feel sensations that seem real but do not exist). Hallucinogens are illegal.

 

Marijuana is one of the most commonly used drugs in the world, following only caffeine, nicotine, and alcoholic beverages in popularity.

Marijuana is a hallucinogen which is smoked. It is obtained from the flowers, stems and leaves of marijuana plants (Canabis sativa and Canabis indica).

Effects of marijuana:

i) Small doses of marijuana result in a feeling of wellbeing that lasts two to three hours. This effect is called “getting high or getting stonned”.

ii) Increase heart rate.

iii) Effects the production of sperms in man.

iv) Weakens short term memory.

v) Getting hungry, having many ideas in mind, expansion of blood vessels in eyes (red eye).

 

Question 7: What are the main problems associated with drug addiction?

Answer:

 

Drug Addiction and Associated Problems: Experts of social sciences prove that there exist a close relationship between drug addiction and crime.

1) Apart from negative physical effects there are psychological and emotional effects on drug users, that is worthlessness, shamelessness, etc. that is often due to the fact that a person knows that drug is destructive thing, yet he do it anyway.

2) Every drug addictor is a law violator and thus every drug is subject to arrest by the police.

3) Most narcotic addict get involved in various types of crime, e.g. robbery, shoplifting, burglary, embezzlement, etc.

4) Drug addicts may commit violent crimes, so many become psychic patients.

5) The drug addicts are very weak in their social behaviors. Drug addicts do not take care any relation. He also tends to destroy already existing relationships.

6) They also face social stigma. The society dislike them because of their unpredictable behaviors.

 

 

For your information: The jails and prisons of our country are full of such people who have committed no other crime than the illegal possession of narcotics.

 

Some antibiotics can be used to treat a wide range of infections and are known as ‘broad-spectrum’ antibiotics. Others are only effective against a few types of bacteria and are called ‘narrow-spectrum’ antibiotics.

The jails and prisons of our country are full of such people who have committed no other crime than the illegal possession of narcotics.

 

Expired drugs can cause damage to kidneys.

The sulfonamide group is also present in other medications that are not antibiotics e.g. thiazide diuretics (medicines for lowering blood pressure).

 

When bacteria are exposed to the same antibiotics over and over, they can change and are no longer affected by the drug.

 

Question 8: Describe the main groups of antibiotics.

`Antibiotics: An antibiotic is a drug that kills or retards the growth (reproduction) of bacteria. They are the chemicals produced by or derived from microorganisms (bacteria and fungi). Some antibiotics also effective against fungal infections called anti-infective.

Classification of antibiotics on the basis of action: Antibiotics are divided into two groups on the basis of action.

 

Bactericidal antibiotics: Bactericidal are those antibiotics that kill bacteria.

Bacteriostatic antibiotics: Bacteriostatics are those antibiotics that stop or inhibit the growth of bacteria.

 

For your information: Bactericidal antibiotics are preferred because they omit the problem from its roots but they will effect the normal microorganisms.

Bacteriostatic antibiotics prepare a proper defense against the invading bacteria. Bacteriostaic antibiotic have minor side effects.

 

Classification of antibiotics on the basis of chemical structure: On the basis of chemical structure antibiotics are of three types.

 

  1. Cephalosporins: Cephalosporins interfere with synthesis of bacterial cell wall and so are bactericidal. Cephalosporins are used to treat pneumonia, sore throat, strep-throat, tonsillitis, bronchitis etc.

 

  1. Tetracyclines: These are broad-spectrum bacteriostatic antibiotics and inhibit bacterial protein synthesis. They are derived from a species of streptomyces. Tetracyclines are used in the treatment of infections of respiratory tract, urinary tract, intestine etc. Tetracyclines are not used in children under the age of 8, and specifically during periods of tooth development.

 

  1. Sulpha Drugs – Sulfonamides:

Sulpha drugs are synthetic antibiotics that contain sulfonamide group. Sulfonamides are broad spectrum bacteriostatic antibiotics. Sulfonamides are the first antimicrobial medicines. They inhibit the folic acid synthesis in bacteria. They are used to treat pneumonia and urinary tract infections.

 

For your information: Cephalosporines is obtained from a fungi called cephalosporium (modern name acremonium) genus of fungi so named cephalosporines.

 

Tonsils: Tonsils of connections of lymphoid tissues facing into the aero-digestive tract. These are present at both sides of the tongue near the windpipe.

 

Tonsillitis: Tonsillitis is a disease of inflamation of tonsils caused by virus or bacteria. Symptoms include sore throat and fever. When caused by bacterium streptococcus then called strep-throat. Most people are recovered without medication.

 

Tetracycline got their name because they share a chemical structure that has four rings.

 

Sulphonamides or sulpha drugs: It contains a large number of chemical substances that cotain sulphur element.

 

Question 9: Write a note on resistance against antibiotics.

Answer: Antibiotic Resistance: Antibiotic plays important role in modern medicines to inhibit growth of bacteria or kill bacteria. But bacteria have capability to develop resistance against antibiotics. Bacteria became antibiotic resistant due to number of ways.

They posses internal mechanism of changing the structure so antibiotics no longer works. They inactivate or neutralize the antibiotics.

Bacteria can also transfer the genes responsible for antibiotic resistance between them. So such resistant bacteria make it possible for other bacteria to acquire resistance.

Another reason for increasing antibiotic resistance in bacteria is their uses in diseases in which they have no result.  For example antibiotics are not effective against infections caused by viruses.

Resistance to antibiotics poses a serious and growing problem, because some infectious diseases are becoming more difficult to treat. Some of the resistant bacteria can be treated with more powerful antibiotics, but there are some infections that do not eliminate even with new antibiotics.

 

Question 10: What are vaccines? Explain the mode of action of vaccines?

Answer: Vaccines: word vaccine from Latin vaccinus meaning of or from cow. A vaccine is a material containing weakened or killed pathogens and is used to produce immunity to a disease by stimulating the production of antibodies.

In 1796, a British physician, Edward Jenner, infected a young boy with cowpox, by injecting pus cells. After the boy had recovered from cowpox, Jenner injected the pus cells from a smallpox patient into him. The boy did not get smallpox.

So it became clear that intentional infection with cowpox protected people from smallpox. This method was named “vaccination” and the substance used to vaccinate was called a “vaccine”.

 

Method of production or preparation of vaccines: It is produced by making a suspension of killed or harmless (weak) microorganisms or their products or derivatives.

 

The Mode of Action of Vaccines: Pathogens contain special proteins called “antigens”. When pathogens enter the body (blood) of host, these proteins stimulate the immune response in host i.e. synthesis of “antibodies”. Antibodies bind to pathogens and destroy them and remember them. Whenever in future microorganisms of that disease invade the body, the antibodies capture them and destroy them before they spread infections. These antibodies are produced by a type of white blood cells called B-Lymphocytes.

Methods of administration: Most common methods of administering vaccines are by injection, but some are given by mouth or nasal spray.

 

For your information: Children are required to be vaccinated before attending school. The vaccination of children has resulted in marked decrease of many once-common diseases including whooping cough, polio, smallpox and others.

Some vaccines do not provide lifetime immunity. For example, tetanus vaccines are only effective for a limited period of time. In such cases, booster shots are necessary to maintain continuous protection.

Any disease causing organism is called pathogen.

 

UNDERSTANDING THE CONCEPT

  1. What are the sources of drugs? Give examples.

Answer: Please see answer of question no.4.

 

  1. Write a note on sedatives, narcotics and hallucinogens.

Answer: Please see answer of question no. 6.

 

  1. Describe the main groups of antibiotics.

Answer: Please see answer of question no. 8.

 

  1. Write a note on resistance against antibiotics.

Answer: Please see answer of question no. 9.

 

  1. Describe the mode of action of vaccines.

Answer: Please see answer of question no. 10.

 

SHORT QUESTIONS

 

  1. Define pharmacology and distinguish it from pharmacy.

Answer:  Pharmacy deals with dispensing of drugs while pharmacology deals to the reactions related to the use of medicines in the body of living (specially human being).

 

  1. Differentiate between medicinal drug and addictive drug.

Answer:

Medicinal drug or pharmaceutical drug or Medicine: Any chemical substance used in diagnosis, cure, treatment or prevention of diseases is called Medicine.

Addictive drug: Drugs which the person becomes dependent or addicted are called addictive drugs. The uncontrollable desire for drug is called drug addiction.

 

  1. Differentiate between analgesic and antibiotic.

Answer: Analgesics are used for pain relief while antibiotics are medicines used for bacterial infections means they kills or slows down the growth of bacteria.

 

  1. What is marijuana? To which category of addictive drugs, it belongs?

Answer: Marijuana: Marijuana is one of the most commonly used drugs in the world, following only caffeine, nicotine, and alcoholic beverages in popularity.

Marijuana is a hallucinogen which is smoked. It is obtained from the flowers, stems and leaves of marijuana plants (Canabis sativa and Canabis indica).

  1. Differentiate between narcotics and hallucinogens.

Answer:  Hallucinogens: Hallucinogens are the drugs that cause changes in perception, thoughts, emotions and consciousness. Examples: (1) Mescaline obtained from cactus. (2) Psilocin obtained from magic mushroom (Psilocybian). Other examples are Datura, Cannabis, Salvia divinorum, Morning glory, Peyote (a Cactus), etc.

Effects of Hallucinogens: Physiologically hallocinogens effects on sympathetic nervous system, causing: (a) Constriction of the some arteries. (b) Rise in blood pressure. (C) Dilation of pupils.

 

Narcotics: Narcotics are strong painkillers, induce sleep and cause dullness to senses. These drugs act on CNS, so these are often used with less potent pain killers (paracetamol or aspirin).

Uses: These are often used to relieve pain in chronic diseases such as cancer. These are also used to relieve pain after operation.

 

Examples of narcotics: Examples of narcotics are morphine and codeine. These are obtained from opium.

 

THE TERMS TO KNOW

 

Addictive drug: Addictive drug: Drugs which the person becomes dependent or addicted are called addictive drugs. The uncontrollable desire for drug is called drug addiction.

Analgesic: The medicines that reduce pain are called analgesics.

Antibiotic: The medicines which inhibit or kill bacteria.

Aspirin: Acetaminophen; A pain-killer medicine.

Bactericidal: The antibiotics that work by killing bacteria.

Bacteriostatic: The antibiotics that work by stopping bacteria multiplying or stop bacterial growth.

Cardiotonic: Medicines that give strength to heart muscles.

Cephalosporin: A group of antibiotics; interfere with synthesis of the bacterial cell wall.

Hallucinogen: Drug that causes changes in perception, thought, emotion and consciousness.

Heroin: A commonly abused narcotic; derived from morphine; affects the central nervous system and causes drowsiness, disorientation, hypotension etc.

Marijuana: A hallucinogen and addictive drug; obtained from the flowers, stems, and leaves of the marijuana plant.

Medicinal drug or pharmaceutical drug or Medicine: Any chemical substance used in diagnosis, cure, treatment or prevention of diseases is called Medicine.

Morphine: A commonly used narcotic obtained from the juice of opium that act directly on CNS and relieve pain.

Narcotics: Strong painkiller drugs; also used as addictive drugs; commonly abused narcotics include heroin, morphine, methadone etc.

Pharmacology: Pharmacology is the combination of two Greek words. Pharmakon means drug and logy means to study or to discuss. Pharmacology is the study of drug composition, properties and medical applications.  OR Pharmacology is the study of action of drug.

Pharmacy: Pharmacy is the study of preparation and dispensing of drugs.

Sedatives: Types of drugs that interact with the central nervous system to depress its activities; make a person calm or drowsy.

Sulfonamide: Sulpha drugs: Synthetic antibiotics that contain the sulfonamide group; bacteriostatic in action.

Gout: A type of arthritis characterized by uric acid crystals in the moveable joints.

Tetracycline: Broad-spectrum bacteriostatic antibiotics; inhibit bacterial protein synthesis.

Vaccine: The material used to produce immunity to a disease by stimulating the production of antibodies.

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