CHAPTER 7 - HUMAN HEALTH AND DISEASE

 

Health

Health is defined as a state of complete physical, mental and social well-being.

Factors Affecting Health

  • Health is affected by –
    1. Genetic disorders– deficiencies with which a child is born and deficiencies/defects which the child inherits from parents from birth;
    2. Infections
    3. Life style including food and water we take, rest and exercise we give to our bodies, habits that we have or lack etc.

Disease

  • When the functioning of one or more organs or systems of the body is adversely affected, this state is called disease.
  • Types of disease -
    • Infectious
    • Non-infectious

Pathogens

  1. A wide range of organisms belonging to bacteria, viruses, fungi, protozoans, helminths, etc., causing diseases in human are called pathogens.
  2. Sometimes, pathogens are carried on/in other's organisms body, these pathogens transmitting agents/organisms are called vectors.

Common Disease in Humans

Typhoid

  1. Salmonella typhi is a pathogenic bacterium which causes typhoid fever in human beings.
  2. These pathogens generally enter the small intestine through food and water contaminated with them and migrate to other organs through blood.
  3. Symptoms -
    • Sustained high fever (39° to 40°C)
    • Weakness
    • Stomach pain
    • Constipation
    • Headache and
    • Loss of appetite are some of the common of this disease.
  4. Intestinal perforation and death may occur in severe cases.
  5. Typhoid fever could be confirmed by Widal test.

Pneumonia

  1. Bacteria like Streptococcus pneumoniae and Haemophilus influenzae are responsible for the disease pneumonia in humans which infects the alveoli (air filled sacs) of the lungs.
  2. As a result of the infection, the alveoli get filled with fluid leading to severe problems in respiration.
  3. The symptoms of pneumonia include fever, chills, cough and headache.
  4. In severe cases, the lips and finger nails may turn gray to bluish in colour.
  5. A healthy person acquires the infection by inhaling the droplets/aerosols released by an infected person or even by sharing glasses and utensils with an infected person.

Common cold

  1. Rhino viruses cause one of the most infectious human ailments – the common cold.
  2. They infect the nose and respiratory passage but not the lungs.
  3. The common cold is characterised by nasal congestion and discharge, sore throat, hoarseness, cough, headache, tiredness, etc., which usually last for 3-7 days.
  4. Droplets resulting from cough or sneezes of an infected person are either inhaled directly or transmitted through contaminated objects such as pens, books, cups, doorknobs, computer keyboard or mouse, etc., and cause infection in a healthy person.

Malaria

  1. Plasmodium, a tiny protozoan is responsible for this disease.
  2. Different species of Plasmodium (P. vivax, P. malaria and P. falciparum) are responsible for different types of malaria.
  3. Of these, malignant malaria caused by Plasmodium falciparum is the most serious one and can even be fatal.

Life cycle of Plasmodium

  1. Plasmodium enters the human body as sporozoites (infectious form) through the bite of infected female Anopheles mosquito.
  2. The parasites initially multiply within the liver cells and then attack the red blood cells (RBCs) resulting in their rupture.
  3. The rupture of RBCs is associated with release of a toxic substance, haemozoin, which is responsible for the chill and high fever recurring every three to four days.
  4. When a female Anopheles mosquito bites an infected person, these parasites enter the mosquito’s body and undergo further development.
  5. The parasites multiply within them to form sporozoites that are stored in their salivary glands.
  6. When these mosquitoes bite a human, the sporozoites are introduced into his/her body, thereby initiating the events mentioned above.
  7. It is interesting to note that the malarial parasite requires two hosts – human and mosquitoes – to complete its life cycle; the female Anopheles mosquito is the vector (transmitting agent) too.

Amoebiasis (amoebic dysentery)

  1. Entamoeba histolytica is a protozoan parasite in the large intestine of human which causes amoebiasis (amoebic dysentery).
  2. Symptoms of this disease include constipation, abdominal pain and cramps, stools with excess mucous and blood clots.
  3. Houseflies act as mechanical carriers and serve to transmit the parasite from faeces of infected person to food and food products, thereby contaminating them.
  4. Drinking water and food contaminated by the faecal matter are the main source of infection.

Ascariasis

  1. Ascaris, the common round worm and Wuchereria, the filarial worm, are some of the helminths which are known to be pathogenic to man.
  2. Ascaris, an intestinal parasite causes ascariasis.
  3. Symptoms of these disease include internal bleeding, muscular pain, fever, anemia and blockage of the intestinal passage.
  4. The eggs of the parasite are excreted along with the faeces of infected persons which contaminate soil, water, plants, etc.
  5. A healthy person acquires this infection through contaminated water, vegetables, fruits, etc.

Elephantiasis or Filariasis

  1. Wuchereria (W. bancrofti and W. malayi), the filarial worms cause a slowly developing chronic inflammation of the organs in which they live for many years, usually the lymphatic vessels of the lower limbs and the disease is called elephantiasis or filariasis.
  2. The genital organs are also often affected, resulting in gross deformities.
  3. The pathogens are transmitted to a healthy person through the bite by the female mosquito vectors.

Ringworms

  1. Many fungi belonging to the genera Microsporum, T richophyton and Epidermophyton are responsible for ringworms which is one of the most common infectious diseases in man.
  2. Appearance of dry, scaly lesions on various parts of the body such as skin, nails and scalp are the main symptoms of the disease.
  3. These lesions are accompanied by intense itching.
  4. Heat and moisture help these fungi to grow, which makes them thrive in skin folds such as those in the groin or between the toes.
  5. Ringworms are generally acquired from soil or by using towels, clothes or even the comb of infected individuals.

Maintenance of hygiene

  • Maintenance of personal and public hygiene is very important for prevention and control of many infectious diseases.
  • Personal hygiene -
    • Measures for personal hygiene include
      • keeping the body clean;
      • consumption of clean drinking water, food, vegetables, fruits, etc.
  • Public hygiene -
    • It includes
      • proper disposal of waste and excreta;
      • periodic cleaning and disinfection of water reservoirs, pools, cesspools and tanks and
      • observing standard practices of hygiene in public catering.
  • These measures are particularly essential where the infectious agents are transmitted through food and water such as typhoid, amoebiasis and ascariasis.
  • In cases of air-borne diseases such as pneumonia and common cold, avoid close contact with the infected persons or their belongings.
  • For diseases such as malaria and filariasis that are transmitted through insect vectors, the most important measure is to control or eliminate the vectors and their breeding places.
    • This can be achieved by
      • avoiding stagnation of water in and around residential areas,
      • regular cleaning of household coolers,
      • use of mosquito nets,
      • introducing fishes like Gambusia in ponds that feed on mosquito larvae,
      • spraying of insecticides in ditches, drainage areas and swamps, etc.
      • doors and windows should be provided with wire mesh to prevent the entry of mosquitoes.
    • Such precautions have become more important especially in the light of recent widespread incidences of the vector-borne (Aedes mosquitoes) diseases like dengue and chikungunya in many parts of India.
  • The advancements made in biological science have armed us to effectively deal with many infectious diseases.
    • The use of vaccines and immunisation programmes have enabled us to completely eradicate a deadly disease like smallpox.
    • A large number of other infectious diseases like polio, diphtheria, pneumonia and tetanus have been controlled to a large extent by the use of vaccines.
    • Biotechnology is at the verge of making available newer and safer vaccines.
    • Discovery of antibiotics and various other drugs has also enabled us to effectively treat infectious diseases

Immunity

  • The ability of the host to fight the disease-causing organisms, conferred by the immune system is called immunity.
  • Types -
    • Immunity is of two types -
      • Innate immunity
      • Acquired immunity

Innate Immunity

  • Innate immunity is non-specific type of defence, that is present at the time of birth.

Types of barriers

  • This is accomplished by providing different types of barriers to the entry of the foreign agents into our body.
  • Innate immunity consist of four types of barriers. These are -
    1. Physical barriers :
      • Skin on our body is the main barrier which prevents entry of the micro-organisms.
      • Mucus coating of the epithelium lining the respiratory, gastrointestinal and urogenital tracts also help in trapping microbes entering our body.
    2. Physiological barriers :
      • Acid in the stomach, saliva in the mouth, tears from eyes–all prevent microbial growth.
    3. Cellular barriers :
      • Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes.
    4. Cytokine barriers :
      • Virus-infected cells secrete proteins called interferons (IFN) which protect non-infected cells from further viral infection.

Acquired Immunity

  • Acquired immunity is pathogen-specific type of defence, that is achieved in response of attack of microbes.
  • It has two types of response -
    • Primary Response -
      • When our body encounters a pathogen for the first time it produces a response called primary response which is of low intensity.
    • Secondary Response -
      • Subsequent encounter with the same pathogen elicits a highly intensified secondary or anamnestic response.
    • The primary and secondary immune responses are carried out with the help of two special types of lymphocytes present in our blood, i.e.,
      • B-lymphocytes
      • T-lymphocytes

Types of Acquired Immunity

  • There are two types of acquired immunity -
    • humoral immunity
    • cell-mediated immunity

Humoral Immunity

  • In this, antibodies are found in the blood to fight with pathogens.
    • The B-lymphocytes produce an army of proteins in response to pathogens into our blood to fight with them. These proteins are called antibodies.
    • The T-cells themselves do not secrete antibodies but help B cells to produce them.
  • Structure of an antibody molecule -
    • Each antibody molecule has four peptide chains, two small called light chains and two longer called heavy chains. Hence, an antibody is represented as H2L2.
    • Different types of antibodies are produced in our body. IgA, IgM, IgE, IgG are some of them.

Cell-Mediated Immunity

  • T-lymphocytes mediate Cell-Mediated Immunity (CMI).
  • Cell-Mediated Immune response is responsible for the graft rejection.

Active Immunity

  • When a host is exposed to antigens, which may be in the form of living or dead microbes or other proteins, antibodies are produced in the host body. This type of immunity is called active immunity.

Passive Immunity

  • When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity.
  • e.g. The yellowish fluid colostrum

Vaccination

  • Introduction of a preparation of antigenic proteins of pathogen or inactivated/weakened pathogen (vaccine) into the body is called vaccination.

Passive immunisation

  • When the injection of preformed antibodies or antitoxin (a preparation containing antibodies to the toxin) against a disease is given to the patients. This type of immunisation is called passive immunisation.

Allergy

  • The exaggerated response of the immune system to certain antigens present in the environment is called allergy.
  • Allergy is due to the release of chemicals like histamine and serotonin from the mast cells.
  • Symptoms - sneezing, watery eyes, running nose and difficulty in breathing.

Allergens

  • The substances to which such an immune response is produced are called allergens.
  • Common examples of allergens are mites in dust, pollens, animal dander, etc.

Auto Immunity

  • Due to genetic and other unknown reasons, the body attacks self-cells which results in damage to the body and is called auto-immune disease. e.g. Rheumatoid arthritis

Immune System in the Body

  • Our immune system is unique in the sense that it recognises foreign antigens, responds to these and remembers them.
  • The immune system also plays an important role in allergic reactions, auto-immune diseases and organ transplantation.

Lymphoid organs

  1. These are the organs where origin and/or maturation and proliferation of lymphocytes occur.
  2. The primary lymphoid organs are bone marrow and thymus.
  3. Immature lymphocytes differentiate into antigen-sensitive lymphocytes.
  4. After maturation the lymphocytes migrate to secondary lymphoid organs like spleen, lymph nodes, tonsils, Peyer’s patches of small intestine and appendix.
  5. The secondary lymphoid organs provide the sites for interaction of lymphocytes with the antigen, which then proliferate to become effector cells.
  6. Bone marrow - It is the main lymphoid organ where all blood cells including lymphocytes are produced.
  7. Thymus -
    • It is a lobed organ located near the heart and beneath the breastbone.
    • The thymus is quite large at the time of birth but keeps reducing in size with age and by the time puberty is attained it reduces to a very small size.
  8. Both bone- marrow and thymus provide micro-environments for the development and maturation of T-lymphocytes.
  9. Spleen -
    • It is a large bean- shaped organ.
    • It mainly contains lymphocytes and phagocytes.
    • It acts as a filter of the blood by trapping blood-borne micro-organisms.
    • Spleen also has a large reservoir of erythrocytes.
  10. Lymph nodes -
    • They are small solid structures located at different points along the lymphatic system.
    • Lymph nodes serve to trap the micro-organisms or other antigens, which happen to get into the lymph and tissue fluid.
    • Antigens trapped in the lymph nodes are responsible for the activation of lymphocytes present there and cause the immune response.
    • There is lymphoid tissue also located within the lining of the major tracts (respiratory, digestive and urogenital tracts) called mucosa-associated lymphoid tissue (MALT).
    • It constitutes about 50% of the lymphoid tissue in human body.

AIDS

  1. The word AIDS stands for Acquired Immuno Deficiency Syndrome.
  2. This means deficiency of immune system, acquired during the lifetime of an individual indicating that it is not a congenital disease.
  3. ‘Syndrome’ means a group of symptoms.
  4. AIDS was first reported in 1981 and in the last twenty-five years or so, it has spread all over the world killing more than 25 million persons.
  5. Cause -
    • AIDS is caused by the Human Immuno deficiency Virus (HIV), a member of a group of viruses called retrovirus, which have an envelope enclosing the RNA genome.
  6. Transmission of HIV-infection - It generally occurs by
    • (a) sexual contact with infected person,
    • (b) by transfusion of contaminated blood and blood products,
    • (c) by sharing infected needles as in the case of intravenous drug abusers and
    • (d) from infected mother to her child through placenta.
  7. So, people who are at high risk of getting this infection includes - individuals who have multiple sexual partners, drug addicts who take drugs intravenously, individuals who require repeated blood transfusions and children born to an HIV infected mother.
  8. There is always a time-lag between the infection and appearance of AIDS symptoms. This period may vary from a few months to many years (usually 5-10 years).
  9. Symptoms -
    • During this period, the person suffers from bouts of fever, diarrhoea and weight loss.
    • Due to decrease in the number of helper T lymphocytes, the person starts suffering from infections that could have been otherwise overcome such as those due to bacteria especially Mycobacterium, viruses, fungi and even parasites like Toxoplasma.
    • The patient becomes so immuno-deficient that he/she is unable to protect himself/herself against these infections.
  10. ELISA -
    • A widely used diagnostic test for AIDS is enzyme linked immuno-sorbent assay (ELISA).
    • Treatment of AIDS with anti-retroviral drugs is only partially effective.
    • They can only prolong the life of the patient but cannot prevent death, which is inevitable.

Replication of retrovirus

  1. After getting into the body of the person, the virus enters into macrophages where RNA genome of the virus replicates to form viral DNA with the help of the enzyme reverse transcriptase.
  2. This viral DNA gets incorporated into host cell’s DNA and directs the infected cells to produce virus particles.
  3. The macrophages continue to produce virus and in this way acts like a HIV factory.
  4. Simultaneously, HIV enters into helper T-lymphocytes (TH), replicates and produce progeny viruses.
  5. The progeny viruses released in the blood attack other helper T-lymphocytes.
  6. This is repeated leading to a progressive decrease in the number of helper T-lymphocytes in the body of the infected person.

Prevention of AIDS

  1. As AIDS has no cure, prevention is the best option.
  2. In our country the National AIDS Control Organisation (NACO) and other non-governmental organisation (NGOs) are doing a lot to educate people about AIDS.
  3. WHO has started a number of programmes to prevent the spreading of HIV infection.
  4. Making blood (from blood banks) safe from HIV, ensuring the use of only disposable needles and syringes in public and private hospitals and clinics, free distribution of condoms, controlling drug abuse, advocating safe sex and promoting regular check-ups for HIV in susceptible populations, are some such steps taken up.

Cancer

  1. In cancer cells, there is breakdown of regulatory mechanisms of cell growth and differentiation.
  2. Cancerous cells continue to divide giving rise to masses of cells called tumors.
  3. Types -
    • Tumors are of two types -
      1. Benign tumors -
        • Benign tumors normally remain confined to their original location and do not spread to other parts of the body and cause little damage.
      2. Malignant tumors -
        • A mass of proliferating cells (called neoplastic or tumor cells) grow very rapidly, invading and damaging the surrounding normal tissues.
  4. Metastasis -
    • When cells from tumors reach distant sites through blood, and wherever they get lodged in the body, they start a new tumor there. This property called metastasis.

Causes of cancer

  1. Carcinogens -
    • Transformation of normal cells into cancerous neoplastic cells may be induced by physical, chemical or biological agents. These agents are called carcinogens.
    • Ionising radiations like X-rays and gamma rays and non-ionizing radiations like UV cause DNA damage leading to neoplastic transformation.
    • The chemical carcinogens present in tobacco smoke have been identified as a major cause of lung cancer.
  2. Oncogenes -
    • Viral oncogenes -
      • Cancer causing viruses called oncogenic viruses have genes called viral oncogenes.
    • Cellular oncogenes (c-onc) or proto oncogenes -
      • Several genes called cellular oncogenes (c-onc) or proto oncogenes get activated under certain conditions, could lead to oncogenic transformation of the cells.

Cancer detection and diagnosis

  • Cancer detection is done as -
    1. Biopsy and histopathological studies -
      • In biopsy, a piece of the suspected tissue cut into thin sections is stained and examined under microscope (histopathological studies) by a pathologist.
    2. Blood and bone marrow tests -
      • This is done for increased cell counts in the case of leukemias.
    3. Techniques -
      • Radiography technique like X-rays, CT (computed tomography) and MRI (magnetic resonance imaging) are very useful to detect cancers of the internal organs.
      • Computed tomography uses X-rays to generate a three-dimensional image of the internals of an object.
      • MRI uses strong magnetic fields and non-ionising radiations to accurately detect pathological and physiological changes in the living tissue.
    4. Antibodies -
      • Antibodies against cancer -specific antigens are also used for detection of certain cancers.
    5. Techniques of molecular biology -
      • This can be applied to detect genes in individuals with inherited susceptibility to certain cancers.
      • Identification of such genes, which predispose an individual to certain cancers, may be very helpful in prevention of cancers.
      • Such individuals may be advised to avoid exposure to particular carcinogens to which they are susceptible (e.g., tobacco smoke in case of lung cancer).

Treatment of cancer

  • The common approaches for treatment of cancer are surgery, radiation therapy and immunotherapy.
  • Radiotherapy -
    • In radiotherapy, tumor cells are irradiated lethally, taking proper care of the normal tissues surrounding the tumor mass.
  • Chemotherapeutic drugs -
    • Several chemotherapeutic drugs are used to kill cancerous cells.
    • Some of these are specific for particular tumors.
    • Majority of drugs have side effects like hair loss, anemia, etc.
  • Combined approaches -
    • Most cancers are treated by combination of surgery, radiotherapy and chemotherapy.
    • Tumor cells have been shown to avoid detection and destruction by immune system.
    • Therefore, the patients are given substances called biological response modifiers such as α-interferon (α-IFN) which activates their immune system and helps in destroying the tumor.

Drugs

  • Drugs have medicinal properties but their excessive use (abuse) could result in many harmful effects.
  • The drugs, which are commonly abused are opioids, cannabinoids and coca alkaloids.
  • These are obtained from flowering plants and fungi.
  • These may be -
    • Opioids
    • Cannabinoids

Opioids

  1. They are the drugs, which bind to specific opioid receptors present in our central nervous system and gastrointestinal tract.
  2. Heroin (or smack) is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound.
  3. This is obtained by acetylation of morphine, which is extracted from the latex of poppy plant Papaver somniferum.
  4. Generally taken by snorting and injection, heroin is a depressant and slows down body functions.

Cannabinoids

  1. Cannabinoids are a group of chemicals, which interact with cannabinoid receptors present principally in the brain.
  2. Natural cannabinoids are obtained from the inflorescences of the plant Cannabis sativa.
  3. The flower tops, leaves and the resin of cannabis plant are used in various combinations to produce marijuana, hashish, charas and ganja.
  4. Generally taken by inhalation and oral ingestion, these are known for their effects on cardiovascular system of the body.

Coca alkaloid or cocaine

  1. Coca alkaloid or cocaine is obtained from coca plant Erythroxylum coca, native to South America.
  2. It interferes with the transport of the neuro-transmitter dopamine.
  3. Cocaine, commonly called coke or crack is usually snorted.
  4. It has a potent stimulating action on central nervous system, producing a sense of euphoria and increased energy.
  5. Excessive dosage of cocaine causes hallucinations.
  6. Other well-known plants with hallucinogenic properties are Atropa belladona and Datura.
  7. These days cannabinoids are also being abused by some sportspersons.

Morphine

  • Morphine is a very effective sedative and painkiller.
  • It is very useful in patients who have undergone surgery.

Tobacco

  • It is smoked, chewed or used as a snuff.
  • Tobacco contains a large number of chemical substances including nicotine, an alkaloid.
  • Nicotine stimulates adrenal gland to release adrenaline and nor-adrenaline into blood circulation, both of which raise blood pressure and increase heart rate.
  • Smoking is associated with increased incidence of cancers of lung, urinary bladder and throat, bronchitis, emphysema, coronary heart disease, gastric ulcer, etc.
  • Tobacco chewing is associated with increased risk of cancer of the oral cavity.
  • Smoking increases carbon monoxide (CO) content in blood and reduces the concentration of haembound oxygen. This causes oxygen deficiency in the body.

Adolescence and Drug/Alcohol Abuse

  • Adolescence is a bridge linking childhood and adulthood.
  • The period between 12-20 years of age is termed as adolescence period.
  • Adolescence means both ‘a period’ and ‘a process’ during which a child becomes mature in terms of his/her attitudes and beliefs for effective participation in society.
  • Adolescence is accompanied by several biological and behavioural changes.
    • Adolescence, thus is a very vulnerable phase of mental and psychological development of an individual.
  • Curiosity, need for adventure and excitement and experimentation, divert youngsters towards drug and alcohol use.
  • Other factors that have been seen to be associated with drug and alcohol abuse among adolescents are unstable or unsupportive family structures and peer pressure.

Drug Addiction and Dependence

Addiction

  • Addiction is a psychological attachment to certain effects – such as euphoria and a temporary feeling of well-being – associated with drugs and alcohol.
  • These drive people to take them even when these are not needed, or even when their use becomes self-destructive.

Dependence

  • Dependence is the tendency of the body to manifest a characteristic and unpleasant withdrawal syndrome if regular dose of drugs/alcohol is abruptly discontinued.
  • This is characterised by anxiety, shakiness, nausea and sweating, which may be relieved when use is resumed again.

Effects of Drug/Alcohol Abuse

  • reckless behaviour, vandalism and violence
  • coma and death due to respiratory failure, heart failure or cerebral hemorrhage
  • drop in academic performance, unexplained absence from school/college, lack of interest in personal hygiene, withdrawal, isolation, depression, fatigue, aggressive and rebellious behaviour, deteriorating relationships with family and friends, loss of interest in hobbies, change in sleeping and eating habits, fluctuations in weight, appetite, etc.
  • mental and financial distress
  • infections like AIDS and Hepatitis B
  • The chronic use of drugs and alcohol damages nervous system and liver (cirrhosis)
  • side-effects in females
    • masculinisation (features like males), increased aggressiveness, mood swings, depression, abnormal menstrual cycles, excessive hair growth on the face and body, enlargement of clitoris, deepening of voice.
  • side-effects in males
    • acne, increased aggressiveness, mood swings, depression, reduction of size of the testicles, decreased sperm production, potential for kidney and liver dysfunction, breast enlargement, premature baldness, enlargement of the prostate gland
  • stunted growth

Prevention and Control

  • Useful measures for prevention and control of alcohol and drugs abuse among adolescents
    • Avoid undue peer pressure -
      • Every child has his/her own choice and personality, which should be respected and nurtured.
      • A child should not be pushed unduly to perform beyond his/her threshold limits; be it studies, sports or other activities.
    • Education and counselling -
      • Educating and counselling him/her to face problems and stresses, and to accept disappointments and failures as a part of life.
      • It would also be worthwhile to channelise the child’s energy into healthy pursuits like sports, reading, music, yoga and other extracurricular activities.
    • Seeking help from parents and peers -
      • Help from parents and peers should be sought immediately so that they can guide appropriately. Help may even be sought from close and trusted friends.
      • Besides getting proper advise to sort out their problems, this would help young to vent their feelings of anxiety and guilt.
    • Looking for danger signs -
      • Alert parents and teachers need to look for and identify the danger signs.
      • Even friends, if they find someone using drugs or alcohol, should not hesitate to bring this to the notice of parents or teacher in the best interests of the person concerned.
      • Appropriate measures would then be required to diagnose the malady and the underlying causes. This would help in initiating proper remedial steps or treatment.
    • Seeking professional and medical help -
      • A lot of help is available in the form of highly qualified psychologists, psychiatrists, and de-addiction and rehabilitation programmes to help individuals who have unfortunately got in the quagmire of drug/alcohol abuse.
      • With such help, the affected individual with sufficient efforts and will power, can get rid of the problem completely and lead a perfectly normal and healthy life.

One Mark Questions

Q1. What is abuse?

Ans. Misuse and overuse is abuse in biology.

Q2. What is addiction?

Ans. Addiction is a psychological attachment to certain effects – such as euphoria and a temporary feeling of well-being – associated with drugs and alcohol.

Q3. What is dependence?

Ans. Dependence is the tendency of the body to manifest a characteristic and unpleasant withdrawal syndrome if regular dose of drugs/alcohol is abruptly discontinued.

CHAPTER 6 – EVOLUTION

CHAPTER 8 – MICROBES IN HUMAN WELFARE

Comments

Post a Comment

Popular posts from this blog

CHAPTER 6 - EVOLUTION

  Evolutionary Biology is the biology in which we study about history of life forms on earth. Various theory has been proposed about origin of life forms. Theories about origin of life forms Various theories has been given in support how first life appear on earth. They are as below - Some scientists believe that it came from outside. Early Greek thinkers thought units of life called spores were transferred to different planets including earth. ‘Panspermia’ is still a favourite idea for some astronomers. For a long time it was also believed that life came out of decaying and rotting matter like straw, mud, etc. This was the theory of spontaneous generation . Louis Pasteur by careful experimentation demonstrated that life comes only from pre-existing life. He showed that in pre-sterilised flasks, life did not come from killed yeast while in another flask open to air, new living organisms arose from ‘killed yeast’. Oparin of Russia and Haldane of England pro...
Read more

Rest work

   Population Interactions For any species, the minimal requirement is one more species on which it can feed. Even a plant species, which makes its own food, cannot survive alone; it needs soil microbes to break down the organic matter in soil and return the inorganic nutrients for absorption. In nature, animals, plants and microbes interact in various ways to form a biological community. Interspecific interactions arise from the interaction of populations of two different species. They could be beneficial, detrimental or neutral (neither harm nor benefit) to one of the species or both. Assigning a ‘+’ sign for beneficial interaction, ‘-’ sign for detrimental and 0 for neutral interaction, look at all the possible outcomes of interspecific interactions. Species A Species B Name of Interaction + + Mutualism - - Competition + - Predation + - Parasitism + 0 Commensalism - 0 Amensalism Both the species benefit in mutualism and both lose in competition in their interactions with ea...
Read more