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Course: Ncert -Class 12 - Biology:Unit VIII - Bi...
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Detailed Notes -2-Chapter 7 Human Health and Disease

7.3 AIDS

  1. Definition and Introduction:

    • AIDS stands for Acquired Immuno Deficiency Syndrome, indicating a deficiency in the immune system acquired during an individual’s lifetime.
    • It was first reported in 1981 and has since spread globally, resulting in the deaths of over 25 million people.
  2. Causative Agent:

    • AIDS is caused by the Human Immunodeficiency Virus (HIV), a retrovirus with an RNA genome enclosed in an envelope.
    • HIV transmission occurs through sexual contact, blood transfusion, sharing contaminated needles, and from infected mother to child during childbirth.
  3. High-Risk Groups:

    • Individuals at high risk of HIV infection include those with multiple sexual partners, intravenous drug users, recipients of repeated blood transfusions, and children born to HIV-infected mothers.
  4. Pathogenesis:

    • HIV enters macrophages and helper T-lymphocytes, replicating within these cells and leading to a progressive decrease in helper T-lymphocyte count.
    • Decreased helper T-lymphocytes result in immunodeficiency, making the individual susceptible to opportunistic infections.
  5. Symptoms and Diagnosis:

    • Symptoms of AIDS include fever, diarrhea, weight loss, and susceptibility to various infections.
    • Diagnosis often involves enzyme-linked immunosorbent assay (ELISA) testing.
  6. Treatment and Prevention:

    • Treatment with antiretroviral drugs can prolong life but cannot cure AIDS.
    • Prevention measures include safe sex practices, avoiding needle sharing, ensuring safe blood transfusions, and promoting awareness and education about HIV/AIDS.
    • Organizations like the National AIDS Control Organisation (NACO), NGOs, and the World Health Organization (WHO) are actively involved in prevention efforts.
  7. Societal Impact and Stigma:

    • HIV/AIDS-infected individuals should not be stigmatized; they need support and understanding from society.
    • Societal recognition and collective action are crucial in addressing the spread of HIV/AIDS.

7.4 CANCER

  1. Definition and Overview:

    • Cancer is a major cause of death globally, characterized by uncontrolled cell growth and proliferation.
    • Tumors, masses of cells, can be benign (localized) or malignant (invasive).
    • Malignant tumors spread to other parts of the body through a process called metastasis.
  2. Causes of Cancer:

    • Cancer can be induced by physical (radiation), chemical (carcinogens), or biological (oncogenic viruses) agents.
    • Carcinogens cause DNA damage, leading to neoplastic transformation.
    • Genetic factors, including oncogenes and proto-oncogenes, play a role in cancer development.
  3. Detection and Diagnosis:

    • Early detection is crucial for successful treatment.
    • Biopsy, histopathological studies, and blood/bone marrow tests are used for diagnosis.
    • Imaging techniques like radiography, CT scans, and MRI help detect internal organ cancers.
    • Molecular biology techniques can identify genes associated with inherited susceptibility to cancer.
  4. Treatment:

    • Common treatment approaches include surgery, radiation therapy, chemotherapy, and immunotherapy.
    • Surgery aims to remove tumors, while radiation therapy targets tumor cells with radiation.
    • Chemotherapy drugs kill cancer cells but can have side effects.
    • Immunotherapy uses substances to activate the immune system to target and destroy tumors.

7.5 DRUGS AND ALCOHOL ABUSE

  1. Opioids:

    • Derived from opium poppy.
    • Examples include heroin (diacetylmorphine) and morphine.
    • Bind to opioid receptors in the central nervous system and gastrointestinal tract.
    • Heroin is a depressant, slowing down bodily functions.
  2. Cannabinoids:

    • Found in Cannabis sativa.
    • Interact with receptors in the brain, affecting the cardiovascular system.
    • Products include marijuana, hashish, charas, and ganja.
    • Inhalation and oral ingestion are common methods of consumption.
  3. Coca Alkaloids:

    • Derived from the coca plant (Erythroxylum coca).
    • Cocaine interferes with dopamine transport, stimulating the central nervous system.
    • Produces euphoria and increased energy when snorted.
  4. Other Drugs:

    • Include barbiturates, amphetamines, benzodiazepines, etc.
    • Used for mental illnesses but often abused.
    • Morphine is a sedative and painkiller, despite its medical benefits.
  5. Hallucinogenic Plants:

    • Atropa belladonna and Datura are examples.
    • Used in folk medicine and rituals for centuries.
    • Can cause hallucinations and altered states of consciousness.
  6. Tobacco:

    • Contains nicotine, stimulating adrenaline release.
    • Increases risk of various diseases, including cancer, bronchitis, and heart disease.
    • Smoking and chewing tobacco are associated with health risks.
    • Despite warnings, smoking remains prevalent in society.

7.5.1 Adolescence and Drug/Alcohol Abuse

  1. Adolescence Definition and Characteristics:

    • Adolescence is both a period and a process where a child matures in attitudes and beliefs.
    • It typically occurs between the ages of 12 to 18, serving as a bridge between childhood and adulthood.
    • This phase is marked by various biological and behavioral changes, making it a vulnerable period for mental and psychological development.
  2. Causes of Drug/Alcohol Abuse in Adolescents:

    • Curiosity, need for adventure, and a desire for excitement are common motivators.
    • Experimentation often stems from natural curiosity but may be influenced by perceived benefits of substance use.
    • Stress, particularly from academic pressures, can drive adolescents to try alcohol and drugs as coping mechanisms.
    • Social influences, such as the perception that substance use is “cool” or progressive, play a significant role, fueled by media portrayal in television, movies, and the internet.
    • Family dynamics, including unstable or unsupportive structures, can contribute to substance abuse, as can peer pressure.

7.5.2 Addiction and Dependence

  1. Addiction:

    • Addiction is a psychological attachment to the effects of drugs and alcohol, such as euphoria and temporary well-being.
    • People may continue to use these substances even when they are not needed or when their use becomes self-destructive.
    • With repeated use, the body develops tolerance, requiring higher doses to achieve the same effects, leading to increased intake and addiction.
    • Even a single use of drugs or alcohol can lead to addiction, emphasizing their addictive potential.
    • Addiction creates a vicious cycle of regular use (abuse), from which individuals may struggle to break free without guidance or counseling.
  2. Dependence:

    • Dependence refers to the body’s tendency to exhibit withdrawal symptoms if regular drug/alcohol use is abruptly stopped.
    • Withdrawal symptoms can include anxiety, shakiness, nausea, and sweating, which may be relieved when substance use is resumed.
    • In severe cases, withdrawal symptoms can be life-threatening, necessitating medical supervision.
    • Dependence often leads individuals to prioritize obtaining substances over social norms, resulting in social adjustment problems.

7.5.3 Effects of Drug/Alcohol Abuse

  1. Immediate Adverse Effects:

    • Reckless behavior, vandalism, and violence.
    • Excessive doses can lead to coma and death due to respiratory or heart failure, or cerebral hemorrhage.
    • Combining drugs with alcohol increases the risk of overdosing and death.
  2. Warning Signs of Abuse:

    • Drop in academic performance and unexplained absence from school/college.
    • Lack of interest in personal hygiene, withdrawal, isolation, depression, and fatigue.
    • Aggressive and rebellious behavior, deteriorating relationships with family and friends.
    • Loss of interest in hobbies, changes in sleeping and eating habits, fluctuations in weight and appetite.
  3. Far-Reaching Implications:

    • Financial distress leading to stealing to support the addiction.
    • Impact on the mental and financial well-being of the entire family and friends.
  4. Health Risks:

    • Intravenous drug use increases the risk of serious infections like AIDS and Hepatitis B due to sharing of infected needles and syringes.
    • Chronic infections like AIDS and Hepatitis B are ultimately fatal and can be transmitted through sexual contact or infected blood.
  5. Long-Term Effects:

    • Alcohol use during adolescence may lead to heavy drinking in adulthood.
    • Chronic drug and alcohol use damages the nervous system and liver, leading to conditions like cirrhosis.
    • Drug and alcohol use during pregnancy adversely affects the fetus.
    • Misuse of drugs by certain athletes to enhance performance can lead to severe side effects such as masculinization, increased aggressiveness, mood swings, and physical abnormalities.

7.5.4 Prevention and Control

  1. Avoiding Undue Peer Pressure:

    • Respect and nurture each child’s individual choices and personality.
    • Do not push children beyond their limits in studies, sports, or other activities.
  2. Education and Counselling:

    • Educate adolescents about facing problems and stresses in life.
    • Teach them to accept disappointments and failures as part of life.
    • Encourage healthy pursuits like sports, reading, music, yoga, and extracurricular activities.
  3. Seeking Help from Parents and Peers:

    • Encourage adolescents to seek help from parents, trusted peers, or close friends.
    • Parents and peers can provide guidance, support, and a listening ear.
    • Venting feelings of anxiety and guilt can be helpful in coping with challenges.
  4. Recognizing Danger Signs:

    • Parents, teachers, and friends should be alert to signs of drug or alcohol abuse.
    • If someone is using drugs or alcohol, it’s important to bring it to the attention of parents or teachers.
    • Proper diagnosis and understanding of underlying causes are crucial for initiating appropriate measures or treatment.
  5. Seeking Professional and Medical Help:

    • Encourage affected individuals to seek help from qualified psychologists, psychiatrists, and de-addiction and rehabilitation programs.
    • With professional help and personal effort, individuals can overcome drug/alcohol abuse and lead a normal, healthy life.

 

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