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Human Health And Disease Class 12 One-Shot | CBSE Class 12 Term 2 | Sindur Ma'am | Vedantu Enlite

Vedantu JEE English・65 minutes read

Dr. Sindhur explains the importance of revising provided PDFs before delving into human health and disease, focusing on immunity, types of acquired immunity, and examples like vaccines to stimulate antibody production. The text covers various immune system components, diseases, HIV transmission, cancer causes, drugs like opioids and cannabinoids, and the misuse of medications for insomnia and depression.

Insights

  • Immunity is the body's ability to resist infections, with innate immunity present from birth and acquired immunity developing throughout life, characterized by memory and specific responses to pathogens.
  • Different types of immunity include active immunity, where the body produces its antibodies after exposure to a pathogen, and passive immunity, involving receiving antibodies from an external source for temporary protection.
  • Various cells like T lymphocytes and B lymphocytes play crucial roles in the immune system, with vaccines stimulating antibody production for future protection against diseases.

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Recent questions

  • What is immunity?

    Immunity is the body's resistance to infections.

  • What are vaccines?

    Vaccines stimulate antibody production for protection.

  • How does passive immunity work?

    Passive immunity involves receiving ready-made antibodies.

  • What are lymphocytes?

    Lymphocytes are white blood cells crucial for immunity.

  • What is AIDS?

    AIDS is a disease caused by the HIV virus.

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Summary

00:00

"NEET Zoology: Immunity and Disease Overview"

  • The session begins with Dr. Sindhur addressing students, emphasizing the importance of revising the provided PDFs on the Telegram channel.
  • Dr. Sindhur introduces herself as a NEET zoology expert and mentions her experience and qualifications.
  • The session focuses on human health and disease, starting with immunity to ensure students are not fatigued before covering diseases.
  • Immunity is defined as the body's ability to resist foreign infections, with a strong immune system being crucial.
  • Innate immunity, present since birth, includes physical, physiological, cellular, and cytokine barriers to combat foreign substances.
  • Acquired immunity, developed throughout life, is specific and characterized by memory, with primary and secondary responses upon encountering pathogens.
  • The primary response to a pathogen is slow and of low intensity, while the secondary response, aided by memory cells, is highly intensified.
  • T lymphocytes and B lymphocytes play crucial roles in carrying out both primary and secondary responses in acquired immunity.
  • Types of acquired immunity include active (adaptive) immunity, where the body produces its antibodies after exposure to a pathogen.
  • Passive immunity, the second type, involves receiving antibodies from an external source, providing immediate but temporary protection.

19:00

Understanding Active and Passive Immunity in Vaccines

  • Active immunity involves the body producing its own antibodies, leading to the development of resistance.
  • Acquired active immunity can be natural or artificial, with natural immunity occurring when viruses enter the body naturally.
  • Vaccines are an example of artificial active immunity, stimulating antibody formation by introducing weakened pathogens into the body.
  • Common vaccines like BCG and polio vaccines are part of the immunization schedule.
  • Passive immunity involves receiving ready-made antibodies from an external source, either naturally (from the mother before and after birth) or artificially.
  • Artificial acquired passive immunity, like the rabies vaccine, involves introducing antibodies to prevent diseases like rabies.
  • Hyper-immunized horses are used to produce antibodies for vaccines like rabies, as they have strong immune systems.
  • Lymphocytes, which are white blood cells, are generated in the red bone marrow and can develop into B lymphocytes or T lymphocytes.
  • T lymphocytes, or T cells, produce clones like helper T cells, killer cells, and suppressor T cells when exposed to antigens.
  • Helper T cells aid in increasing the immune response, killer cells destroy infected cells by producing toxins, and suppressor T cells prevent the immune system from attacking the body's own cells, crucial for tissue grafting or transplantation.

38:21

"Immune System Functions and Disorders Explained"

  • Immunosuppressants are necessary to suppress the immune system in kidney transplant patients to prevent rejection.
  • Suppressor T cells suppress the immune system to prevent attacks on the body's own cells, requiring lifelong immunosuppressant intake.
  • Memory cells retain pathogen memory for future encounters, ensuring quick elimination upon re-infection.
  • T lymphocytes consist of helper cells, killer cells, suppressor cells, and memory cells, with no mention of antibodies.
  • B lymphocytes produce plasma cells for antibody production and memory cells for future antibody retention.
  • Antibodies have two light and two heavy chains joined by disulfide bonds, with variable and constant regions for specificity.
  • Vaccines contain pathogen proteins or weakened pathogens to stimulate antibody production for future protection.
  • Tetanus immunization involves injecting pre-formed antibodies for immediate immune response, constituting passive immunity.
  • Allergies result from exaggerated immune responses to allergens, with symptoms like sneezing, watery eyes, and difficulty breathing.
  • Autoimmunity occurs when the body attacks its own cells, leading to disorders like rheumatoid arthritis, psoriasis, and Hashimoto's thyroiditis.

58:53

Understanding the Immune System and Diseases

  • The immune system comprises lymphoid organs, tissues, cells, white blood cells (WBCs), and antibodies.
  • Primary lymphoid organs include the bone marrow and thymus, where immature lymphocytes mature.
  • Secondary lymphoid organs, like the spleen, lymph nodes, tonsils, Peyer's patches, and appendix, host mature lymphocytes.
  • 50% of lymphoid tissue lines major tracts in the body, protected by mucus-producing goblet cells.
  • MALT (mucosa-associated lymphoid tissue) is present in the lining of internal tracts.
  • Diseases are categorized into bacterial and viral types, with mnemonic aids for remembering them.
  • Bacterial diseases include meningitis, tetanus, tuberculosis, gonorrhea, whooping cough, pneumonia, plague, and typhoid.
  • Viral diseases encompass hepatitis, AIDS, rabies, polio, influenza, chickenpox, mumps, measles, smallpox, chikungunya, and dengue.
  • Malaria is caused by Plasmodium parasites transmitted by female Anopheles mosquitoes, with symptoms like fever, chills, hepatomegaly, and splenomegaly.
  • The malaria life cycle involves sporozoites entering the liver, replicating in red blood cells, forming gametocytes, and completing the cycle in mosquitoes.

01:21:17

HIV, AIDS, Cancer, and Drug Misuse

  • AIDS, caused by the HIV virus, has killed over 25 million people since its first reported case in 1981.
  • AIDS is transmitted through sexual contact, contaminated blood transfusions, and sharing infected needles, among other ways.
  • Infected mothers can pass HIV to their children through breast milk or the placenta.
  • HIV is transmitted through body fluids, not touch.
  • The structure of HIV includes single-stranded RNA, reverse transcriptase enzyme, inner and outer protein coats, and a lipid membrane with glycoproteins.
  • Replication of HIV involves the virus infecting a normal cell, converting its RNA to DNA using reverse transcriptase, and producing new viruses.
  • There is a time lag between HIV infection and the appearance of AIDS symptoms, known as the window period.
  • HIV replicates in macrophages and helper T cells, leading to the production of more viruses.
  • The ELISA test is used to detect HIV.
  • Cancer can be caused by carcinogens like ionizing and non-ionizing radiations, chemicals like tobacco smoke, and oncogenic viruses.
  • Tumors can be benign or malignant, with malignant tumors capable of spreading to neighboring tissues.
  • Drugs like opioids, cannabinoids, and coca alkaloids have different sources, effects on the body, and methods of intake.
  • Opioids, derived from the poppy plant, act as depressants on the central nervous system and digestive system.
  • Cannabinoids, from cannabis sativa, are stimulants and can be inhaled or taken orally.
  • Coca alkaloids, from the coca plant, stimulate the central nervous system and can cause euphoria when abused.
  • Barbiturates, amphetamines, and benzodiazepines are misused drugs used to treat insomnia and depression.
  • Morphine, used as a sedative and painkiller, is also misused as a drug.
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