Questions: Human Health and Disease

Q1. Name the pathogen and the mode of transmission for typhoid and malaria.

Answer (English): Typhoid is caused by the bacterium Salmonella typhi, and it spreads through food and water contaminated with the faeces of an infected person. Malaria is caused by the protozoan Plasmodium, with Plasmodium vivax, Plasmodium falciparum and Plasmodium malariae infecting humans, and it spreads through the bite of the infected female Anopheles mosquito, which acts as the vector.

Hinglish: Typhoid Salmonella typhi bacteria se hota hai aur infected person ke faeces se contaminated food/water se failta hai. Malaria Plasmodium protozoa se hota hai (vivax, falciparum, malariae) aur infected female Anopheles mosquito ke bite se failta hai, jo vector hai.

Q2. Why does a person with AIDS die of infections that a healthy person would survive?

Answer (English): HIV infects the helper T lymphocytes, which coordinate the whole immune response. The virus multiplies inside these cells and destroys them, so the helper T cell count falls steadily. The B cells and the T cells that depend on the help of the helper T cells cannot mount an effective response, so the immune system weakens. The person then becomes open to opportunistic infections by bacteria, fungi and parasites that a healthy immune system would control easily. AIDS is therefore a deficiency of immunity acquired during life, and death is usually due to these secondary infections rather than to the virus itself.

Hinglish: HIV helper T lymphocytes ko infect karta hai jo poore immune response ko coordinate karte hain. Virus unke andar multiply hokar unhe khatam karta hai, isliye helper T cell count girta jata hai aur B/T cells effective response nahi de pate. Isse immune system weak ho jata hai aur opportunistic infections easy ho jate hain. AIDS acquired immunodeficiency hai aur death usually virus se nahi, in secondary infections se hoti hai.

Q3. Explain innate immunity and its four types of barriers.

Answer (English): Innate immunity is present from birth, is not specific to a pathogen and has no memory. Its four barriers are the physical barriers, which are the skin and the mucus lining of the respiratory, digestive and genital tracts; the physiological barriers, which include the acidic gastric juice, saliva and tears; the cellular barriers, which are the white blood cells such as polymorphonuclear leucocytes, monocytes, natural killer cells and macrophages that engulf the microbes; and the cytokine barriers, which are the interferons released by virus-infected cells that protect the neighbouring uninfected cells.

Hinglish: Innate immunity janm se hoti hai, specific nahi hoti aur memory nahi rakhti. Iske chaar barriers hain: physical (skin aur respiratory, digestive, genital tract ki mucus lining), physiological (gastric juice, saliva, tears), cellular (leucocytes, monocytes, natural killer cells aur macrophages jo microbes ko phagocytose karte hain) aur cytokine (interferons jo virus-infected cells release karte hain aur uninfected cells ko bachate hain).

Q4. Differentiate between the humoral immune response and the cell-mediated immune response.

Answer (English): In the humoral immune response the B lymphocytes produce antibodies that are released into the blood, and these antibodies bind the antigens and neutralise the pathogen; because the antibodies are found in the body fluids, the response is also called antibody-mediated. In the cell-mediated immune response the T lymphocytes act directly, attacking the cells that the pathogen has infected, and the T cells also help the B cells to make antibodies.

Hinglish: Humoral response mein B lymphocytes antibodies banate hain jo blood mein release hote hain aur antigen se bind hokar pathogen ko neutralise karte hain; antibodies body fluids mein hote hain isliye ise antibody-mediated response bhi kehte hain. Cell-mediated response mein T lymphocytes directly infected cells ko attack karte hain aur B cells ki help bhi karte hain. Humoral arm cell ke bahar wale pathogens ke liye best hai aur cell-mediated arm unke liye jo cells ke andar chhipe hote hain; dono mil kar kaam karte hain.

Q5. What is the difference between active and passive immunity? Give one example of each.

Answer (English): Active immunity is produced when the person's own immune system makes antibodies in response to an antigen, as after an infection or a vaccination. It takes time to develop but it lasts a long time because memory cells are formed. Passive immunity is produced when ready-made antibodies are given from outside, as when a newborn receives IgA antibodies in the colostrum from the mother's milk, or when a person bitten by a snake is injected with antivenom.

Hinglish: Active immunity tab banti hai jab apna immune system antigen ke response mein antibodies banata hai, jaise infection ke baad ya vaccine se; ismein time lagta hai par memory cells banne se ye lambi chalti hai. Passive immunity tab milti hai jab ready-made antibodies bahar se diye jayein, jaise newborn ko maa ke colostrum se IgA milta hai ya snake bite par antivenom diya jata hai; ye jaldi protection deti hai par thodi der chalti hai kyunki patient ke andar memory cells nahi bante.

Q6. What is a vaccine and how does it produce immunity?

Answer (English): A vaccine is a preparation of antigens from a pathogen, given in a killed, weakened or inactivated form, or of its toxoid or a part of its surface protein. The immune system recognises these antigens and produces antibodies and memory B and T cells without the person having to suffer the disease. When the actual pathogen later enters the body, the memory cells produce a rapid and strong secondary response, so the pathogen is cleared before it can cause illness.

Hinglish: Vaccine pathogen ke antigens ka preparation hota hai, killed, weakened ya inactivated form mein, ya toxoid ya surface protein ke roop mein. Immune system un antigens ko pehchan kar antibodies aur memory B/T cells bana leta hai bina bimari hue. Jab asli pathogen baad mein aata hai to memory cells tez aur strong secondary response dete hain, isliye bimari nahi hoti.

Q7. What is cancer? Explain metastasis and contact inhibition.

Answer (English): Cancer is a disease in which some cells lose the normal control on their division and multiply repeatedly to form a mass called a tumour. Normally a cell stops dividing when it comes in contact with its neighbours, and this property is called contact inhibition; in cancer cells this property is lost, so the cells keep dividing. A tumour that remains at its original place is benign, while one that invades and spreads to distant organs through the blood and the lymph is malignant. The spread of the malignant cells to other parts of the body is called metastasis,

Hinglish: Cancer mein kuch cells apni division ka control kho dete hain aur baar baar divide hokar tumour bana lete hain. Normal cell padosi cells ke contact par divide karna band kar deta hai, ise contact inhibition kehte hain; cancer cells mein ye kho jati hai isliye woh divide karte rehte hain. Jo tumour apni jagah rehta hai woh benign hai aur jo invade karke blood aur lymph se door ke organs tak pahunchta hai woh malignant hai. Malignant cells ka door tak phailna metastasis kehlata hai aur isi wajah se cancer ka ilaaj mushkil hota hai.

Q8. Name the source plants of heroin, cannabinoids and cocaine.

Answer (English): Heroin is obtained by the acetylation of morphine, which is extracted from the latex of the unripe capsules of the opium poppy, Papaver somniferum. The cannabinoids are obtained from the inflorescences of Cannabis sativa, and its flower tops, leaves and resin are used to make marijuana, hashish, charas and ganja. Cocaine is obtained from the coca plant Erythroxylum coca, which is native to South America.

Hinglish: Heroin morphine ke acetylation se banti hai, aur morphine opium poppy Papaver somniferum ke unripe capsules ke latex se milti hai. Cannabinoids Cannabis sativa ke inflorescence se milte hain aur uske flower tops, leaves aur resin se marijuana, hashish, charas aur ganja banate hain. Cocaine coca plant Erythroxylum coca se milti hai jo South America ki native hai.

Q9. What are the warning signs of drug abuse among the youth and how can it be prevented?

Answer (English): The warning signs include a change in friends and daily habits, a drop in academic performance, a loss of interest in hobbies and sports, a change in sleeping and eating patterns, secrecy about money and whereabouts, and mood changes and irritability. Prevention works through education and awareness about the harm of drugs and alcohol, counselling and the support of parents and teachers, and involvement in sports, music and other productive activities that give the young person a sense of achievement.

Hinglish: Warning signs mein friends aur habits ka badalna, padhai ka girna, hobbies aur sports mein interest khatam hona, neend aur khane ka pattern badalna, paise aur aane-jaane ke baare mein chhipana, aur mood aur irritability shamil hain. Prevention education aur awareness, counselling, parents aur teachers ka support, aur sports/music jaise productive activities se hoti hai jisse young person ko achievement ka feeling milta hai.

Q10. Why is the thymus important for immunity and what happens if it is removed at an early age?

Answer (English): The thymus is a primary lymphoid organ in which the T lymphocytes mature into antigen-sensitive cells. After maturation the lymphocytes migrate to the secondary lymphoid organs such as the spleen, lymph nodes and tonsils and take part in the immune response there. If the thymus is removed or shrinks at an early age, the maturation of the T lymphocytes is affected, so the number of mature T cells falls and cell-mediated immunity is weakened.

Hinglish: Thymus primary lymphoid organ hai jahan T lymphocytes mature hokar antigen-sensitive cells banate hain. Maturation ke baad ye lymphocytes secondary lymphoid organs (spleen, lymph nodes, tonsils) mein ja kar immune response mein hissa lete hain. Agar thymus early age par nikal diya jaye ya sookh jaye to T lymphocytes ki maturation affect hoti hai, mature T cells kam ho jate hain aur cell-mediated immunity kamzor ho jati hai. Isse person infections ke liye zyada open ho jata hai, jaise age ke saath thymus ke degenerate hone par hota hai.

Quiz below: five questions on the pathogens, immunity, AIDS, cancer and drug abuse. Write the pathogen or the term with every answer.