Chapter 7 Human Health and Disease Notes 2027 New NCERT Class 12 Biology PDF

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I am NEET dropper today I'm sharing complete notes*CHAPTER 7 - HUMAN HEALTH AND DISEASE SHORT NOTES* 🩺 *NCERT Class 12

### *8.1 HEALTH*

*Definition*: State of complete physical, mental, social well-being. *Not merely absence of disease*.

### *8.2 COMMON DISEASES IN HUMANS*

**Disease** **Pathogen** **Vector/Mode** **Symptom** **Test**

**Typhoid** *Salmonella typhi* Food/Water Sustained fever 39-40°C **Widal test**

**Pneumonia** *Streptococcus pneumoniae*, *Haemophilus influenzae* Droplets Alveoli filled with fluid -

**Malaria** *Plasmodium* **Female *Anopheles*** Chills + Fever every 3-4 days Blood smear

**Amoebiasis** *Entamoeba histolytica* Food/Water Constipation, cramps Stool test

**Ascariasis** *Ascaris* Food/Water Internal bleeding, anemia Stool test

**Elephantiasis** *Wuchereria* **Female *Culex*** Lymph nodes me swelling Blood test

**Ringworm** *Microsporum, Trichophyton* Soil, Towel Dry scaly lesions on skin -

*Malaria Life Cycle Imp Points*:  

1. *Sporozoites* → Human blood via mosquito bite → Liver → RBC → *Gametocytes*

2. *Gametocytes* → Mosquito → Fertilization → *Sporozoites* 

3. *Sexual cycle* = Mosquito, *Asexual cycle* = Human

### *8.3 IMMUNITY*

*1. Innate Immunity* = Non-specific, Birth se. 4 Types:  

*Barriers*: Skin, PMNL, Interferons, Mucous  

*2. Acquired Immunity* = Specific, Memory based  

*Active*: Antibody khud banate → Infection ya *Vaccine* se  

*Passive*: Antibody readymade milte → *Mother milk IgA*, Antitoxin

*Antibody Structure*: *Y-shaped, 4 polypeptide* = 2 Heavy + 2 Light chain. *IgG, IgA, IgM, IgE, IgD*  

*IgA* = Colostrum me, *IgE* = Allergy, *IgM* = First antibody

*Immune Response*:  

1. *Humoral* = B-cells → Antibody → Blood me

2. *Cell-mediated* = T-cells → Reject graft, Kill virus infected cell

*Allergy* = IgE + Histamine/Serotonin release. *Anti-histamine* drugs lete hain.

*Autoimmunity* = Body khud ko attack. Ex: *Rheumatoid arthritis*

### *8.4 AIDS*

*Full form*: Acquired Immuno Deficiency Syndrome  

*Pathogen*: *HIV = Retrovirus*, RNA → DNA by *Reverse transcriptase*  

*Transmission*: Sexual contact, Blood, Mother to child, Needles. *Shaking hands does not spread*

*Target cell*: *Helper T-cells* = CD4 cells  

*Test*: *ELISA* → Confirm by *Western Blot*  

*Prevention*: NACO, Safe sex, Disposable needles

### *8.5 CANCER*

*Definition*: Uncontrolled cell division = *Neoplasm/Tumor*  

*Benign* = Capsule me, Non-invasive ❌  

*Malignant* = No capsule, *Metastasis* hoti hai ✅  

*Carcinogens*: UV, X-rays, Tobacco, Viral oncogenes  

*Detection*: *Biopsy*, CT scan, MRI  

*Treatment*: Surgery, *Radiotherapy*, *Chemotherapy*, Immunotherapy

### *8.6 DRUGS AND ALCOHOL ABUSE*

**Drug** **Source** **Effect** **Organ**

**Opioids** *Papaver somniferum* Depressant, Sedative **Heroin, Smack**

**Cannabinoids** *Cannabis sativa* Cardiovascular effect **Ganja, Charas, Marijuana**

**Coca alkaloid** *Erythroxylum coca* Stimulant, Euphoria **Cocaine, Crack**

**Hallucinogen** *Atropa belladona*, *Datura* Hallucination **LSD**

**Tobacco** *Nicotiana tabacum* **Nicotine** = Stimulant Lung cancer, Emphysema

*Adolescence Period* = 12-18 years = Drug abuse ka time  

*Withdrawal syndrome* = Vomiting, Shakiness, Anxiety  

*Prevention*: Avoid peer pressure, Counseling, Help lines

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*NEET 2027 HOTSPOTS* 🔥

1. *Widal test* = Typhoid, *ELISA* = AIDS

2. *Female _Anopheles* = Malaria, *Female _Culex* = Filariasis

3. *IgA* = Colostrum, *IgE* = Allergy

4. *Heroin* = _Papaver somniferum_, *Cocaine* = _Erythroxylum coca_

5. *Metastasis* = Malignant tumor ka property

6. *HIV enzyme* = Reverse transcriptase

*1 Line Revision*:  

Typhoid-Widal, Malaria-Anopheles, AIDS-ELISA, Cancer-Metastasis, Heroin-Papaver, IgE-Allergy

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