Class xii, CBSE, NEET, BIOLOGY

1. Human Health & Diseases
Class XII NCERT/ CBSE
Shubhadeep Bhattacharjee

2. Unit Split up:
EXAM MARKS (PREDICTED)
AISSCE (CBSE) 12
NEET 20

3. Hitlist:
 Health & Disease
 Common diseases in humans
 Concept of immunity
 AIDS
 Cancer
 Drugs & alcohol

4.  HEALTH: Physical, mental and social wellbeing
 DISEASE: Any functional or physical change from the normal state that
causes discomfort , or disability, or impairs the health of an organism is called
a disease.
DISEASES CAUSE DETEREORATION IN HEALTH
STATE?????

5. DISEASES
CONGENITALINFECTIOUS
NON- INFECTIOUS

6.  INFECTIOUS DISEASE
 NON-INFECTIOUS DISEASE
 CONGENITAL DISEASE
• Common Cold
• Scurvy
• Arthritis
• Cardio Vascular Diseases
• Rickets
• Pneumonia
• Sickle Cell Anemia
• Haemophilia
• COVID-19
• Diabetes

7. INFECTIOUS DISEASES:
 PATHOGENS: Micro organisms that can cause a disease
( Bacteria, Virus, Protozoans, Helminths, Fungi etc.)
PATHOGEN DISEASE
Bacteria Pneumonia, Typhoid
Virus Influenza, Small pox, Chicken pox
Protozoans Malaria, Amoebiasis
Helminths Ascariasis, Filariasis
Fungi Ringworm, Athlete’s foot

8. Typhoid:
 Pathogen: Salmonella typhi
 Organ Effected: Small intestines
 Spread: Contaminated food and water
 Diagnostic Test: Widal Test
 Extreme Cases: Intestinal perforations and death
 Symptoms:
1. Sustained high fever
2. Constipation
3. Loss of Appetite
4. Stomach pain
5. Weakness
6. Headache

9. Pneumonia:
 Pathogen: Streptococcus pneumoniae or Haemophilus influenzae
 Organ effected: Alveoli and lungs
 Spread: Aerosol droplet, Sharing contaminated glasses
 Diagnosis: Alveoli filled with fluid
 Extreme cases: Lips and fingernails turn bluish
 Symptoms:
 1. Chills and fever
 2. Cough and headache

10. Common Cold:
 Pathogen: Rhinovirus
 Organ Effected: Nose and upper respiratory tract
 Spread: Aerosols and contaminated objects
 Lasts for 3-7 days
 Symptoms:
 1. Hoarseness of throat
 2. Nasal congestion and discharge
 3. Headache
 4. Tiredness

11. • Are all micro organisms
pathogenic?
• Are all pathogens micro
organisms?

12. Malaria:
 Pathogen: Plasmodium (P. vivax, P. malaria, P. falciparum)
 Vector: Female Anopheles mosquito
 Organ Effected: Liver & RBCs
 Symptoms:
 High fever after an incubation period of 14 days
 Restlessness
 Loss of appetite Early Symptoms
 Sleeplessness
 Muscular pain
 Headache Late Symptoms
 Chills

13.  As a response to the chills the body temperature keeps rising till it reaches
106F (height of fever). The patient sweats a lot and the temperature steadily
goes down to normal, till the next attack takes place after 48 hours.

14. Plasmodium has two life stages:
1. Asexual Stages: Sporozoites (Human Host)
2. Sexual Stages: Gametocytes (Anopheles Host)
• Sporozoites divide asexually to give rise to
more sporozoites
• Male and female gametocyte fuse together to
form sporozoites

15.  Anti malarial drugs: quinine, chloroquine
 Killing of mosquitoes by spraying DDT, BHC etc., and use of insect repellents,
mosquito nets etc., the disease can be controlled
• Sporozoites initially multiply in the liver and then
attack the RBCs
• Rupture of RBCs releases a toxin called haemozoin,
which is responsible for high recurring fever

16. Amoebiasis:
 Pathogen: Entamoeba histolytica
 Organ effected: Large intestine
 Carrier: Housefly
 Transmission: Contaminated food and water
 Symptoms:
 Abdominal Pain
 Constipation
 Cramps
 Stool with excess mucous and blood clots

17. Ringworms:
 Pathogen: fungi like Microsporum,
Trichophyton and Epidermophyton
 Transmission: Physical contact with an
effected individual or from soil.
Sharing towel, clothes, combs etc. with
infected person.
 Symptoms:
a. Dry and scaly lesions on skin, nails and scalp
b. Lesions are accompanied by itching.

18. Ascariasis:
 Pathogen: intestinal endoparasite of man, Ascaris
lumbricoides (Roundworm)
 Transmission: Contaminated vegetables, fruits and
water.
 Symptoms:
a. Abdominal pain
b. indigestion
c. internal bleeding
d. muscular pain
e. fever
f. anemia
g. nausea and headache
h. blockage of the intestinal passage.

19. Filariasis/
Elephantiasis:
 Pathogen: Wuchereria bancrofti and
Wuchereria malayi (filarial worm)
 Vector: female Culex mosquito
 Cause inflammation of the organs in which
they live for many years
 Affect the lymph vessels of the lower
limbs.
 Blocked lymph nodes results in swelling of
the legs.
 External genitalia may also be affected
leading to gross deformities.

20. Prevention & Control of Infectious Diseases:
 Maintenance of personal hygiene
 Maintenance of public hygiene
 Eradication of vectors and their breeding places
 Vaccination and immunization programs for diseases like polio, diptheria,
tetanus etc.
 Use of antibiotics and drugs to treat the infected person.

21. Quick Revision:
 Health
 Disease
 Types of diseases
 Pathogens/ vectors/ carriers
 Bacterial diseases ( Typhoid & Pneumonia)
 Viral disease ( Common cold)
 Protozoan disease ( Malaria & Amoebiasis)
 Fungal Disease ( Ringworm)
 Helminthic Disease ( Ascariasis & Filariasis)
 Prevention & control of infectious diseases