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Biology - Health and Hygiene (Common Diseases, Modes of Transmission, First Aid)

Grade 9ICSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Health is defined by the WHO as a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.

Diseases are broadly classified into Communicable (Infectious) and Non-communicable (Degenerative, Deficiency, or Genetic).

Pathogens are disease-causing microorganisms including Bacteria (e.g., Vibrio choleraeVibrio\ cholerae), Viruses (e.g., RhinovirusRhinovirus), Protozoa (e.g., PlasmodiumPlasmodium), and Fungi.

Modes of transmission include Direct contact, Droplet infection (e.g., TuberculosisTuberculosis), and Indirect transmission via Vectors like the female AnophelesAnopheles mosquito for Malaria.

Bacterial diseases often treated with antibiotics include Typhoid (caused by Salmonella typhiSalmonella\ typhi) and Cholera (caused by Vibrio choleraeVibrio\ cholerae).

Viral diseases like AIDS are caused by HIVHIV (Human Immunodeficiency Virus), which attacks the TT-lymphocytes of the immune system.

First Aid follows the ABCABC rule: AA for Airway (clear the passage), BB for Breathing (check for respiration), and CC for Circulation (check pulse/heartbeat).

Vaccination provides artificial active immunity by introducing weakened or killed pathogens to stimulate the production of antibodies.

📐Formulae

BMI=Weight (kg)(Height (m))2BMI = \frac{Weight\ (kg)}{(Height\ (m))^2}

ORS (Oral Rehydration Solution)NaCl+C6H12O6+KCl+Na3C6H5O7ORS\ (Oral\ Rehydration\ Solution) \approx NaCl + C_6H_{12}O_6 + KCl + Na_3C_6H_5O_7

Pulse Rate=Number of beats60 secondsPulse\ Rate = \frac{Number\ of\ beats}{60\ seconds}

💡Examples

Problem 1:

Identify the pathogen and the vector responsible for the transmission of Malaria.

Solution:

Pathogen: PlasmodiumPlasmodium (a protozoan); Vector: Female AnophelesAnopheles mosquito.

Explanation:

The mosquito acts as a biological vector, carrying the PlasmodiumPlasmodium parasite from an infected person to a healthy person through a bite.

Problem 2:

A person is suffering from severe dehydration due to vomiting and diarrhea (Cholera symptoms). What immediate first aid should be administered?

Solution:

Administer ORSORS (Oral Rehydration Solution) at frequent intervals.

Explanation:

Cholera caused by Vibrio choleraeVibrio\ cholerae leads to rapid loss of water and electrolytes (Na+Na^+, K+K^+, ClCl^-). ORSORS helps restore the osmotic balance in the body.

Problem 3:

Explain the first aid procedure for a minor thermal burn on the hand.

Solution:

Hold the burnt area under cool running H2OH_2O for at least 101510-15 minutes.

Explanation:

Cooling the area stops the burning process, reduces TT (temperature) of the tissues, and alleviates pain. Do not apply ice directly as it may cause frostbite to damaged tissues.

Health and Hygiene (Common Diseases, Modes of Transmission, First Aid) Revision - Class 9 Science…