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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

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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.

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

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

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

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

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

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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).

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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^+, Cl−Cl^-). 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 10−1510-15 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.