Diseases and First Aid

The “Diseases and First Aid” chapter in your ICSE Class 8 Biology book is all about understanding what disrupts our health, how those disruptions spread (in some cases), and what we can do to help, especially in emergencies.

Here’s a breakdown:

• What is a Disease? It starts by explaining that a disease is any condition that throws the body off its normal, healthy state. It’s not just about catching a cold; it’s any time your body isn’t working as it should.
• Types of Diseases: The chapter usually divides diseases into two main categories:
  • Communicable Diseases: It often discusses vectors, which are organisms (like mosquitoes) that carry these diseases.
  • Non-Communicable Diseases: These are the ones you can’t “catch” from someone else. Examples include things like diabetes, heart disease, or vitamin deficiency diseases.
• How Diseases Spread: A key part of this is understanding how communicable diseases are transmitted. This could be through direct contact, through the air (like when someone coughs), through contaminated food or water, or through those vectors we mentioned.
• Prevention is Key: The chapter emphasizes how important it is to prevent diseases in the first place. This often includes:
  • Public Hygiene: Keeping our surroundings clean to stop diseases from spreading.
  • Vaccination and Immunization: How vaccines work to protect us from specific diseases.
• First Aid: The second major part of the chapter deals with what to do immediately when someone gets hurt or suddenly becomes ill. It covers the basic steps for handling common emergencies, such as:
  • Burns
  • Bleeding
  • Fractures (broken bones)
  • Objects in the eye
  • Unconsciousness
  • Swallowing Poison
  • Snake Bites
  • Stings
• Harmful Habits: The chapter also usually touches on the dangers of things like tobacco, alcohol, and drugs, explaining how they can damage your health.

REVIEW QUESTIONS

Multiple Choice questions:

1. Put a tick mark (✓) against the correct alternative in the following statements:

(a) A mosquito is a vector for

1. Typhoid
2. Cholera
3. Malaria
4. Jaundice

(b) Dengue is caused by a

1. Protozoan
2. Virus
3. Worm
4. Fungus

(c) The idea of vaccination was conceived by

1. Charles Darwin
2. Alexander Flemming
3. Issac Newton
4. Edward Jenner

(d) Which one of the following is not a psychotropic drug ?

1. Morphine
2. Cocaine
3. Heroin
4. Penicillin

(e) Which one of the following is a communicable disease ?

1. Measles
2. Cancer
3. Heart stroke
4. Allergy

(f) Cataract is a disease of: –

1. Ears
2. Nose
3. Eyes
4. Throat

(g) Infectious diseases can be prevented by:

1. Medicines
2. Proper food
3. Immunisation
4. Exercise

(h) Which one of the following is a genetic disease ?

1. Scurvy
2. Leukemia
3. Goitre
4. Haemophilia

(i) Which one of the following is a degenerative disease ?

1. Thalassemia
2. Beri-beri
3. Cataract
4. Diabetes

(j) Pellagra is one disease caused by the deficiency of:

1. Vit. B3
2. Vit. B1
3. Vit. C
4. Vit. D

(k) Hay fever and asthma are

1. Deficiency diseases
2. Genetic diseases
3. Organic diseases
4. Allergy diseases

(I) Which one of the following vitamin deficiency diseases can be cured by eating a diet which includes carrot, yellow fruits, vegetables, butter, milk, fish ?

1. Beri-beri
2. Dermatitis
3. Night blindness
4. Scurvy

Short Answer Questions:

Question 1(a).
What is a non-communicable disease ?
Answer:
Non-communicable diseases are illnesses that don’t spread from person to person like infections do. ¹ Instead, they usually develop due to a combination of our genetic makeup, our lifestyle choices, and the environment we live in. ² So, unlike a cold or flu, you can’t “catch” a non-communicable disease from someone else.

Question 1(b).
What are communicable diseases ?
Answer:
Communicable diseases are essentially contagious illnesses, meaning they have the ability to spread from one living being to another – be it person to person, or even from animals to us. This transmission can occur through a variety of pathways: direct physical contact with someone who is ill, breathing in the tiny droplets an infected individual releases when they cough or sneeze, or even by encountering contaminated food, water, or everyday items. So, if an illness possesses this characteristic of being transmissible, it’s classified as a communicable disease.

Question 1(c).
How can we control the spread of diseases by mosquitoes and houseflies ?
Answer:
To curb diseases spread by mosquitoes and houseflies, we should:

• Eliminate their breeding grounds (stagnant water, waste).
• Use barriers like screens and nets.
• Apply repellents and insecticides cautiously.
• Maintain good hygiene and sanitation.

Question 1(d).
Public hygiene is equally important as personal hygiene. Give reasons.
Answer:
Disease Prevention: Poor public hygiene fosters germs, causing widespread illness. Clean public spaces protect everyone from outbreaks.

Community Health: Public hygiene boosts overall well-being and lessens the community’s disease burden, leading to healthier individuals.

Economic Impact: Poor sanitation leads to widespread sickness, hurting productivity and increasing healthcare costs. Good public hygiene supports a productive society.

Social Responsibility: Maintaining clean public spaces is a shared duty showing a community’s care for everyone’s health.

Question 1(e).
What is a deficiency disease ?
Answer:
A deficiency disease is an illness that arises when the body doesn’t get enough of a specific nutrient, like a vitamin or mineral, over a prolonged period. Think of it as your body’s way of showing signs of trouble because it’s missing a crucial building block or essential component it needs to function properly.

Question 1(f).
Biting nails should be strictly avoided. Give a reason.
Answer:
Biting your nails opens up tiny cuts in the skin around them. These little breaks become doorways for nasty germs like bacteria, viruses, and fungi to sneak in. Once inside, these germs can cause painful infections in your fingers and even under your nails. Plus, chewing on your nails moves any dirt and germs that are hanging out there straight into your mouth, making it more likely you’ll get sick. So, kicking this habit is a simple and direct way to protect your health.

Question 1(g).
Regular exercise and proper rest is a must. Give a reason.
Answer:
Staying active and getting enough rest are key for a healthy body and mind. Exercise makes you stronger, helps manage weight, boosts immunity, and sharpens focus and mood while reducing stress. Rest lets your body and brain recover and work well. Skipping either can lead to tiredness, poor performance, and health problems. They’re essential for a balanced life.

Question 1(h).
Children eating more fast food tend to suffer from obesity (overweight). Comment.
Answer:Too much fast food can make kids overweight because it’s packed with calories, bad fats, sugar, and salt, while missing important nutrients their bodies need to grow healthy. Eating a lot of it regularly makes weight gain and obesity more likely for children.

2. Name the following:

Question 2(a).
A viral disease caused due to unhealthy sexual contact
Answer:
A viral disease that can spread through unprotected sexual contact is definitely HIV/AIDS (Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome).

It’s true that other viral infections, such as genital herpes, human papillomavirus (HPV), and Hepatitis B, can also be sexually transmitted. However, HIV/AIDS stands out as a significant viral illness directly linked to engaging in risky sexual practices.

Question 2(b).
A disease caused due to Plasmodium
Answer:
Malaria begins when tiny parasitic protozoa, specifically from the Plasmodium group, invade our red blood cells. Their entry and subsequent activity within these blood cells are the direct cause of the telltale signs and symptoms of this disease.

Question 2(c).
A disease caused by the bite of female Anopheles mosquito
Answer:
Malaria’s spread follows a specific route: it happens when a female Anopheles mosquito bites someone and draws their blood. That’s the key moment of transmission.

Question 2(d).
Two viral diseases caused by mosquito bites
Answer:
Dengue usually hits you with a high fever and then throws in a really bad headache, pain when you move your eyes, achy muscles and joints, a sick feeling in your stomach (sometimes leading to vomiting), and a rash. It’s also important to know that Dengue can sometimes become very serious.

Chikungunya, on the other hand, often starts with a sudden spike in your temperature and really, really intense pain in your joints. Besides that, you might also get a headache, muscle pain, swelling around your joints, and a rash. A key thing about Chikungunya is that the joint pain can be incredibly severe and can unfortunately last for quite a while.

Question 2(e).
Any droplet — borne disease.
Answer:
A concise way to describe an illness that spreads via those microscopic liquid particles we expel when we cough or sneeze is:

Airborne droplet transmission.

It perfectly encapsulates how the sickness travels – through the air in those tiny droplets.

Question 2(f).
A viral disease caused by the bite of a dog
Answer:
Rabies is definitely a viral illness that can be transmitted to people when they’re bitten by a dog infected with the virus.

Question 2(g).
A disease due to choking of coronary artery
Answer:
Coronary Artery Disease, often abbreviated as CAD, develops when the arteries that supply blood to your heart become narrowed or even completely blocked. Think of these arteries as vital pipelines delivering essential oxygen and nutrients to your heart muscle. When these pipelines get clogged up – the medical term for this is stenosis – the flow of blood is restricted.  

And you’re spot on about the serious consequences. If this narrowing becomes severe or a complete blockage occurs, it can lead to a heart attack. This happens because the heart muscle isn’t getting enough blood, and without that constant supply, it can become damaged. It’s a critical situation that underscores the importance of healthy arteries for a healthy heart

Question 2(h).
Two diseases caused due to deficiency of protein in the diet of a child.
Answer:
Protein is truly vital for growing children, and unfortunately, a deficiency can lead to serious health problems. A prime example is kwashiorkor, a condition that primarily arises from a severe lack of protein in their diet. You might observe it through signs like swelling, particularly in the ankles and feet, a protruding belly, changes in hair texture and color (thinning or loss of pigment), and various skin issues. Children affected by kwashiorkor can also become irritable and lose interest in their environment.

Then there’s marasmus, which develops when a child’s overall calorie intake is insufficient, encompassing a lack of protein as well. Children with marasmus often appear extremely thin and underweight due to significant muscle and fat loss. They tend to be very lean, have dry skin, and experience considerable delays in their growth. While inadequate protein contributes to this condition, the fundamental issue is a profound lack of total energy from food.

3. Write short (2-3 sentences) notes on the following:
Disease, immunisation, pathogen, AIDS, vaccination, vector.

Answer:

Disease: When something goes wrong with an organism, affecting how it’s built or how it works, and this shows up in noticeable ways, we call it a disease.

Immunisation: This is like training your body’s defense system to recognize and fight off a specific illness. Often, we do this through vaccination, which helps protect you if you ever encounter that disease in the future.

Pathogen: Think of these as tiny invaders – like bacteria, viruses, fungi, or parasites – that can get inside a living thing and make it sick by messing with its normal processes.

AIDS (Acquired Immunodeficiency Syndrome): This is a serious, long-term illness caused by the Human Immunodeficiency Virus (HIV).Vaccination: This involves introducing a weakened or inactive version of a germ (or parts of it) into your body. It’s like showing your immune system a “wanted poster” so it can learn how to recognize and attack the real germ if it ever shows up.

Vector: Imagine an organism that doesn’t cause the sickness itself but acts like a carrier, moving the disease-causing agents from one living thing to another. Think of mosquitoes spreading malaria or ticks spreading Lyme disease.

P.Q. Fill in the blanks by selecting suitable words given below:
(clotting, goitre, insuline, rickets, iron, proteins)

(a) Anaemia is caused due to the deficiency of_____

Answer:iron.

(b) Deficiency of Vit. D causes ______in children.
Answer: rickets

(c) Deficiency of iodine in the diet may cause _______.
Answer:goitre

(d) Diabetes is caused due to undersecretion of ______.
Answer: insulin.

(e) Kwashiorkor is caused due to the deficiency of _______.
Answer: proteins.

(f) Haemophilia is a disease caused due to slow ______of the blood.

Answer:clotting

P.Q. Find the odd one out:

(a) Typhoid, cholera, jaundice, tuberculosis, tetanus.
Jaundice is odd one
(b) Cold, AIDS, plague, malaria, measles.
Malaria is an odd one.
(c) Scurvy, rickets, haemophilia, pellagra, night blindness.
Haemophilia is an odd one.
(d) Proteins, carbohydrates, fats, minerals, cancer.
Cancer is an odd one.

P.Q. Fill in the blank in the following table:

Answer:

Long Answer Questions:

Question 1.
What is vaccination? Mention the four ways in which vaccines are prepared, giving the name of one disease for which each type of vaccine is used.
Answer:
Vaccines work by giving your immune system a preview of a weakened or inactive germ (or just a piece of it) so it can learn how to fight the real thing later. There are four main types: using killed germs (like the flu shot), weakened live germs (like the measles vaccine), specific parts of a germ (like the Hepatitis B vaccine), or inactivated toxins (like the tetanus shot).

Question 2.
Burns can be superficial burns, deep burns or chemical burns. What emergency care you would suggest in each case.
Answer:
Superficial: Cool with water, remove tight items, bandage, pain relief. No grease or blister popping.

Deep: Ensure safety, call emergency help. Don’t remove stuck clothing. Cover with cool, moist cloth (if possible), elevate, watch for shock. No ointments or breaking blisters.

Chemical: Protect yourself, flush with lots of cool water (brush off dry chemicals first) for 15-20 mins. Remove contaminated items. Don’t neutralize. Cover loosely, dry. Identify chemicals if safe. Emergency help for strong chemicals/large areas.

Question 3.
Describe the ways in which communicable diseases are transmitted through various indirect methods.
Answer:
Communicable diseases are quite clever in how they spread, often using routes that aren’t as obvious as direct person-to-person contact.

Consider those everyday things we handle – door knobs, shared forks and spoons, even hand towels. These are known as fomites, and they can temporarily harbor germs. If someone who’s sick touches one of these, they can leave behind a microscopic hitchhiker. Then, if you touch the same item and later touch your face (your mouth, nose, or eyes), you could unknowingly pick up the infection.

Another indirect path involves vectors, which are often animals. Think of insects like mosquitoes and ticks. They can bite someone or an animal carrying an infection, pick up the disease-causing microbes, and then transmit them when they bite someone else.

Then there’s the less appealing, but crucial to understand, fecal-oral route. This occurs when germs from feces contaminate food or water, and someone else unknowingly ingests them. This can happen due to inadequate sanitation or neglecting to wash hands thoroughly after using the toilet.

Lastly, some illnesses can even travel indirectly through the air. When someone coughs or sneezes, they release tiny droplets loaded with pathogens that can linger in the air, especially in spaces with poor ventilation. Even dust particles can carry these microscopic troublemakers and be inhaled by others.

So, while we often think of catching something by being directly near someone who’s sick, these less apparent methods highlight just how easily germs can move through our environment. This really underscores why simple habits like frequent handwashing and keeping our surroundings clean are so vital in stopping the spread of illness

Question 4.
Given a crossword puzzle. Read the clues across and clues downward, and fill up the blank squares. Check up your performance with the correct solution given at the end.

Clues across

1. Category of pathogen that causes diseases, like common cold and mumps.
2. These may readily grow in your hair, if you do not wash it regularly.
3. This is the vaccine for preventing tuberculosis.
4. Cover this part of your body by a handkerchief while sneezing to prevent droplet infection to others.
5. The disease pertussis is popularly known as whooping
6. One of the most common insects which visits our exposed foods and contaminates them.
7. A disease that weakens body’s defence system
   
8. Germ or germ – substance introduced into the body to prevent occurrence of an infectious disease.
9. A disease in which the eyes, the skin and the urine turn yellow.
10. An organ usually affected by tuberculosis.
11. A disease caused by the bite of an infected dog, and which affects the central nervous system.

Answer: