Human Health And Disease

Human Health and Disease: A Summary

Disease is any deviation from this state of health, caused by various factors, including pathogens, genetic disorders, lifestyle choices, and environmental factors.

Types of Diseases

Infectious Diseases: Caused by pathogens, such as bacteria, viruses, fungi, and parasites. Examples include tuberculosis, malaria, and HIV/AIDS.
Non-Infectious Diseases: Not caused by pathogens. Examples include cancer, heart disease, and diabetes.

Causes of Diseases

Genetic Disorders: Inherited diseases caused by mutations in genes.
Lifestyle Choices: Unhealthy habits like smoking, excessive alcohol consumption, and poor diet can increase the risk of certain diseases.
Environmental Factors: Pollution, exposure to toxins, and lack of access to clean water and sanitation can contribute to disease.

Immunity

Innate Immunity: Non-specific defenses that are present from birth, such as skin, mucous membranes, and white blood cells.
Acquired Immunity: Specific defenses that develop in response to exposure to pathogens. This includes both humoral immunity (mediated by antibodies) and cell-mediated immunity (mediated by T cells).

Common Diseases

Cancer
Cardiovascular Diseases: Diseases of the heart and blood vessels, such as heart attack and stroke.
Respiratory Diseases: Diseases affecting the lungs and airways, such as asthma and tuberculosis.
Digestive Diseases: Diseases affecting the digestive system, such as ulcers and hepatitis.

Public Health Measures

Prevention: Promoting healthy lifestyles, vaccination programs, and sanitation measures to prevent the spread of diseases.
Diagnosis and Treatment: Early diagnosis and effective treatment of diseases are crucial for improving health outcomes.
Healthcare Access: Ensuring that everyone has access to affordable and quality healthcare services.

Challenges in Healthcare

Emerging Diseases: The emergence of new diseases, such as COVID-19 and Ebola, poses significant challenges to public health.
Antibiotic Resistance: The increasing resistance of bacteria to antibiotics is a major public health concern.
Healthcare Disparities: Inequalities in access to healthcare services, particularly in developing countries, contribute to health disparities.

Exercise:

1. What are the various public health measures, which you would suggest as safeguard against infectious diseases?

Ans :

Public health measures are essential to prevent the spread of infectious diseases and protect the health of communities. Here are some key strategies:

Vaccination Programs

Immunization: Vaccinating individuals against preventable diseases like measles, polio, diphtheria, and tetanus can significantly reduce their occurrence.
Coverage: Ensuring high vaccination coverage rates is crucial to achieve herd immunity, protecting even those who cannot be vaccinated.

Sanitation and Hygiene

Safe Water: Providing access to clean drinking water and proper sanitation facilities can prevent the transmission of waterborne diseases like cholera and typhoid.
Hand Hygiene: Promoting handwashing with soap and water can significantly reduce the spread of germs.
Food Safety: Ensuring safe food handling and preparation practices can prevent foodborne illnesses.

Health Education

Awareness: Raising awareness about infectious diseases, their symptoms, and prevention measures.
Behavior Change: Promoting healthy behaviors, such as avoiding smoking, excessive alcohol consumption, and risky sexual practices.

2. In which way has the study of biology helped us to control infectious diseases?

Ans :

The study of biology has played a crucial role in controlling infectious diseases through:

Understanding Disease Mechanisms: Biological research has helped us understand how infectious agents like bacteria, viruses, and parasites function, reproduce, and spread. This knowledge has enabled us to develop targeted strategies for prevention and treatment.
Vaccine Development: Through the study of immunology and virology, scientists have developed vaccines that protect against a wide range of infectious diseases, such as smallpox, polio, measles, and more recent ones like COVID-19.
Antibiotic Discovery: The discovery of antibiotics, based on biological research, has revolutionized the treatment of bacterial infections. However, the emergence of antibiotic resistance has highlighted the need for ongoing research and development of new antibiotics.
Public Health Measures: Biological research has informed public health policies and interventions, such as quarantine, contact tracing, and sanitation practices, to prevent the spread of infectious diseases.
Disease Surveillance: Biological research has led to the development of diagnostic tools and surveillance systems to monitor the emergence and spread of infectious diseases, allowing for early detection and intervention.

3. How does the transmission of each of the following diseases take place?

(a) Amoebiasis (b) Malaria (c) Ascariasis (d) Pneumonia

Ans :

(a) Amoebiasis

Transmission: Through contaminated food or water containing cysts of the amoeba Entamoeba histolytica.

(b) Malaria

Transmission: The parasite Plasmodium, which causes malaria, is transmitted through the mosquito’s saliva.

(c) Ascariasis

Transmission: Through ingestion of contaminated food or water containing Ascaris lumbricoides eggs.

(d) Pneumonia

Transmission: Through inhalation of airborne droplets containing the bacteria or virus that causes pneumonia. Pneumonia can also be caused by aspiration of foreign material into the lungs.

4. What measure would you take to prevent water-borne diseases?

Ans :

Here are some effective measures to prevent water-borne diseases:

Water Treatment and Purification

Chlorination: Adding chlorine to water to kill harmful bacteria and viruses.
Boiling: Boiling water for at least 10 minutes can kill most waterborne pathogens.
Filtration: Using water filters to remove impurities and pathogens.
Disinfection: Using ultraviolet (UV) light or other disinfectants to kill microorganisms.

Proper Sanitation

Safe Water Sources: Ensuring access to safe drinking water sources, such as treated municipal water or protected wells.
Wastewater Treatment: Proper treatment and disposal of wastewater to prevent contamination of water sources.
Hygiene Practices: Promoting good hygiene practices, such as washing hands with soap and water after using the toilet or before preparing food.

Food Safety

Safe Food Handling: Practicing safe food handling techniques, such as washing hands and surfaces, to prevent contamination.
Cooking Thoroughly: Ensuring that food is cooked to a safe internal temperature to kill harmful bacteria.
Avoiding Contaminated Food: Avoiding raw or undercooked food, especially seafood and eggs, which can be contaminated with pathogens.

Personal Hygiene

Handwashing: Washing hands with soap and water before eating, after using the toilet, and after coming into contact with sick individuals.
Personal Hygiene: Practicing good personal hygiene, such as bathing regularly and avoiding sharing personal items.

Public Health Measures

Sanitation Campaigns: Implementing public health campaigns to promote awareness of water-borne diseases and preventive measures.
Infrastructure Development: Investing in infrastructure to improve water supply and sanitation facilities.
Surveillance: Monitoring for outbreaks of water-borne diseases and responding promptly to contain them.

5. Discuss with your teacher what does ‘a suitable gene’ means, in the context of DNA vaccines.

Ans :

A suitable gene for a DNA vaccine is one that:

Encodes a protective antigen: The gene should code for a protein (antigen) that is recognized by the immune system and can trigger a protective immune response. This antigen should be essential for the pathogen’s survival or infectivity.
Is conserved: The gene should be highly conserved among different strains of the pathogen, ensuring that the vaccine will be effective against a wide range of variants.
Is not essential for the host: The gene should not be essential for the survival of the host organism, as it will be removed or inactivated by the vaccine.
Is easily expressed in mammalian cells: The gene should be able to be expressed efficiently in mammalian cells, allowing for the production of large quantities of the antigen.

6. Name the primary and secondary lymphoid organs

Ans :

Primary Lymphoid Organs:

Bone Marrow: The site of B cell maturation and production.
Thymus

Secondary Lymphoid Organs:

Spleen: Filters blood, removes old red blood cells, and is a site for immune responses.
Lymph Nodes: Filter lymph fluid, containing white blood cells that help fight infections.
Tonsils and Adenoids: Located at the back of the throat and nasopharynx, respectively, they are part of the first line of defense against pathogens.
Mucosal-Associated Lymphoid Tissue (MALT): Found in the lining of the gastrointestinal tract, respiratory tract, and genitourinary tract, MALT helps protect against infections at these mucosal surfaces.

7. The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form:

(a) MALT (b) CMI (c) AIDS (d) NACO (e) HIV

Ans :

(a) MALT: Mucosal-Associated Lymphoid Tissue

(b) CMI: Cell-Mediated Immunity

(d) NACO: National AIDS Control Organization (India)

(e) HIV: Human Immunodeficiency Virus

8. Differentiate the following and give examples of each:

(a) Innate and acquired immunity (b) Active and passive immunity

Ans :

Feature	Innate Immunity	Acquired Immunity
Specificity	Non-specific (responds to a wide range of pathogens)	Specific (responds to a particular pathogen)
Response Time	Immediate	Delayed (takes time to develop)
Memory	No memory (responds the same way each time)	Has memory (responds more quickly and strongly upon re-exposure)
Components	Skin, mucous membranes, white blood cells (neutrophils, macrophages, natural killer cells), complement system	B cells, T cells, antibodies
Examples	Skin barrier, phagocytosis by macrophages, inflammation	Vaccination, recovery from an infection

Feature	Active Immunity	Passive Immunity
Source	Body’s own immune system	Obtained from outside the body
Duration	Long-lasting (can last for years or even decades)	Temporary (weeks to months)
Mechanism	Exposure to antigens stimulates the immune system to produce antibodies	Transfer of antibodies from one individual to another
Examples	Vaccination, natural infection	Maternal antibodies passed to newborn, injection of antibodies

9. Draw a well-labelled diagram of an antibody molecule.

Ans :

10. What are the various routes by which transmission of human immunodeficiency virus takes place?

Ans :

Sexual Contact:
- Anal sex: This is the most common mode of HIV transmission, especially among men who have sex with men.
- Vaginal sex: Unprotected vaginal sex can also transmit HIV.
- Oral sex: While less common, HIV can be transmitted through oral sex, particularly if there are cuts or sores in the mouth or throat.
Blood-to-Blood Contact:
- Sharing needles: Sharing needles or syringes, especially for injecting drugs, is a major risk factor for HIV transmission.
- Blood transfusions: In countries with inadequate blood screening, there is a risk of HIV transmission through unscreened blood transfusions.
- Accidental needle sticks: Healthcare workers can be exposed to HIV through accidental needle sticks.
Mother-to-Child Transmission:
- Pregnancy: HIV can be transmitted from mother to child during pregnancy.
- Childbirth: The virus can also be transmitted during childbirth.
- Breastfeeding: HIV can be transmitted through breast milk.

11. What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?

Ans : HIV (Human Immunodeficiency Virus) causes a deficiency of the immune system by targeting and destroying specific types of white blood cells called CD4+ T cells.

12. How is a cancerous cell different from a normal cell?

Ans :

Cancer cells differ from normal cells in several key ways:

Uncontrolled Growth: Cancer cells divide uncontrollably, ignoring the normal signals that regulate cell growth and division.
Loss of Differentiation: Cancer cells often lose their ability to differentiate into specialized cells, leading to abnormal cell structures and functions.
Invasion and Metastasis: Cancer cells can invade surrounding tissues and spread to other parts of the body (metastasis), forming secondary tumors.
Telomere Length: Cancer cells can maintain or even lengthen their telomeres, protective caps on the ends of chromosomes, allowing them to divide indefinitely.
Altered Metabolism: Cancer cells often exhibit altered metabolic pathways, such as increased glucose uptake and glycolysis, to support their rapid growth and division.
Genetic Instability: Cancer cells accumulate genetic mutations, leading to further abnormalities and promoting their uncontrolled growth.

13. Explain what is meant by metastasis

Ans :

These cancer cells can break away from the primary tumor, enter the bloodstream or lymphatic system, and travel to distant organs, where they can form secondary tumors.

The process of metastasis involves several steps:

Invasion: Cancer cells invade the surrounding tissues, breaking through the basement membrane and extracellular matrix.
Intravasation
Circulation
Extravasation: Cancer cells exit the bloodstream or lymphatic system and invade the tissue of a distant organ.
Angiogenesis: Cancer cells stimulate the growth of new blood vessels to supply nutrients and oxygen to the secondary tumor.

14. List the harmful effects caused by alcohol/drug abuse.

Ans :

Harmful Effects of Alcohol and Drug Abuse

Alcohol and drug abuse can have severe physical, psychological, and social consequences. Here are some of the major harmful effects:

Physical Effects

Organ Damage: Alcohol and drugs can damage organs such as the liver, heart, lungs, and brain.
Weakened Immune System: Substance abuse can impair the immune system, making individuals more susceptible to infections and diseases.

Psychological Effects

Mental Health Disorders: Substance abuse can contribute to or exacerbate mental health problems such as depression, anxiety, and psychosis.
Addiction: Chronic use can lead to addiction, making it difficult to stop using despite negative consequences.

Social Effects

Relationship Problems: Substance abuse can strain relationships with family and friends, leading to conflict and isolation.
Financial Difficulties: Substance abuse can lead to job loss, financial problems, and homelessness.

15. Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?

Ans :

Yes, friends can influence one to take alcohol or drugs. Peer pressure can be a powerful force, and it can be difficult to resist when friends or peers are engaging in these behaviors.

Here are some ways to protect yourself from such influence:

Develop strong self-esteem: Having a strong sense of self-worth can help you resist peer pressure and make your own decisions.
Identify your values: Understand what is important to you and stick to your beliefs.
Choose friends wisely: Surround yourself with friends who support your goals and values.
Learn to say no: Practice saying “no” assertively and confidently.
Find healthy alternatives: Engage in activities that you enjoy and that don’t involve alcohol or drugs.
Seek support: If you’re struggling with peer pressure or substance abuse, talk to a trusted adult, counselor, or therapist.

16. Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher

Ans :

Physical Dependence:

Tolerance: The body adapts to the substance, requiring larger doses to achieve the same effect.
Withdrawal Symptoms: Stopping use can lead to unpleasant physical and psychological symptoms, making it difficult to quit.

Psychological Dependence:

Pleasure and Reward: The brain’s reward system becomes associated with substance use, leading to cravings and compulsive behavior.
Stress Relief: Some individuals use substances to cope with stress, anxiety, or depression, making it difficult to quit without addressing these underlying issues.

Social Factors:

Peer Pressure: Social norms and peer pressure can make it difficult to resist substance use, especially in environments where it is common.
Social Isolation: Substance abuse can lead to social isolation and limited support networks, making it harder to break free from the habit.

Environmental Factors:

Easy Access: Availability of substances can make it easier for individuals to continue using.
Cultural Factors: Cultural attitudes and beliefs about substance use can influence individual behavior.

Genetic Predisposition: Some individuals may have a genetic predisposition to substance abuse, making it more difficult for them to quit.

17. In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided?

Ans :

Human evolution is a complex process influenced by various factors, including:

Brain development: Larger brain size and increased complexity.
Skeletal changes: Bipedalism, loss of opposable toes, and changes in pelvis and spine.
Dietary shifts: Transition from foraging to hunting and gathering, and later to agriculture.
Social behavior: Development of complex social structures, language, and culture.