Body Defenses, Health, and Illness: Prevention & Treatment
Body Defenses Against Illness
External Defenses: Non-specific reactions to all microorganisms. There are three types:
Physical Defenses
Separate the body’s interior from the environment. Skin covers the outside, and mucous membranes line digestive, respiratory, and reproductive cavities.
Chemical Defenses
Pathogen-blocking secretions.
Biological Defenses
Bacterial flora on skin and mucous membranes produce natural antibiotics, protecting against other pathogens.
Internal Defenses
Activated when pathogens bypass external defenses, combining to form an immune response.
Innate Immunity
Non-specific defense against any pathogen that breaches external defenses.
- Phagocytosis: Phagocytes engulf and consume unwanted materials, forming pus.
- Inflammation: Stops pathogens, causing swelling. Macrophages, defensive phagocytes, are sent to the affected area.
Acquired Immunity
Specific response to recognized antigens.
- Lymphocyte B-cells: Recognize antigens and create antibodies. Some become memory cells, storing antigen information.
- Lymphocyte T-cells: Produce enzymes that destroy pathogen-damaged cells.
Health and Illness
Health is a state of well-being in body and mind, varying from person to person and difficult to define precisely.
Determinants of Health
- Environmental: Pollution, radiation, toxins, and pathogenic microorganisms.
- Lifestyle: Balanced diet, physical exercise, stress levels, and substance consumption.
- Genetic: Genetic inheritance (disease resistance/congenital diseases), and age (health often declines with age).
The Concept of Illness
Occurs when one or more body organs malfunction, causing discomfort.
Indicators of illness:
- Symptoms: Felt or experienced by the ill person.
- Signs: Observable by others or detected in tests.
Classification of illness:
- Infectious Illness: Caused by transmittable pathogens.
- Non-Infectious Illness: Not caused by pathogens and not transmittable.
Non-Infectious Illnesses
Cardiovascular Illnesses: Heart attacks and strokes, often caused by unhealthy diet and lifestyle.
Respiratory Illnesses
Include pulmonary hypertension, bronchitis, emphysema, and asthma.
Diabetes
Involves elevated blood sugar levels. Several types exist.
Cancer
Over 100 types, all involving abnormal cell growth.
Infectious Illnesses
Direct Transmission
Pathogens transferred via physical contact or through the air.
Indirect Transmission
Transferred via an intermediary, often animals (vectors) that can transmit to humans.
Pathogens
- Bacteria: Single-celled organisms, some harmless, some cause illness.
- Viruses: Non-cellular parasites of living cells.
- Fungi: Single/multicellular eukaryotic organisms.
- Protozoa: Simple eukaryotic organisms.
Illness Prevention and Treatment
Illness Prevention
Vaccination is a key preventive measure, though not available for all illnesses. Developing personal habits is also crucial.
- Hygiene: Wash hands after using the toilet and before eating. Shower regularly, especially after sports. Cover your mouth and use tissues. Clean and disinfect cuts.
- Lifestyle: Get adequate sleep, eat a balanced diet, and avoid smoking.
Treatment
If prevention fails, infectious illnesses may develop, requiring medical treatment.
- Antibiotics: Stop bacterial growth and multiplication.
- Antivirals: Kill parasitic viruses.
- Antisera: Commonly used as antivenom.
- Fungicides: Kill or stop fungal growth.