Understanding Human Health: Diseases, Immunity, and Healthy Lifestyles
Occasionally, our body is altered, or we experience an illness.
Health
A person is healthy when all organs are fully functional and they feel good physically, mentally, and socially. Health is a quality where the body and all its systems perform their duties properly.
Disease
At times, the activity of the body or any of its organs is altered, leading to malfunctions. This is what we know as disease. A disease is a continuing alteration in the functioning of the body.
1.1 Types of Diseases
Infectious diseases are caused by germs or viruses that enter our body and multiply inside. They are acquired by contagion.
Non-infectious diseases: These are not contagious and can be caused by:
- Poor eating habits: Nutritional deficiencies or hazardous substances like drugs, alcohol, or tobacco.
- Environmental Factors: Pollution or social stress.
- Shock and Trauma: Injuries from accidents.
- Impairment of organs with age: Due to wear and tear.
- Genetic abnormalities: Caused by genes with incorrect information.
The Causal Agents of Infectious Disease
Pathogenic microbes (from pathos “disease” and geno “generate”) and viruses are parasites that infect a living organism (host) to use its resources. The infection causes disruption of the body characteristic of each disease.
Types of Pathogens
- Fungi: Eukaryotic multicellular organisms. Some cause diseases like candidiasis, ringworm, or Athlete’s foot.
- Bacteria: Unicellular prokaryotic organisms. They cause diseases such as salmonellosis, meningitis, or pneumonia.
- Protozoa: Unicellular eukaryotic organisms. They cause diseases such as toxoplasmosis, dysentery, and sleeping sickness.
- Viruses: These lack cellular organelles and must parasitize other cells to reproduce. They produce diseases such as measles, influenza, or chickenpox.
The power possessed by pathogenic microbes and viruses to cause disorders, known as Virulence, depends on two factors: their toxic ability and invasiveness.
2. The Transmission of Infectious Diseases
When people and animals are infected by germs, they are considered sources of infection. Soil, water, air, and food are transmission facilities where they can spread.
Forms of Transmission
Pathogens can be transmitted from a source to a healthy body in two ways:
- Direct transmission or contagion: Occurs when a person carrying germs transfers them to a healthy person through physical contact or particles.
- Indirect transmission: Occurs from a carrier to a healthy person without direct contact, such as through inhaling dust, air, or water.
When animals are transport agents, the germs are called disease vectors.
Entrance Ways
Microbes must pass through barriers to enter the body. Skin injuries provide entry points. Mucous membranes prevent the entry of many microbes and viruses, but some can bypass these barriers. Entry occurs through:
- Airway: The respiratory mucosa can be penetrated by some airborne viruses.
- Digestive tract: Bacteria can contaminate food or water.
- Genitalia: Germs are transmitted through sexual contact.
4. The Body’s Defense
The skin and mucous membranes lining internal pathways are barriers that prevent the entry of large numbers of germs.
5. The Local Response: The Response to a Wound
6. Phagocytes
Phagocytes are white blood cells that engulf and destroy germs. Sometimes the wound area becomes inflamed and red, with a rise in temperature, known as the inflammatory response. This is because cells release substances in the injured area, causing:
- Dilation of blood vessels: Increases blood supply and transports phagocytes.
- Increased local temperature: Promotes phagocyte mobility.
Pus is formed at the site of inflammation and comprises the remains of bacteria-laden white blood phagocytes.
The General Response: The Immune Response
If germs spread throughout the body, it causes an infection called sepsis. Our body has a defensive line: lymphocytes. Lymphocytes are white blood cells responsible for making antibodies.
The entry of germs triggers an immune reaction, carried out by the immune system:
- A germ is intercepted and engulfed by a phagocyte.
- The phagocyte carries components of the germ and exposes them to lymphocytes.
- This sensitized cell multiplies, creating others capable of making antibodies.
- Some lymphocytes release antibodies into the blood, facilitating germ destruction.
- Others recognize and destroy infected cells in our body.
The Immune System’s Memory
Some diseases occur only once because sensitized lymphocytes create immune memory. Thus, upon new contact with the same germ, the defensive response is fast, preventing the disease. This provides natural immunity, such as with measles. Sometimes, viruses change, and sensitized lymphocytes no longer recognize them, allowing reinfection, such as with influenza.
5. Medical Assistance: Vaccines
After recovering from an infection, your body is immune. We can achieve artificial immunity through vaccination.
Vaccination involves introducing a weakened or inactive virus or its components. Vaccines are artificial preparations containing killed or attenuated bacteria or viruses, or their disabled components. Vaccination aims to protect against specific infections and is one of the most effective public health measures. Children should be vaccinated from birth to 14 years. The immunization schedule is flexible and can be modified based on the population’s health status.
Serums
Sera are artificial preparations containing antibodies against disease-causing agents.
Antibiotics
In 1929, Alexander Fleming observed that bacteria could not grow around mold. He isolated substances from the mold that prevented bacterial growth.
The first known antibiotic was penicillin.
Antibiotics are substances produced by fungi and bacteria that prevent the growth of pathogenic microorganisms.
6. Lifestyles and Health
7. Factors Affecting Our Health
Factors affecting our health include:
- Eating habits: Cardiovascular problems and cancer are associated with poor eating habits.
- Overweight and obesity are serious health problems, increasing the risk of diseases like diabetes.
- Drug use: Affects physical and mental health, including:
- Tobacco
- Alcohol, a source of many diseases, injuries, and violence.
- Illegal drugs, directly responsible for thousands of deaths annually in Europe, often related to accidents and violence.
- Psychological factors: The severity of mental disorders caused by stressful lifestyles is often underestimated.
7. Healthy Lifestyle
A healthy lifestyle involves adopting healthy habits and hygiene measures:
- Personal Actions: Sports and outdoor activities, regular schedules, balanced diet, avoiding toxic substances, brushing teeth, daily grooming.
- Social Measures: Access to healthcare, sanitary control, waste management, pet health control.
Hygiene is a set of habits and rules that must be practiced to maintain good physical condition and prevent diseases.