Understanding Common Diseases, Drugs, and Their Effects
Diseases and Their Impact on Health
Diseases are functional or organic disorders that negatively affect human well-being.
Infectious Diseases
Infectious diseases are transmitted through infection. Transmission can occur through:
- Direct contact with infected individuals or contaminated objects.
- Inhaling water droplets or saliva containing germs.
- Consuming contaminated food or water.
- Insect vectors.
- Indirect contact.
The body has evolved defenses to prevent microorganism entry, including:
- Skin
- Mucous membranes
- Macrophages
These act as the first barrier. When foreign elements (antigens) are detected, the body initiates a response.
Autoimmune Diseases: Multiple Sclerosis
Multiple sclerosis is a central nervous system disease affecting the brain and spinal cord. Myelin, a protein and fat substance surrounding nerve fibers, facilitates nerve impulse conduction. Damage to myelin disrupts signal transmission between the brain and body, leading to symptoms such as:
- Muscle weakness
- Tingling
- Slurred speech
- Balance disorders
- Visual disturbances
- Tremors
- Memory disorders
Neoplastic Diseases: Cancer
Cancer occurs when cells divide uncontrollably, forming tumors. These tumors can remain localized or metastasize (invade other tissues). Cancer has a high mortality rate, and treatments often have debilitating side effects.
Mental Illness
Mental illnesses encompass a diverse group of disorders affecting thinking, feelings, emotions, and behavior.
Drugs and Their Effects
Drugs are substances that alter mood, perception, or cognition, often leading to dependence or tolerance.
Types of Drugs
- Depressants: (e.g., alcohol, sedatives, opioids) slow down the central nervous system, impairing brain function and reaction time.
- Stimulants: activate the central nervous system, causing effects ranging from insomnia to hyperactivity.
- Hallucinogens: distort perception.
Alcohol
Alcohol initially causes euphoria and disinhibition, followed by drowsiness, sadness, and depression. Dependence can lead to withdrawal symptoms. Abuse can cause digestive and circulatory system diseases.
Smoking
Smoking can cause lung, larynx, and stomach cancer, chronic bronchitis, emphysema, and cardiovascular disease. Passive smoking affects those nearby. Life expectancy is reduced by 15-20 years.