Understanding Diseases and Illnesses

Infectious Diseases

Infectious diseases are caused by microorganisms such as bacteria, viruses, and parasitic organisms, or certain infectious proteins. These diseases are transmitted from one individual to another, accounting for about one-third of all deaths worldwide.

Zoonotic Diseases

Zoonotic infections are diseases that are initially passed from animals to humans.

Antibiotics

Antibiotics are drugs that destroy infection-causing bacteria without harming the organism's cells. They are not effective against viral infections and should not be administered in such cases.

AIDS

AIDS is an infectious disease caused by the human immunodeficiency virus (HIV), a retrovirus characterized by its small size and RNA-based genetic material. HIV can be transmitted through sexual contact, blood transfusions, needle sharing, and from mother to child during pregnancy, childbirth, or breastfeeding.

Non-Communicable Diseases

Non-communicable diseases result from alterations in body tissues and organs, causing abnormal function and disease onset.

Cancer

Cancer involves abnormal cell proliferation that leads to a tumor or neoplasia—a cell mass caused by uncontrolled healthy cell division. If the tumor does not reach blood vessels, it is benign. If it reaches the blood vessels, it becomes malignant and can invade other organs.

Cancer Risk Factors

Risk factors for cancer include tobacco and alcohol consumption, diet, and certain mutagenic viruses.

Epigenetics

Epigenetics studies environmental influences on gene expression.

Mental Illnesses

Mental illnesses are sleep disorders and intellectual function impairments seemingly unrelated to injury or abnormal brain function. Some important mental illnesses include:

• Depression: Profound sadness and an inability to lead a normal life.
• Schizophrenia: Severe personality disorders, a tendency to disconnect from the outside world, delusions, and hallucinations.
• Dementia: Progressive loss of intellectual functions. Two major types are senile and presenile dementia.

Neurodegenerative Diseases

Neurodegenerative diseases are illnesses caused by nerve cell degeneration in specific brain areas.

Alzheimer's Disease

Alzheimer's is a progressive, incurable, degenerative brain disease affecting approximately 5% of the population over 65. Patients lose their memories and ability to think, and their behavior changes. In the final stage, they become passive and unable to perform basic activities.

Parkinson's Disease

Parkinson's involves the deterioration of neurons controlling involuntary muscle movement.

Autoimmune Diseases

Autoimmune diseases are caused by an immune system malfunction, where the body recognizes its own cells as foreign.

Antibodies

Antibodies are proteins produced to counteract antigens.

Immunity

Immunity is the ability to defend against foreign substances, pathogens, and cancerous cells. There are two types: nonspecific immunity (entry barriers, inflammation, complement, and killer cell systems) and specific immunity.

Vaccination

Vaccination involves introducing dead or inactivated viruses into the body, prompting the production of memory lymphocytes.

• Active Immunity: The body produces antibodies against an antigen after contact.
• Passive Immunity: Antibodies produced by another organism are provided.

Clinical Analysis Types

Common clinical analyses include blood counts (blood cell determination), biochemical analyses (studying other blood components), and urine analysis.