Study Notes - Human Diseases: A Systemic Approach

Objectives:
- Define basic terminology used in the study of human diseases.
- Identify the major causes of disease.
- Identify risk factors related to disease.
- Describe how health promotion and disease prevention can reduce the burden of disease.

Health:
- Defined as the state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity.
Homeostasis:
- The ability of the body to maintain a stable internal environment despite changes in external conditions.
Disease:
- A pathological condition of a bodily part, an organism, or system resulting from various causes, such as infection, genetic defect, or environmental stress, leading to the inability of the organism to function normally.
Pathology:
- The study of the nature of disease, including its causes, processes, development, and consequences.
Pathologist:
- A medical professional who studies the causes and effects of diseases, often working with tissue and fluid samples to diagnose disease.

Signs:
- Objective evidence of disease observable by a physician (e.g., rash, fever).
Symptoms:
- Subjective feelings reported by the patient (e.g., pain, fatigue).
Syndrome:
- A set of medical signs and symptoms that are correlated with each other and often associated with a particular disease.
Disorder:
- A disturbance in physical or mental health or a condition that disrupts normal functioning.

Diagnosis:
- The process of identifying a disease from its signs and symptoms.
- Involves several methods:
- Physical Examination:
  - Inspection: Visual examination of the body.
  - Palpation: Using hands to feel the body for abnormalities.
  - Auscultation: Listening to the internal sounds of the body, usually using a stethoscope.
  - Percussion: Tapping on a surface to determine the underlying structure.
  - Vital Signs: Measurements of bodily functions, such as temperature, pulse, respiration, and blood pressure.
Imaging Technologies:
- Tools used to visualize the structure and function of organs.
- Electrocardiography (ECG): Measures the electrical activity of the heart.
- Radiography (X-ray): Uses X-ray radiation to view inside the body.
- Computed Tomography (CT): Provides cross-sectional images of the body using X-rays.
- Magnetic Resonance Imaging (MRI): Uses strong magnets and radio waves to create detailed images of organs and tissues.
- Ultrasound: Uses sound waves to create images of internal body structures.
- Nuclear Medicine: Uses small amounts of radioactive material to diagnose and treat diseases.

Prognosis:
- The expected outcome of a disease, including chances of recovery and potential complications.
Categories of Disease Progression:
- Acute: Rapid onset and short duration.
- Terminal: Expected to lead to death.
- Chronic: A long-lasting condition that may not have a definitive end.
- Remission: Period during which the symptoms of disease lessen or disappear.
- Exacerbation: A worsening of symptoms or disease progression.
- Relapse: The return of disease symptoms after a period of improvement.
- Complication: An unforeseen problem that arises from a disease or its treatment.
- Sequela: A long-term or secondary effect following a disease.

Mortality:
- The state or condition of being subject to death; often measured in terms of mortality rate.
Morbidity:
- The condition of being diseased; refers to the prevalence of disease within a population.
Incidence:
- The number of new cases of a disease occurring in a specified time period.
Prevalence:
- The total number of cases of a disease in a given population at a specific time.
Epidemiology:
- The branch of medicine that deals with the incidence, distribution, and control of diseases.

Etiology:
- The study of the causes of diseases.
Pathogenesis:
- The process by which a disease progresses from the initial cause to its final effects on the host.
Idiopathic:
- Describes a disease with no known cause.

Hereditary:
- Genetic causes that can be transmitted from parents to offspring.
Congenital:
- Conditions present at birth which may result from genetic or environmental factors.
Degenerative:
- Diseases that result from the gradual degeneration of body structures.
Inflammatory, Autoimmune, Allergic:
- Diseases caused by inflammation, the immune system attacking the body, or allergens triggering responses.
Neoplastic:
- Diseases characterized by abnormal growths, such as tumors.
Metabolic:
- Disorders that disrupt normal metabolism.
Traumatic:
- Conditions resulting from physical injuries.
Nutritional:
- Diseases arising from dietary deficiencies or excesses.

Identified Risk Factors for Disease:
- Poor Nutrition
- Lack of Physical Activity
- Tobacco Use
- Excessive Alcohol Consumption
Promoting Health:
- Be Physically Active: Regular exercise as a preventive measure.
- Eat Wisely: Balanced nutrition to support health and prevent diseases.
- Maintain a Healthy Weight: Managing body weight to reduce the risk of various diseases.
- Be Tobacco Free: Eliminating tobacco use to prevent related diseases.
- Limit Alcohol: Reducing alcohol consumption to lower disease risks.
- Get Recommended Screening Tests and Immunizations: Keeping up with preventive healthcare measures to detect diseases early.
- Manage Stress: Utilizing stress management techniques to improve overall health.