essay 1 - health and disease. pathologic reactions, processes, conditions. etiology and pthaogenesis. basic mechanisms of disease development and progression

define health

• state of complete physical, mental and social wellbeing (WHO)

define disease

• a defined pathological process with a set of characteristic signs and symptoms, it is the manifestation of deregulated homeostasis due to intrinsic and or extrinsic factors

definistions of pathologies

• Pathological reaction = short lasting inadequate reactions of the organism to harmful stimuli such as anaphylaxis

• Pathologic processes = underlying mechanisms and local manifestations of a disease e.g prolonged hypertension leads to hypertrophy of the heart muscle

• Pathologic conditions = actual diseases or disorders resulting from pathologic reactions and processes, e.g pathologic infectious process is pneumonia

define etiology

• cause of disease, most diseases are multifactorial in origin

define extrinsic and intrinsic factors that cause a disease

• Extrinsic = biological agents (bacteria, virus), chemical agents (toxins, drugs) and physical agents (trauma, radiation)

• Intrinsic = genetics (chromosomal abnormalities), congenital (developmental defects), immunologic (allergies) and psychologic (stress-related disorders)

what is pathogenesis

• evolution of a disease process. It is the sequence of events that occur from the time of initial contact with an etiologic agent until the ultimate expression of the disease

• Cellular adaption = hypertrophy, hyperplasia, atrophy, metaplasia

• Cell injury = reversible (swelling, fatty change) or irreversible (necrosis, apoptosis)

• Inflammation = protective but may cause tissue damage

• Repair = regeneration or fibrosis

basic mechanisms of developing a disease are (abbreviation = MONCH)

1. neural regulation - autonomic imbalance - example = stress-induced tachycardia

2. hormonal regulations - endocrine imbalance - example = diabetes mellitus

3. cellular regulations - altered metabolis, apoptosis = example = cancer

4. molecular regulations - DNA/RNA mutations, enzyme defects - example = sickle cell anemia

5. organic regulations - organ-level dysfunction - example = heart failure

phases of disease progression

1. Latency = this is the silent phase, there is no symptom however the disease is present. incubation in infections

2. Prodome = this phase has very vague symptoms such as tiredness which cannot help provide a clear diagnosis. early warning stage

3. Clinical Symptoms = this phase has specific signs and symptoms for that disease and allows a clear diagnosis. diagnostic stage

4. Recovery = (complete/incomplete) or death. prognostic stage