Human Body Defenses and Disease Classifications
Natural Body Defenses
Constitutive Defenses
- Genetic Resistance: Our system lacks the specific receptors necessary for the entry of certain microorganisms.
- Anatomical Barriers: Prevent the entry of pathogenic agents into the body.
- Inflammatory Response: An increase in temperature induces an immune response, phagocytosis, and vasodilation, facilitating the arrival of defenses.
- Phagocytic Defense: Phagocytes destroy pathogens.
Induced Defenses
These are specific defense responses triggered by the presence of an antigen. Lymphocytes are involved; when presented with a foreign substance, they respond by producing proteins called antibodies, which act against the specific antigen, neutralizing its pathogenic effect. There are many types of lymphocytes, grouped into B and T classes. Notably, special cells called memory lymphocytes exist. When an individual comes into contact with an antigen, they acquire immunological memory. This means that upon re-exposure, the body rapidly produces a large number of antibodies that act on the antigen, preventing the pathogen from establishing itself and causing disease. Immunological memory can last from hours to a lifetime.
Artificial Medical Defenses
These are medications and medico-surgical techniques aimed at preventing disease, reducing its effects, or eliminating it.
- Surgery: Manual or instrumental intervention on the affected organ.
- Transplant: Introduction of tissue or an organ from a donor into a recipient.
- Types: Autologous (patient’s own tissue/organ), Allogeneic (from another individual of the same species), Xenotransplant (from another species).
- Main problem: Rejection. The body perceives the transplant as foreign, and its immune system responds by destroying it.
- Prevention: Histocompatibility studies and administration of immunosuppressant drugs are necessary, although this favors the appearance of many infections.
- Significance: For patients with damaged organs, a transplant is often the only means to prevent death or improve quality of life.
Infectious and Parasitic Diseases
Produced by biological pathogenic agents. They have a distinct evolution and treatment depending on the causative agent. They pass through 3 stages:
Stages:
- Incubation
- Development
- Convalescence
Causative Agents:
- Prions
- Viruses
- Bacteria
- Fungi
- Parasites (Metazoa, Protozoa)
Non-Infectious Diseases
Cancer
Occurs due to abnormal cell proliferation. Treated with surgery, radiotherapy, and chemotherapy.
Endocrine, Nutritional, and Metabolic Diseases
- Anorexia Nervosa: An eating disorder characterized by fear of weight gain and distorted body image.
- Bulimia Nervosa: An eating disorder consisting of repeated, compulsive ingestion of excessive amounts of food, followed by induced vomiting due to guilt and concern about weight.
Cardiovascular Diseases
Affect the heart and blood vessels.
- Cardiovascular Accidents (Stroke): Brain stops receiving blood.
- Heart Attack (Myocardial Infarction): A coronary artery blockage occurs; part of the heart muscle stops receiving oxygen and dies.
- Atherosclerosis: Thickening and hardening of artery walls.
- Hypertension (High Blood Pressure): Occurs when the pressure exerted by blood on arterial walls exceeds established limits.
Mental Diseases
Disorders of mixed origin that alter the cognitive and affective processes of the individual. Categories include psychosis, organic disorders, affective disorders, anxiety disorders, and neurosis.
Degenerative Diseases
Conditions in which, without apparent cause, organ and tissue damage occurs, altering their normal functioning.
- Alzheimer’s Disease: Progressive and terminal; the patient loses recent memory and their behavior changes.
- Parkinson’s Disease: Affects neurons responsible for controlling and coordinating movement.
Related Medical Concepts
Epidemiology
The science that studies the frequency of diseases in a population and the factors that define their expansion and severity.
Antimitotic
A drug that prevents nuclear division or mitosis from occurring.