Topic #6

Homeostatic Imbalance: Can lead to various diseases, impairing normal body functioning.
Disease Definition: A condition associated with impairment of normal body functioning.

Diabetes Mellitus: Result of an imbalance in blood glucose regulation, often due to destruction of pancreatic beta cells.
Role of Insulin:
- Promotes glucose uptake from blood to liver.
- Inhibits conversion of amino acids and glycerol to glucose.
Types of Diabetes:
- Type 1: Genetic disorder with little to no insulin production.
- Type 2: Result of poor diet leading to insulin overload.
Consequences of Uncontrolled Diabetes:
- Homeostatic imbalances in blood vessels, kidneys, leading to cardiovascular disease or bone disorders.

Every disease involves some form of homeostatic imbalance.
Infectious Diseases: Caused by pathogens; communicable.
- Example: Sexually transmitted infections (STIs) like gonorrhea and syphilis.
Non-infectious Diseases:
- Caused mainly by homeostatic imbalances, genetics, environmental toxins, and lifestyle choices.
- Risk Factors: Age, gender, genetic predispositions, environmental exposures (e.g., radon, toxic chemicals), and behavioral risks (e.g., smoking, diet).

Not caused by pathogens.
Causes: Genetic factors, environmental exposures, unhealthy lifestyles.
Examples:
- Cystic fibrosis, various cancers, cardiovascular diseases (e.g., coronary artery disease, hypertension).

Epidemic: Increased cases beyond what is expected in a specific area.
Outbreak: Localized epidemic.
Pandemic: Global epidemic.
Endemic: Diseases always present in a population (e.g., malaria in tropical regions).

Epidemiology: The study of patterns, causes, and effects of diseases in populations.
Concerned with infectious diseases caused by pathogens including bacteria, viruses, fungi, parasites, and prions.

Pathogens can enter through mucosae and skin, multiply inside host, and cause damage by releasing toxins.

Modes of Transmission:
- Airborne: Via droplets.
- Direct Contact: Skin contact or touching surfaces (e.g., athlete’s foot).
- Fecal-Oral: Contaminated food/water (e.g., cholera).
- Vertical Transmission: From mother to child.
- Vector-borne: Carried by vectors like mosquitos (e.g., malaria).

Many STIs are asymptomatic but can lead to serious health issues.
Symptoms: Genital sores, discharge, urinary pain.
Examples: Chlamydia, gonorrhea, HPV, HIV.
Treatment: Bacterial STIs treated with antibiotics; viral STIs managed with antivirals; vaccines available for some (e.g., HPV).

Definition: Acellular, parasitic entities, not classified as living organisms. Cannot replicate without a host cell.
Structure: Nucleic acid (DNA/RNA) in a protein coat; may have outer lipid envelope.
Classification: By nucleic acid type, and morphology (capsid structure).

Viruses can cause various diseases in humans, as well as in animals and plants. - Example: COVID-19 caused by SARS-CoV-2.
Pathway of Infection: Viral entry via receptor-mediated fusion or endocytosis.

Structure: Contains two strands of RNA and essential enzymes (reverse transcriptase, integrase, protease).
Transmission: Primarily through unprotected sexual contact, sharing needles, and from mother to child.
Treatment: HAART (Highly Active Antiretroviral Therapy); no cure, but viral load can be suppressed to undetectable levels.

Vaccination: Builds immunity against diseases; includes live or inactivated vaccines.
Antiviral Drugs: Target specific viral proteins to inhibit replication without harming host cells.
Example: Tamiflu targets neuraminidase in influenza viruses.

Prions: Infectious proteins causing neurological diseases by misfolding cellular proteins.
Cancer: Results from uncontrolled cell division; commonly associated with mutations in genes regulating the cell cycle (e.g., p53 mutations).