Medical Terminology

MEDICAL TERMS REFERRING TO CERTAIN INFECTIVE PROCESSES

  • Prepared by: Roberto B. Tagalog Jr., RRT

LEARNING OUTCOMES

  • Identify the key structures and functions of:

    • Viruses

    • Bacteria

    • Protists

    • Fungi

  • Explain how viruses, bacteria, protists, and fungi spread diseases in humans and plants

  • Name examples of communicable diseases in humans and plants

INFECTIOUS DISEASES

  • Definition: Illnesses caused by harmful organisms (pathogens) entering the body from the outside.

  • Pathogens include:

    • Viruses

    • Bacteria

    • Fungi

    • Parasites

    • Rarely, prions

  • Modes of transmission:

    • From other people

    • Bug bites

    • Contaminated food, water, or soil

INFECTIOUS DISEASES VS NONINFECTIOUS DISEASES

  • Infectious Diseases:

    • Caused by harmful organisms (viruses and bacteria).

    • Examples: Flu, Measles, HIV, Strep throat, COVID-19, Salmonella

  • Noninfectious Diseases:

    • Not caused by outside organisms; can result from genetics, anatomical differences, age, environmental factors.

    • Examples: Cancer, Diabetes, Congestive heart failure, Alzheimer’s disease

TYPES OF INFECTIOUS DISEASES

  • Major types include:

    • Bacteria

    • Fungi

    • Virus

    • Parasite

    • Transmissible Spongiform Encephalopathies (TSE)

BACTERIA

  • Definition: Single-celled organisms that lack a nucleus.

  • Key features of bacterial cells:

    • Pilus: Attaches the cell surface to the host

    • Flagellum: Helps in movement

    • Plasmid: Small, circular DNA molecule

    • Plasma Membrane and Cell Wall: Provides structure and protection

    • Slime capsule: Sometimes aids bacteria in invading the host

BACTERIAL INFECTIONS

  • Bacteria are found everywhere, including in the human body.

  • While many bacteria are harmless or beneficial, some release toxins causing illness.

DISEASES CAUSED BY BACTERIA

  • Salmonella Infection:

    • Caused by: Salmonella bacteria in contaminated food.

    • Symptoms: Abdominal pain, vomiting, diarrhea.

  • Strep Throat:

    • Caused by: Group A Streptococcus bacteria.

    • Symptoms: Severe inflammation and sore throat.

  • Tuberculosis (TB):

    • Affects: Primarily lungs but can affect other organs.

    • Symptoms: Can be fatal if untreated.

  • Pertussis (Whooping Cough):

    • Respiratory infection known for severe coughing, especially in infants.

FUNGI

  • Definition: Most fungi are microscopic but some produce fruitbodies with spores.

  • Characteristics:

    • Contain a true nucleus and many membrane-bound organelles.

    • Types include yeasts, molds, and mushrooms.

FUNGAL INFECTIONS

  • Fungi reside on/in the human body; can cause illness when overgrown or when harmful fungi invade.

MAIN FEATURES OF FUNGI

  • Chitin: Provides structural stability to cell walls.

  • Spores: Main reproductive units.

  • Hyphae: Thread-like structures forming mycelium.

  • Yeast: A single-celled fungus that can reproduce through budding.

DISEASES CAUSED BY FUNGI

  • Athlete's Foot: Fungal infection causing a flaky rash between toes.

  • Cryptococcosis: Affects lungs and brain from breathing in spores.

  • Vaginal Candidiasis: Caused by Candida overgrowth, leading to burning and itching.

  • Oral Candidiasis: Common in toddlers; presents as white lesions in mouth.

VIRUSES

  • Definition: Pathogens that can only replicate within a host organism.

  • Structure includes:

    • Nucleic Acid: Contains genetic material.

    • Protein Coat (Capsid): Provides structure.

    • Protein Spikes: Help attach to host cells.

    • Membrane Envelope: Not always present, protects the virus.

VIRAL INFECTIONS

  • Viruses are smaller than cells and require host machinery to replicate.

HOW DO VIRUSES REPLICATE?

  • Virus injects genetic material into a host cell.

  • Host cell fills with virus copies until it bursts, releasing new viruses into the bloodstream.

DISEASES CAUSED BY VIRUSES

  • Measles: Transmitted by air droplets; causes fever and rash.

  • Human Papillomavirus (HPV): Can cause warts and some cancers; many types exist.

  • Flu (Influenza): Common respiratory illness with symptoms like fever and sore throat.

  • Hepatitis: Inflammation of the liver; can be acute or chronic and transmitted person-to-person.

PARASITES

  • Definition: Organisms that use bodies of other organisms to live and reproduce.

  • Types include:

    • Helminths (worms)

    • Protozoa (single-celled organisms)

PROTISTS

  • Definition: Diverse species not classified as plants, animals, fungi, or bacteria.

  • Characteristics:

    • Can be unicellular or multicellular.

    • Contain a nucleus and can move with appendages.

  • Examples: Euglena, Paramecium, Amoeba

DISEASES CAUSED BY PROTISTS

  • Malaria: Transmitted by female mosquitoes carrying Plasmodium; symptoms include fever and chills.

  • Giardiasis: Caused by Giardia lamblia, transmitted through contaminated water or food.

TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES (TSE)

  • Definition: Caused by prions—faulty proteins that induce other proteins to malfunction.

  • Result: Build-up of these faulty proteins can lead to serious illness.

SPREAD OF INFECTIOUS DISEASES

  • Indirect Contact: Exposure to pathogens via contaminated surfaces, food, soil, or air.

  • Vector: Organisms like mosquitos and ticks spreading diseases.

  • Direct Contact: Interaction with infected individuals through blood or bodily fluids.

  • Inhalation: Microorganisms passed through the air.

  • Consumption: Microorganisms passed through food or drink.