BIO2215 - Unit 11 - Part 1

Overview of the Respiratory System Infections

  • Transitioning from immunology to microbiology, focusing on infections affecting the respiratory system.
  • Importance of understanding normal flora in the respiratory tract.

Division of the Respiratory Tract

  • Upper Respiratory Tract:

    • Defined as everything from the larynx and above (e.g., sinuses, nasal passages).
    • Host normal flora can vary based on individual factors (e.g., smokers vs. non-smokers).

  • Lower Respiratory Tract:

    • Includes the trachea, bronchi, and lungs (composed of alveoli).
    • Normal flora present, but with variations.

Normal Flora and Infections

  • Normal Flora:
    • Varies among individuals based on health, environment, habits, and biology.
    • Presence can aid in understanding infections.
  • Common Infectious Agents:
    • Staphylococcus aureus, Haemophilus, and Streptococcus can be found throughout the tract.

Types of Infections

  • Upper Respiratory Infections (URI):

    • Generally not life-threatening, includes common colds, sinusitis, otitis media (ear infections), and conjunctivitis (pink eye).
    • Characterized by discomfort, congestion, runny nose, sneezing, etc.

  • Lower Respiratory Infections (LRI):

    • More severe, examples include tuberculosis and pneumonia, potentially fatal if untreated.
    • These infections hinder breathing, a crucial life function.

Anatomy & Physiology Connection

  • The respiratory tract lined by mucous membranes, serving as a first line of defense.
  • Mucus Functionality:
    • Traps inhaled particles, microbes, which can be moved up and out via the mucociliary escalator or swallowed into gastric acid.

Eye and Tear Functions

  • Conjunctiva:
    • Eyes typically lack normal flora; tears play a protective role (antimicrobial components like lysozyme).

Overview of Specific Infections

  • Pink Eye (Conjunctivitis):

    • Symptoms: excessive tearing, swelling, pus.
    • Treatment focuses on antibiotics to prevent vision loss.

  • Sinusitis:

    • Presents as pain and pressure in the sinuses (localized vs. general nasal symptoms).
    • Often requires supportive treatment due to difficulties in eradicating the infection.

  • Otitis Media:

    • Commonly seen in children due to anatomical differences; severe ear pain and potential fever.
    • Pressure causes eardrum bulging; untreated infections can lead to perforation and possible hearing loss.

Common Causative Agents

  • Agents for URI include:
    • Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Staphylococcus aureus.
    • Many are viral in origin, complicating treatment options.