Overview of the Human Respiratory System

Sep 10, 2024

Lecture on the Human Respiratory System

Introduction

  • Human respiratory system allows gas exchange (oxygen intake, carbon dioxide expulsion).
  • Not to be confused with cellular respiration (process inside cells to produce ATP).

Pathway of Air

  • Inhalation: Air enters nasal cavity.
    • Air is warmed, humidified, filtered (via mucus and nasal hairs).
  • Pharynx: Junction for food and air.
  • Larynx: Known as the voice box.
  • Trachea: Tube supported by cartilage rings, leading to lungs.
  • Bronchi and Bronchioles:
    • Trachea divides into primary bronchi (one for each lung).
    • Further divides into secondary and tertiary bronchi, then into bronchioles.
    • Resembles an upside-down tree.
  • Alveoli:
    • Located at the end of bronchioles.
    • Alveoli clusters (alveolar sacs) serve as site for gas exchange.
    • Surrounded by capillaries for oxygen uptake and carbon dioxide removal.

Lungs Structure

  • Two lungs: Right lung (3 lobes), Left lung (2 lobes, has cardiac notch).
  • Left lung is smaller due to space for the heart.

Respiratory and Other Systems

  • Circulatory System:
    • Works with respiratory system to transport gases.
  • Skeletal and Muscular Systems:
    • Ribs protect lungs; intercostal muscles, diaphragm, and abdominal muscles aid in breathing.
  • Nervous System:
    • Regulates involuntary breathing using blood pH as a feedback mechanism.

Breathing Regulation

  • Increase in CO2 leads to increased H+ in blood, lowering pH (more acidic).
  • Brain detects acidity and adjusts breathing rate/depth to stabilize pH.
  • Maintains homeostasis (blood pH ~7.4).

Comparative Respiratory Systems

  • Different organisms have unique systems:
    • Earthworms: Gas exchange through skin.
    • Fish: Use gills.
    • Insects: Tracheal system with spiracles.

Respiratory Health and Careers

  • Understanding helps treat respiratory illnesses (e.g., asthma, emphysema).
  • Careers: Pulmonologists, respiratory therapists.

Surfactant and Premature Babies

  • Alveoli require surfactant to prevent collapse (reduces water surface tension).
  • Premature babies may lack sufficient surfactant, causing respiratory distress syndrome.
  • Treatment with artificial surfactants can save lives.

Remember to review properties of surfactants and how they function in respiratory health.

Conclusion

  • Respiratory system is crucial for life and intricately connected with other body systems.
  • Stay curious and keep exploring more about how our bodies work.

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