RGI 3

Respiratory Processes

  • Breathing Mechanics

    • External Respiration: Process of oxygen transfer from air to bodily tissues.

    • Gas Transport: Occurs in the blood, transporting oxygen and carbon dioxide.

    • Internal Respiration: Oxygen crosses capillaries into body tissues; carbon dioxide is collected and sent to the heart.

Respiratory Anatomy

  • Upper Respiratory Tract

    • Nasal Cavity: Connects to pharynx (space behind the nose and mouth).

    • Larynx: Known as the voice box; positioned below pharynx.

    • Trachea: Located below the larynx.

    • Bronchi: The trachea splits into left and right primary bronchi.

      • Secondary Bronchi: Lead to different lung lobes.

      • Tertiary Bronchi: Further divide into segments of the lungs.

      • Bronchioles: Small airways that distribute air within the lungs.

Respiratory Infections

  • Common Conditions: Upper and lower respiratory tract infections.

    • Upper Respiratory Infections: Generally mild; includes colds caused by rhinovirus or coronaviruses.

    • Lower Respiratory Infections: More severe; can lead to bronchitis or pneumonia due to viruses like influenza and RSV.

Alveolar Structure

  • Alveoli: Gas exchange units of the lungs.

    • Type I Pneumocytes: Comprise 95% of alveolar cells; responsible for gas exchange.

    • Type II Pneumocytes: About 5%; produce surfactant to reduce surface tension and prevent alveolar collapse.

Lung Anatomy

  • Thoracic Cavity Structure:

    • Right Lung: Has three lobes, while the left has two (due to heart positioning).

    • Cardiac Notch: Space in left lung for heart.

Pressure and Breathing Mechanism

  • Pleural Pressure: The pressure in the pleural space is always negative relative to atmospheric pressure, aiding lung inflation.

  • Inspiration:

    • Active Process: Requires muscle contractions (diaphragm and external intercostals) to increase thoracic cavity volume, reducing pressure and drawing air in.

  • Exhalation: Generally passive due to elastic recoil of lungs; elastic forces return diaphragm and rib cage to rest position.

  • Forced Exhalation: Involves muscle contractions (internal intercostals, abdominal muscles) during strenuous activity, pushing air out forcefully.

Respiratory Distress Syndrome

  • Affects premature babies; difficulty inflating alveoli leading to atelectasis (collapsed alveoli).

  • Surfactant: Necessary for lung inflation; without it, respiratory distress occurs.