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Respiration Organization of Respiratory System. Week 1 Dr. Walid Daoud A. Professor. Organization of Respiratory System. External respiration: Gas exchange of O 2 and CO 2 at level of the lungs between the alveoli and the blood . Internal respiration:
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RespirationOrganization of Respiratory System Week 1 Dr. Walid Daoud A. Professor
Organization of Respiratory System External respiration: Gas exchange of O2 and CO2 at level of the lungs between the alveoli and the blood. Internal respiration: Gas exchange of O2 and CO2 at level of the tissue (mitochondria) and capillaries.
External respiration 1. Pulmonary ventilation. 2. Diffusion. 3. Perfusion: transport of O2 & CO2 in blood. 4. Exchange of O2 & CO2 between blood & tissues by diffusion.
The airway and blood vessels Stimulation of vagus (cholinergic) produces bronchoconstriction. Stimulation of sympathetic (adrenergic) NS produces bronchodilatation. Divisions of airway beyond the larynx: 1. The conducting zone. 2. The respiratory zone.
The conducting zone Functions: 1. Warming & humidification of inspired air. 2. Distributing air to gas exchange areas of lung. 3. Serving as part of body defense system; mucociliary transport system: - Mucus escalator. - Phagocytosis by macrophages.
The respiratory zone It is the site of gas exchange • Respiratory bronchioles • Alveolar ducts • Alveoli • Alveolar sacs
Alveolar structure Type I alveolar cells (Type I pneumocytes) Single layer of epithelial cells lining the wall of alveolus and overlying the basement membrane. Together, the capillary wall and alveolar wall form the respiratory membrane which separates air from blood. Type II alveolar cells (Type II pneumocytes) Produce surfactant. Alveolar macrophages: for phagocytosis.
Lungs and chest wall Chest wall is composed of structures that protect the lungs. Rib cage: 12 pairs of ribs, sternum, thoracic vertebrae and muscles of chest wall: . External intercostal muscles . Internal intercostal muscles . Diaphragm Pleural sac between lung anf chest wall.