Respiratory System

1. Respiratory System

2. Functions of the Respiratory System • Pulmonary ventilation – movement of gases into/out of lungs for exchange • Gas conditioning • Sound production • Olfaction • Defense

3. Divisions of the Respiratory System • Structurally divided into: upper and lower respiratory tracts • Functionally divided into: • Conductingportion • Respiratory portions

4. Upper Respiratory Tract • Nose and nasal cavities • Nasal conchae – condition air • Paranasal sinuses • Pharynx • Nasopharynx contains: • Opening of eustachian tube • Pharyngeal tonsil • Oropharynx contains: • Palatine tonsils • Lingual tonsils • Laryngopharynx • All arepart of conducting portion

5. Lower Respiratory Tract • Conducting portion • Larynx • Trachea • Bronchi • Bronchioles • Respiratory portion • Respiratory bronchioles • Alveolar ducts • Alveoli

6. Larynx • Connects pharynx to trachea • Three major cartilages: • Thyroid cartilage • Cricoid cartilage • Epiglottis • Covers opening to airway when swallowing

7. Larynx • Arytenoid cartilages - important in sound production

8. Sound Production • vocal ligaments • covered by mucous membrane • Ligaments + membrane = vocal folds (“true” vocal cords) • vestibular ligaments • Vestibular folds (“false” vocal cords) • Opening between vocal folds - rima glottidis • vocal folds + rima glottidis = glottis • Air forced thru rima glottidis  vibration of vocal folds  sound • Muscles pivot arytenoid cartilages – abduct or adduct folds • Vocal folds in action

9. Trachea • Supported by C-shaped tracheal cartilages • Keep airway open • Posteriorly, connected by trachealis muscle • Lined with PSCC and goblet cells trachealis

10. Bronchial Tree • primary bronchi secondary bronchi tertiary bronchi • All bronchi lined with PSCC • Rings of cartilage get smaller and smaller • Bronchi  bronchioles • < 1 mm diameter • No cartilage • Lining simple ciliated columnar  cuboidal

11. Bronchioles • Walls composed of relatively thick layer of smooth muscle • Allows for bronchoconstriction/dilation • Bronchioles  terminal bronchioles • last part of conducting portion • Terminal bronchioles  respiratory bronchioles  alveolar ducts  alveoli • Primary location of gas exchange between blood and air • Surface area of each lung is approx. half a tennis court

12. Alveoli • Alveolar type I cells – simple squamous ET • rapid diffusion of gases • Alveolar type II cells • produce pulmonary surfactant • decreases surface tension w/in alveolus • prevents collapse of alveoli

13. Alveolar Macrophages • Third type of cell, alveolar macrophage (dust cell) • engulfs microorganisms or particulate matter

14. Lungs and Pleura • Lungs located in pleural cavities • serous membrane called pleura • Visceral pleura • Parietal pleura

15. Left Lung • Slightly smaller than right lung • b/c of heart • cardiac notch • Oblique fissure divides lung into superior and inferior lobes

16. Right Lung • oblique and horizontal fissures • divide lung into superior, middle and inferior lobes

17. Thoracic Wall Dimensional Changes During Respiration • Vertical – movement of diaphragm • Lateral – muscles attached to ribs • Anterior/Posterior – muscles attached to ribs • Expansion of cavity  inhalation • Compression of cavity  exhalation

18. Muscles Attached to Ribs • Muscles attached to ribs: • Scalenes (inhalation) • Elevate ribs 1 &2 • External intercostal (inhalation) • Elevate ribs • Internal intercostal (forced exhalation) • Depress ribs

19. Respiratory Control Centersin the Brainstem • Respiratory rhythmicity center in medulla oblongata • controls rate and depth of breathing • Dorsal respiratory group (DRG) • stimulates muscles of inspiration • Ventral respiratory group (VRG) • controls forced exhalation • Inactive during normal breathing

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