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THE RESPIRATORY SYSTEM. RESPIRATION. The exchange of gases between the atmosphere, lungs, blood, and tissues. Respiration. Pulmonary ventilation: “breathing” External respiration: occurs within the lungs Transport of respiratory gases: via the blood
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RESPIRATION The exchange of gases between the atmosphere, lungs, blood, and tissues
Respiration • Pulmonary ventilation: “breathing” • External respiration: occurs within the lungs • Transport of respiratory gases: via the blood • Internal respiration: occurs within the tissues
REQUIREMENTS • Gas exchange surfaces must be thin. • Gas exchange surfaces must remain moist. • Gas exchange surfaces must be large in relation to the size of the organism.
FUNCTIONAL ANATOMY - Upper respiratory • Nose • Pharynx - Lower respiratory • Larynx • Trachea • Bronchial tree • Lungs • Diaphragm
Features of the Nose • External Nares: • The nostrils where air enters the nasal cavity • Nasal Septum: • Divides the nasal cavity into two symmetrical halves • Olfactory/Respiratory Mucosa: • Contain smell receptors and goblet cells for mucus secretion
Features of the Pharynx • Nasopharynx: • Acts only as an air passageway; when swallowing, uvula and soft palate close it off • Location of pharyngeal tonsil • Eustachian tubes • Oropharynx: (fauces) • Common passageway for food and air • Location of palatine and lingual tonsils • Laryngopharynx: (hypopharynx) • Common passageway for food and air • Intersects with trachea; location of epiglottis
Features of the Larynx • Three functions • Provides an open airway • Routes food and air into proper tubes (epiglottis) • Voice production (vocal folds) • Several cartilages located here (thyroid, cricoid, and arytenoid) • Epiglottis: • Flap of elastic cartilage that shuts off larynx and trachea from incoming food (only works in conscious people) • Vocal Folds: • True vocal cords that vibrate with air coming up from the lungs. Space between is called the rima glottidis • Vestibular folds (false vocal cords)
Features of the Trachea • Contains mucosa • Goblet cells produce mucus • Cilia of pseudostratified columnar epithelium propel debris-laden mucus to pharynx • Contains C-shaped cartilage • Helps the trachea to expand and recoil • Prevents trachea from collapsing despite pressure changes that occur during breathing
Features of the Bronchial Tree • Primary Bronchi: • Runs obliquely into mediastinum and enters lung at lung hilus; two primary bronchi emerge from trachea. Right bronchi is larger, shorter and oblique. Aspiration. Bifurcation is called the carina. • Secondary Bronchi: • Each primary divides into secondary (3 on right and 2 on left) bronchi that service each lung • Tertiary Bronchi: • Secondary bronchi branch into tertiary which branch into smaller and smaller tubes • Bronchioles: • Tiniest of tertiary bronchi, less than 0.5 mm in diameter; smallest are terminal bronchi
Bronchoscope: illuminated, tubular instrument to view bronchi and trachea. • Bronchography: technique used to examine the bronchial tree. A catheter (intratracheal) is passed through the nose or mouth and through the rima glottidis into the trachea. A contrast, usually containing iodine, is inhaled and an x-ray is taken called a bronchogram.
Features of the Lower Bronchial Tree • Terminal Bronchioles: • The smallest bronchioles that feed directly into: • Respiratory Bronchioles: • Feed into each lung which lead into: • Alveolar ducts: • Contain rings of smooth muscle and alveoli which is the structure gases are exchanged in. • Contain a chemical called surfactant which reduces surface tension
Lungs - right and left - Lungs have lobes and fissures - 3 lobes in the rt. lung - superior - middle - inferior - 2 fissures: horizontal and oblique - 2 in the left lung - superior - inferior - cardiac notch for heart to rest in. - 1 fissure: oblique
- Lung has broad inferior surface called the base. - Lung has a pointed superior surface called the apex or the cupola