-
Nasal Cavity
nasal conchae, mucus membranes; intake, purification, hydration and thermoregulation of air entering the respiratory system through the nasopharynx and pharynx
-
Larynx (respiratory tree)
- vocal folds for creation of sound; glottis provides for entrance into respiratory system from pharynx;
- epiglottis closes glottis during swallowing to prevent movement of food and liquid intothe respiratory system;
- cricoid and thyroid cartilages (and others) provide structure for larynx
-
Trachea (respiratory tree)
- tracheal cartilages provide structure to maintain patency (open);
- psudostratified ciliated columnar epithelium with goblet cells provides for purification of air and movement of debris up to pharynx
-
Bronchi (respiratory tree)
- Provide for movement of air into lungs (toward alveoli);
- Surrounded by C-shaped cartilages or (in secondary and tertiary bronchii, cartilage plates) which provide support to prevent collapse;
- ten tertiary bronchii in right lung and about nine in left lung; open into bronchioles
-
Bronchioles (respiratory tree)
- lack cartilagenous support; dominated by smooth muscle capable of bronchodilation (sympathetic activation) or bronchoconstriction (parasympathetic activation);
- terminal bronchioles lead to respiratory bronchioles which lead to alveolar ducts which lead to alveoli
-
Alveoli
Air sacs of the lungs
-
Alveolar Type I cells
Squamous cells forming the wall of alveoli
-
Alveolar Type II cells
surfactant cells produce surfactant (phospholipids) which reduce surface tension within alveoli and prevent collapse of the alveoli
-
Dust cells
Fixed macrophages within the alveoli which phagocytize debris, bacteria, etc
-
Pulmonary arteries (pulomonary blood supply)
Supply deoxygenated blood from right ventricle to blood vessels, ultimately capillaries surrounding alveoli
-
Pulmonary Veins (Pulmonary Blood Supply)
return oxygenated blood from lungs to left atrium of the heart
-
Alveolar capillaries (pulmonary blood supply)
site of external respiration
-
External respiration
- Exchange of oxygen and carbon dioxide between alveoli of lung and blood within capillaries
- Oxygen from alveoli enter blood cells and attach to emoglobin forming oxyhemoglobin; hydrogen ions released from the hemoglobin and reacts with bicarbonate to form carbonic acid; carbonic anhydrase catalyzes breakdown of carbonic acid into carbon dioxide and water; carbon dioxide diffuses from blood cell toward alveolar space where it is exhaled
-
Internal respiration
- exchange of oxygen and carbon dioxide between bloodstream and tissues of the body;
- carbon dioxide from cells enters red blood corpuscles and reacts with water to form carbonic acid; lower pH stimulates release of oxygen from hemoglobin which diffuses into cells (Bohr Effect)
|
|
