Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 16 The Respiratory System UPPER RESPIRATORY TRACT
Document related concepts
no text concepts found
Transcript
Chapter 16 The Respiratory System UPPER RESPIRATORY TRACT Nose • Nasal septum • Nares • Frontal, maxillary, sphenoidal, and ethmoidal sinuses drain into nose • Warms and moistens inhaled air • Contains sense organs of smell Pharynx • • • • • aka throat 3 sections Plays a role with respiration and digestion Passageway for food and liquids Passageway for air Larynx • Cartilage forms framework • Thyroid cartilage (Adam’s apple) is largest • Epiglottis partially covers opening into larynx • Vocal cords stretch across interior of larynx • Passageway for air to move to and from lungs • Voice production LOWER RESPIRATORY TRACT Trachea (Windpipe) • Extends from larynx to thoracic cavity • C-shaped rings of cartilage hold trachea open • Provides passageway for air to move to and from lungs Right and Left Bronchi Bronchioles Alveoli • Microscopic sacs • Surrounded by capillaries • Exchange gases between blood and lungs Respiratory Mucosa • Specialized membrane that lines respiratory tree • Serves as a filter by trapping inspired irritants such as dust and pollen • Upward movement of cilia helps remove trapped irritants Lungs • • • • Apex—narrow upper part Base—broad lower part Right larger than left Divided into lobes – Right upper, middle, lower – Left upper, lower • Function: pulmonary ventilation Pleura • Moist membrane that lines chest cavity and covers outer surface of lungs • Reduces friction MECHANICS OF BREATHING Respiration • Two phases – inspiration – expiration (movement of air out of lungs) • Changes in air pressure cause air to move into and out of the lungs Inspiration • Active process • Diaphragm and external intercostals contract • Thoracic cavity enlarges • Pressure in thoracic cavity is less than that of the atmosphere • Air rushes in Expiration • Ordinarily a passive process • Diaphragm and external intercostals relax • Pressure in thoracic cavity greater than that of the atmosphere • Air is “pushed” out of lungs by pressure Gas Exchange • Carbon dioxide moves out blood into alveoli and out of body in expired air • Oxygen moves from alveoli into blood Volumes • • • • Measured with a spirometer Tidal volume (TV)— normally breath Vital capacity (VC)—forced expiration Expiratory reserve volume (ERV)— what is left after forced expiration • Inspiratory reserve volume (IRV)— forcibly inhaled after a normal inspiration • Residual volume (RV)— air that remains in the lungs after the most forceful expiration Respiratory Rate Usually about 12 to 18 breaths/minute Regulation of Respiration Located in respiratory center of the medulla oblongata
