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RESPIRATORY SYSTEM. FUNCTION. TO MOVE AIR IN AND OUT OF THE LUNGS EXCHANGE OF OXYGEN AND CARBON DIOXIDE BETWEEN THE AIR AND THE BLOOD. DIVISIONS. UPPER RESPIRATORY TRACT – THE PART OUTSIDE THE CHEST CAVITY INCLUDES NOSE, NASAL CAVITIES, PHARYNX, LARYNX, AND UPPER TRACHEA
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FUNCTION • TO MOVE AIR IN AND OUT OF THE LUNGS • EXCHANGE OF OXYGEN AND CARBON DIOXIDE BETWEEN THE AIR AND THE BLOOD
DIVISIONS • UPPER RESPIRATORY TRACT – THE PART OUTSIDE THE CHEST CAVITY • INCLUDES NOSE, NASAL CAVITIES, PHARYNX, LARYNX, AND UPPER TRACHEA • LOWER RESPIRATORY TRACT – THE PART INSIDE THE CHEST CAVITY • INCLUDES LOWER TRACHEA, LUNGS, BRONCHIAL TUBES, AND ALVEOLI
NOSE AND NASAL CAVITIES • AIR ENTERS AND LEAVES THE NOSE • WARMS THE AIR • CONTAINS MUCOUS • HAIRS BLOCK THE ENTRY OF DUST • OLFACTORY RECEPTORS FOR SMELL
PHARYNX – 3 PARTS • NASOPHARYNX – UPPERMOST PORTION BEHIND THE NASAL CAVITIES • ALLOWS PASSAGE OF AIR • OROPHARYNX – BEHIND THE MOUTH • LARYNGOPHARYNX – INFERIOR PORTION • ORO- AND LARYNGOPHARYNX ALLOW THE PASSAGE OF AIR AND FOOD
LARYNX • AKA VOICE BOX • FUNCTIONS IN SPEAKING AND THE AIR PASSAGEWAY BETWEEN THE PHARYNX AND TRACHEA • MADE OF CARTILAGE THAT IS FIRM TO KEEP AIRWAY OPEN YET IT IS FLEXIBLE • THE LARGEST CARTILAGE IS THE THYROID CARTILAGE
EPIGLOTTIS - THE UPPERMOST CARTILAGE • IT CLOSES OVER THE TOP TO PREVENT THE ENTRY OF FOOD IN TO THE LARYNX • MUCOSA IS MADE OF CILIATED EPITHELIUM TO REMOVE DUST AND MUCOUS • VOCALS CORDS ARE ON EITHER SIDE OF THE GLOTTIS
TRACHEA • APPROXIMATELY 4-5 INCHES LONG • EXTENDS FROM LARYNX TO THE PRIMARY BRONCHI • MADE OF CARTILAGE THAT CONSISTS OF CILIATED EPITHELIUM • DIVIDES IN TO RIGHT AND LEFT PRIMARY BRONCHI
BRONCHI • RIGHT AND LEFT PRIMARY BRONCHI • LEADS TO SECONDARY BRONCHI • LEADS TO BRONCHIAL TREES • BRANCHES FURTHER IN TO BRONCHIOLES TO THE ALVEOLI
LUNGS • RIGHT LUNG HAS 3 LOBES • LEFT LUNG HAS 2 LOBES • PROTECTED BY RIBS • BASE OF EACH LUNG RESTS ON THE DIAPHRAGM AND THE APEX IS AT THE CLAVICLE • INDENTATION ON THE MEDIAL SIDE OF LUNGS IS THE HILUS WHERE PRIMARY BRONCHUS AND ARTERIES/VEINS ENTER THE LUNG
PLEURA • PARIETAL PLEURA LINES THE CHEST WALL • VISCERAL PLEURA LIES ON THE SURFACE OF THE LUNGS • SEROUS FLUID BETWEEN THE MEMBRANES PREVENTS FRICTION
ALVEOLI • FUNCTIONAL UNIT OF THE LUNGS • MADE OF SIMPLE SQUAMOUS EPITHELIUM • ELASTIC CONNECTIVE TISSUE BETWEEN CLUSTER OF ALVEOLI WHICH IS IMPORTANT FOR EXHALATION • DIFFUSION OCCURS BETWEEN ALVEOLI AND BLOOD VESSELS • MACROPHAGES ARE IN THE ALVEOLI • PULMONARY SURFACTANT DECREASES SURFACE TENSION AND PERMITS INHALATION
MECHANISM OF BREATHING • VENTILATION – MOVEMENT OF AIR TO AND FROM ALVEOLI • RESPIRATORY CENTERS – MEDULLA (ALSO FOR COUGHING AND SNEEZING) AND PONS (2 BREATHING CENTERS) • PHRENIC NERVE ACTIVATED FROM THE MEDULLA TO CONTRACT AND RELAX THE RESPIRATORY MUSCLES
RESPIRATORY MUSCLES • DIAPHRAGM – MOVES DOWN DURING INHALATION AND UP DURING EXHALATION. MADE OF SKELETAL MUSCLE. • EXTERNAL INTERCOSTAL MUSCLES – PULL THE RIBS UPWARD AND OUTWARD DURING INHALATION • INTERNAL INTERCOSTAL MUSCLES – PULL THE RIBS DOWNWARD AND INWARD DURING EXHALATION
RESPIRATION • INHALATION IS AN ACTIVE PROCESS LASTING 1-2 SECONDS • EXHALATION IS A PASSIVE PROCESS LASTING 2-3 SECONDS • NORMAL RESPIRATIONS ARE 8-12/MIN
RESPIRATION • EXTERNAL RESPIRATION - INVOLVES THE EXCHANGE OF GASES BETWEEN THE ALVEOLI AND THE PULMONARY CAPILLARIES (EXTERNAL ENVIRONMENT) • INTERNAL RESPIRATION – INVOLVES THE EXCHANGE OF GASES BETWEEN THE BLOOD IN THE SYSTEMIC CAPILLARIES AND THE TISSUES
DID YOU KNOW… • WE INHALE APPROX 21% OXYGEN AND 0.04% CARBON DIOXIDE • WE EXHALE APPROX 16% OXYGEN AND 4.5% CARBON DIOXIDE
TRANSPORT OF GASES • MOST OXYGEN IS CARRIED IN THE BLOOD BONDED TO Hgb • IRON IS NECESSARY • GAS EXCHANGE IS CARRIED OUT BY DIFFUSION
PULMONARY VOLUMES • TV – TIDAL VOLUME – AMOUNT OF AIR IN 1 NORMAL INHALATION/EXHALATION (500mL) • MRV – MINUTE RESPIRATORY VOLUME – AMOUNT OF AIR INHALED AND EXHALED IN 1 MINUTE TV x R = MRV (6000 mL or 6 L)
PULMONARY VOLUMES • IR – INSPIRATORY RESERVE – AMOUNT OF AIR, BEYOND THE TV, THAT CAN BE TAKEN IN WITH THE DEEPEST POSSIBLE INHALATION (2000-3000mL) • ER – EXPIRATORY RESERVE – AMOUNT OF AIR, BEYOND THE TV, THAT CAN BE EXPELLED WITH THE MOST FORCEFUL EXPIRATION (1000-1500 mL)
PULMONARY VOLUMES • VC – VITAL CAPACITY – THE SUM OF THE TV, IR, AND ER (3500-5000 mL) • RESIDUAL AIR – THE AMOUNT OF AIR THAT REMAINS IN THE LUNGS AFTER THE MOST FORCEFUL EXHALATION (1000-1500mL) • VOLUMES ARE DETERMINED WITH A SPIROMETER THAT MEASURE THE MOVEMENT OF AIR