Respiratory System Four processes of Respiration 1. Breathing- air in and out of the lungs 2. External respiration- exchange of gases between inhaled air and blood 3. Internal respiration- exchange of gases between blood and tissue fluids 4. Cellular respiration- using oxygen to produce energy within cells, also produces carbon dioxide Figure 10.1 Figure 10.2 Nose Inhale through the nose Receptors in the nose give you sense of smell Nose hair partially filters the air Epithelial tissue lining nasal cavity Lots of blood vessels- warms air Mucus humidifies the air and traps particles Lined with cilia that sweep mucus back where it is either coughed our or swallowed Why does your nose run when it is cold? Cilia lining nasal cavity cells slow down when it is cold Allows mucus to build up and drip out Why does your nose run when you cry? Tear ducts that carry fluid away from your eyes drain into the nasal cavity Pharynx Upper pharynx goes from nasal cavity to the roof of the mouth Two auditory (or Eustachian) tubes connect the ears to the upper pharynx Drain middle ear cavities Equalize air pressure between middle ear and outside air Lower pharynx is the common passageway for food and air Figure 10.3 Larynx Also called voice box Maintains open airway Routes food and air Sound protection Contains epiglottis and vocal cords Epiglottis Flexible flap of cartilage at the opening of the larynx Normally open to allow air in and out Closes as part of the swallowing reflex Blocks airway so that food goes down the esophagus Vocal Cords Two folds of connective tissue surrounding the airway Tone of sound we produce is controlled by how tightly the vocal cords are stretched across the opening Stretching is controlled by skeletal muscle Figure 10.4 Sound Men tend to have deeper voices because their larynx is larger We control pitch by adjusting tension on vocal cords Factors in our unique voices include size and shape or vocal cords, pharynx, nasal cavity, tongue, teeth Muscles in the pharynx, tongue, palate and lips help determine our sounds as well Trachea Windpipe C-shaped, incomplete rings of cartilage- keeps trachea open and allows for changes in diameter Lined with cilia covered, mucus secreting epithelial cells- moves trapped particles upward Choking Blocked trachea causes choking, triggers the cough reflex Sudden expulsion of air from the lungs to dislodge blockage Abdominal muscles and smooth muscles in the trachea contract, pushing air out more forcefully Heimlich Maneuver Bronchi Trachea branches into two airways called bronchi Bronchi divide into smaller and smaller passageways Smaller passageways without cartilage are called bronchioles Transport, warm, clean, and humidify air Lined with ciliated, mucus secreting epithelial cells Smoking and Cilia Tobacco smoke irritates the respiratory tract, causes increased mucus production Continued smoking damages cilia allowing mucus and debris to accumulate Smoker?s cough- violent cough required to get rid of mucus and debris Mucus pooling increases change of infection, emphysema, and lung cancer Lungs Organs of gas exchange Right lung has three lobes, left lung has two lobes Lobes function fairly independently, can remove a lobe and retain lung function Figure 10.7 Alveoli Lungs are a system of branching airways that end in 300 million tiny air-filled sacs called alveoli Gas exchange happens in alveoli Walls are a simple squamous epithelial tissue Combined surface area of 800 square feet Cells secrete surfactant- protein that reduces surface tension and keeps alveoli open Figure 10.8b Figure 10.8a
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