2. Respiratory System

3. Functions To provide conducting passageways to allow oxygen to be used in the body to release energy Purifies, humidifies, and warms incoming air Filters out irritants from the air.

5. Nasal Cavity (nose) –Only visible part of the respiratory system –Air enters through external nares (nostrils) divided by nasal septum –Olfactory sensors located at the top near the bridge of the nose –Mucus moved by ciliated cells that move in a wavelike motion toward the throat –Sinuses lighten skull and act as resonance chambers to speech

6. Larynx (voice box) –Contains a pair of membrane form vocal folds –Epiglottis – when swallowing larynx moves up causing epiglottis to cover trachea –Problem – laryngitis – inflammation of larynx (mucosa/vocal cords)

7. Trachea (windpipe) –Has a thick layer of cartilages that descends into the lungs –Splits to form primary bronchi which lead into the lungs Bronchi  broncioles  alveoli –Tracheostomy – surgical procedure that provides an alternate route for air to enter the lungs

8. Lungs –Left has 2 lobes. Right has 3 lobes Left is smaller because heart is in the way –Weights only 2.5 pounds –NOT HOLLOW –Diaphragm – (what allows you to breath) large muscular sheet at base of lungs responsible for volume and pressure changes in lungs

9. Bronchioles –Bronchi split again and again (respiratory tree) –All but smallest branches have reinforcing cartilage (respiratory bronchioles don’t have cartilage) –Heimlich maneuver – used to force air through bronchioles and trachea to dislodge objects

10. Alveoli –Small air sacs, look like a bunch of grapes (alveolar sacs) –Bunches connected by alveolar ducts –Lots of capillaries –Surface area 50-70 m2 40X greater than surface of skin