| A | B | 
| where air enters the nasal cavities | nares or nostrils | 
| divides the nasal cavities into halves | septum | 
| functions of the nasal cavity mucosa | warm, filter, humidify | 
| mucous-membrane-lined cavities of the skull | sinuses | 
| functions of the sinuses | 1) reduce skull weight  2) resonate voice | 
| passageway common to the digestive & respiratory systems; the throat | pharynx | 
| below the pharynx; branches into the bronchi; windpipe | trachea | 
| clusters of lymphatic tissue found in the pharynx; aid in the body's defense system | tonsils | 
| re-enforce the trachea & prevent it from collapsing | cartilage rings | 
| voice box | larynx | 
| elastic fibrous tissue that vibrates with exhaled air and allow speech | vocal cords | 
| smallest respiratory passageways | bronchioles | 
| food passageway posterior to the trachea | esophagus | 
| closes off the larynx during swallowing | epiglottis | 
| numerous to increase the amount of gass exchange | alveoli | 
| pleural layer covering the thorax walls | parietal pleura | 
| pleural layer covering the lungs | visceral pleura | 
| autonomic nervous system nerve serving the thorax | vagus | 
| fleshy lobes in the nasal cavity which increase its surface area | conchae | 
| period of breathing when air enters the lungs | inspiration | 
| network of capillaries over the alveoli | respiratory membrane | 
| mucus layer over cilia that line the passages of the lungs | respiratory mucosa | 
| period of breathing when air exits the lungs | expiration | 
| alternate flushing of air into and out of the lungs | ventilation (breathing) | 
| exchange of gases between  capillary blood and cells | internal respiration | 
| exchange of gases between alveolar air and pulmonary capillary blood | external respiration | 
| painful or labored breathing | dyspnea | 
| loss of elasticity of the alveolar sacs; cannot rid themselves of carbon dioxide | emphysema | 
| respiratory passageways narrowed by bronchiolar spasms | asthma | 
| sudden inspiration resulting from spasms of the diaphragm | hiccup | 
| deep breath taken, air forced out; clears lower respiratory passageways | cough | 
| deep breath taken, air forced out; clears upper respiratory passageways | sneeze | 
| increases ventilation of the lungs; believed to be initiated by a need to increase oxygen levels in the blood | yawn | 
| bacterium infction that destroys lung tissue and replaces it with fibrous tissue | tuberculosis | 
| collapsed alveoli in a newborn due to insufficient surfactant | RDS | 
| death of an infant that may have an upper respiratory infection; silent but lethal episode | SIDS | 
| rhinovirus that causes excessive nasal secretion, congestion and sneezing | flu | 
| respiratory volume inhaled or exhaled during normal breathing | tidal volume | 
| total amount of exchangeable air | vital capacity | 
| amount of air that cannot be forced from the lungs | residual volume | 
| amount of air that can be exhaled forcibly after a normal exhalation | expiratory reserve volume | 
| amount of air that can be inhaled forcibly after a normal exhalation | expiratory reserve volume | 
| means of gas exchange at the lungs or body cells | diffusion | 
| direction of movement of gases in diffusion | from higher to lower concentration | 
| movement of carbon dioxide in the body | from tissue cells to capillary blood to alveolar air | 
| direction of movement of oxygen in the body | from alveoli air to capillary blood to tissue cells | 
| blood poor in carbon dioxide and rich in oxygen | arterial blood | 
| blood rich in carbon dioxide but poor in oxygen | venous blood | 
| causes an increased use of the inspiratory and expiratory reserve volumes | exercise | 
| thorax & lung volume during diaphragm contraction | increases | 
| thorax pressure during diaphragm contraction | decreases | 
| direction of air flow during diaphragm contraction | in | 
| direction of rib movement during diaphragm contraction | out | 
| extra credit codeword | Merry Christmas |