Respiratory System Biology

Respiratory system outline I.Why need respiration? II.Steps of respiration 1. inhalation 2. cleaning dirty air 3. gas exchange 4. circulation 5. exhalation III.Journey through organs 1. nasal cavity 2. pharynx 3. larynx 4. trachea 5. bronchi 6. bronchioles 7. alveoli IV.Mechanics of breathing Diaphragm Inhale/ exhale

Breathing Gas exchange of oxygen and carbon dioxide Formation of ATP energy within cells

Remember Cellular Respiration Using oxygen to break down glucose and release energy! Without oxygen, not enough energy is obtained from food for survival

Steps of respiration: 1.Inhalation: taking in air (oxygen) 2.Cleaning dirty air: mucus and cilia remove foreign material 3. Gas exchange: oxygen and carbon dioxide cross cell membranes 4.Circulation of gases: through bloodstream to all body parts 5.Exhalation: air (carbon dioxide) leaves body

How air travels through body 1.Nasal cavity –filters, warms, humidifies air (cell membranes must be moist for gases to properly cross) 2.Pharynx (throat)– where paths for air and food cross (epiglottis remains open unless swallowing) 3. Larynx – voicebox

4.Trachea (windpipe)- have rings of cartilage to keep from collapsing 5.Bronchi – two tubes where trachea forks, one leading to each lung

6.Bronchioles – fine tubes that branch from bronchi in each lung 7.Alveoli – grapelike clusters of air sacs where bronchioles dead end * lungs have millions of these tiny sacs where oxygen and carbon dioxide are exchanged by diffusion

Mechanics of breathing: Diaphragm is sheet of muscle underneath chest cavity (lungs) During inhalation, diaphragm contracts and moves downward which creates a vacuum; air rushes into lungs since high air pressure outside and low pressure inside During exhalation, diaphragm relaxes and moves upward, pushing air out of lungs

Respiratory Problems: Hiccups: uncontrolled spasms of the diaphragm; each spasm causes quick intake of breath which produces a sound as it passes your voicebox Hyperventilation: rapidly taking several deep breaths; depletes blood of so much carbon dioxide that breathing centers turn off

Lung cancer: Tobacco smoke and other pollutants irritate the cells lining the bronchi which allows more toxins to enter the lungs’ alveoli Smoking is # 1 cause of lung cancer; smokers typically die years earlier than non-smokers The 5 year survival rate for those diagnosed with lung cancer is 15%; most die within 1 year of diagnosis

162,000 people die in US each year from lung cancer 3,000 people die from secondhand smoke lung cancer asthma: airways become constricted due to triggers such as pets, pollutants, etc.