Human Respiration Breakdown of glucose to make energy Exchange of O2 and CO2 across the thin, moist membranes of the lungs (alveoli) Nasal Cavity- air enters, ciliated membranes of nostrils help to clean, warm and moisten the air. Pharynx- Passage between nasal cavity and trachea Larynx- upper end of trachea, voice box with vocal cords

Trachea- takes oxygen to lungs, lined with cartilage, ciliated membranes inside trap particles of food and dust, sweeps upward Epiglottis- prevents food from entering trachea Bronchi- extend from trachea to both lungs, smaller tubes are bronchioles, at the end is a cluster of alveoli,( air sacs surrounded by capillaries)

Gas exchange 02 diffuses into blood at the alveoli and attaches to hemoglobin to diffuse to body cells, CO2 diffuses out of the blood at the alveoli and is carried by a bicarbonate ion

Breathing Inhalation-ribs move up and out, diaphragm moves down, lungs expand Exhalation- ribs move down and in, diaphragm up, lungs contract, air moves out Breathing rate controlled by medulla in brain that senses CO2 in blood (increase CO2, increase breathing)

Disorders Bronchitis- inflammation of bronchioles, due to excess mucus Asthma- allergic reaction, narrowing of bronchiole tube Emphysema- breakdown of alveoli, decreased surface area, due to smoking