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20 Cards in this Set

  • Front
  • Back
What prevents lungs from collapsing?
The pressue differntial between the intrapleural space and the lungs
negative-pressure breathing
increase in volume reduces intrapleural pressue causing lungs to expand and fill with air in a vaccum-like fashion
external intercostal muscles
- contract during inhalation and pushes rib cage and chest wall up and out
passive process
- decrease in thoracic cavity volume causes air pressue in the interpleural space to increase
internal intercostal muscles
- contract, pulling rib cage down during FORCED exhalation
surrounds alveoli
- reduces high surface tension of fluid lining the alveoli, preventing alveolar collapse during exhalation
medulla oblongata
- respiratory center
- stimulate intercostal uscles or diaphragm to contract
- found in aorta, etc.
- respond to changes in pH and pCO2 in blood stimulating medulla oblongata
Ventiliation is consciously controlled by that part of the brain?
- deep, rapid breathing
- lowers pCO2 in blood below normal
- chemotreceptors sense this and signal medulla oblongata to inhibit breathing
vital capacity
= mad amount of air that can forcibly be inhaled and exhaled from lungs
tidal volume
- amount o fair normally inhaled and exhaled with each breath
residual volume
- air that always remains in lungs, preventing alveoli from collapsing
expiratory reserve volume
- volume of air that can still be forcibly exhaled following normal exhalation
total lung capacity
- equal to the vital capacity + residual volume
In what three ways does the body compensate for high altitudes?
- increase ventilation (hyperventilation)
- increase RBCs (polycythemia)
- decrease affinity of O2 to facilitate unloading of oxygen in the TISSUES
Why is the process of inhalation referred to as negative-pressure breathing?
- expansion of thoracic cavity creates a vacuum, which pulls air into lungs
- contrasts positive-pressure breathing: air is forced into lungs
The lungs can collapse from...
- insufficient surfactant production
- rupture of parietal pleura
What is the function of surfactant, and where is it found?
- Surfactant is secreted by eptithelial cells in lung and coats alveli
- reduces alveolar suface tension
- makes lungs easier to inflate during inhalation
- prevents alveolar collapse during exhalation
Sequence of passages air travels through during inhalation
pharynx --> larynx --> trachea --> bronchi --> alveoli