BIO 132 – Anatomy and Physiology II
Study Outline
9.1. Boyle’s Law:
a. According to Boyle’s Law, for a closed container at constant temperature, a decrease in the volume of the container will result in a(n) ______________________________ in pressure. Conversely, an increase in volume will result in a ________________________________ in pressure.
b. Applied to the lung, inspiration involves reducing alveolar pressure to ________________________________ pressures. This is accomplished by increasing alveolar _____________________________________.
c. Alveoli don’t expand on their own but instead only in response to forces acting on them, in this case supplied by ___________________________.
9.2. Muscles of Respiration:
a. The main muscle of inspiration is the ____________________________ which when contracted increases ____________________________ volume.
b. The other muscles of inspiration are the _____________________________ which _________________________ and _____________________ the ribs.
c. During quiet breathing, expiration is ________________________________.
d. Active (forced) expiration involves the _______________________ muscles and the _______________________________; the latter depress the ribcage ________________________________.
9.3. Events within the Alveolus:
a. Alveoli expand in response to a ____________________________ pressure that acts across their walls.
b. The transmural pressure gradient is determined from the ___________________________________________ minus the ___________________________________________.
c. Even at end-expiration, the intrapleural pressure is _____________________, due to the interaction between the _______________________________ and ___________________________________.
d. At end-expiration, the inward ______________________________ is equal in magnitude to the outward ________________________________. Alveolar pressure is equal to ____________________________ and there is no airflow.
e. At end-expiration, if the intrapleural pressure is –5 cmH2O, then the transmural gradient is equal to ____________________________________.
f. During inspiration, the muscles of inspiration contract which makes the ____________________________ volume larger. This in turn increases the ___________________________ gradient and alveoli expand. At this point, alveolar pressure is ______________________________ than atmospheric.
g. During inspiration, the outward elastic recoil of the chest wall is ________________________________ and the inward elastic recoil of the lung is __________________________________ relative to end-expiration.
h. During expiration, the inward elastic recoil of the lung causes alveolar volume to _____________________________ which raises ____________________ pressure above atmospheric.
i. During expiration, airflow continues until alveolar pressure is equal to ______________________________.
9.4. Compliance of the Lung:
a. Compliance is defined as the _______________________________ over the __________________________________. Lungs with high compliance have ________________________________ slopes on the pressure-volume curve.
b. Restrictive lung diseases like fibrosis involve a ________________________ in lung compliance. The elastic recoil of these lungs are __________________________________________ than a normal lung.
c. Obstructive lung diseases like emphysema involve a ____________________ in lung compliance. The elastic recoil of these lungs are ________________________________________ than a normal lung.
9.5. Surfactant:
a. Surface tension forces arise because the forces between molecules of a liquid are stronger than those between the _____________________________ and the __________________________________. Surface tension forces _____________________________ the elastic recoil of the lung and therefore ____________________________________ the compliance.
b. Surface tension forces are reduced by the presence of __________________ secreted by ________________________________ cells within the alveolus.
c. Surfactant secretion is not fully functional until the 7th month in utero so that premature infants have difficulty expanding their lungs in a condition called _______________________________ syndrome. In adults, a lack of surfactant is called ____________________________________ syndrome.
9.6. Interaction of the Lung and Chest Wall:
a. To function normally the inward elastic recoil of alveoli must be opposed by the ____________________________________ of the chest wall.
b. During a pneumothorax, the chest wall moves _________________________ and the lungs _______________________.
9.7. Airways Resistance:
a. The magnitude of airflow depends on the ratio of the pressure gradient to the _________________________________.
b. As the airway radius increases, the resistance _________________________.
c. In the lower airways, most airways resistance is found in the ________________________. Because the smallest airways are arranged in _________________________________, their total resistance to airflow is _________________________________.
d. Contraction of smooth muscle surrounding airways will _________________ airways resistance.
e. Stimulation of sympathetic nerves leads to a(n) _______________________ in airways resistance, whereas stimulation of parasympathetic nerves leads to a(n) __________________ in airways resistance.
f. You would want to administer ____________________ to a person suffering from an asthma attack.
9.8. Lung Volumes and Capacities:
a. A __________________________ is a device for measuring lung volumes. But it can only measure those volumes that the subject can exchange with it. This does not include the ____________________________________, _______________________________, and __________________________.
b. The volume of air entering or leaving the nose or mouth per breath is called the ____________________________________.
c. The volume of gas inhaled during a normal maximal forced inspiration that begins at the end of a tidal inspiration is called the _______________________________________.
d. The volume of gas expelled from the lungs during a maximal forced expiration that starts at the end of a tidal expiration is called the ________________________________________.
e. The volume of gas left in the lungs after a maximal forced expiration is called the _____________________________________.
f. The volume of gas remaining in the lungs at the end of a normal tidal expiration is called the ____________________________________.
g. The volume of air inhaled into the lungs during a maximal inspiratory effort that begins at the end of a normal tidal expiration is called the _______________________________________.
h. The volume of air expelled from the lungs during a maximal forced inspiration is called the ________________________________________.
i. The volume of air in the lungs after a maximal inspiratory effort is called the _____________________________________________.
j. Restrictive diseases tend to ______________________ lung volumes whereas obstructive disease tend to _____________________________ lung volumes.
9.9. Alveolar Ventilation:
a. The volume of air that enters and leaves the nose per minute is called the ___________________________________.
b. The alveolar ventilation does not equal the minute volume because of the ____________________________________.
c. Thus the alveolar ventilation is equal to the ________________________ minus the ________________________.
d. The most effective way to increase alveolar ventilation for a given minute ventilation is to increase the ______________________________.