Class Notes (838,818)
Canada (511,110)
Brock University (12,137)
Biology (1,633)
BIOL 2P93 (93)

Dynamic Lung Mechanics

2 Pages
Unlock Document

Jenny Janke

Mechanics II—Dynamics I. Basic Principles a. Dynamics—concerned w/ bulk airflow occurring predominantly in conducting zone b. Since cross-sectional area of conducting zone is much less than respiratory zone, airflow velocity & resistance ↑ c. Must have pressure gradient for flow to take place: P1-P2 = Q*R = flow*resist. 8μL R = π(r)4 II. Respiratory Muscles a. Inspiratory—contraction => outward movement of chest wall & (-) pressure inside lungs => air flows in i. Normal P = -100 cmH2O insp ii. Diaphragm—major inspiratory mm. iii. Intercostals & accessory mm also help under stress b. Expiratory—normally passive, only use mm. to expel things (cough) & when in extreme states (aggressive exercise) i. Max exp. Pressure > +100cm H2O ii. Max flow limited more by lung factors than by mm. strength iii. Abdominal mm—major expiratory mm III. Quiet breathing a. Always begins & ends at FRC b. Defined as active mm contraction causing inspiration & passive exhalation c. Process i. From FRC, contraction of diaphragm => outward movement of CW ii. Ppl => PA↓ (<0) & air flows into lungs iii. Lung volume increases iv. Inspiratory mm relax => net recoil force v. P A 0 => expiration vi. Continues until FRC d. Ventilation below FRC requires active contraction of expiratory mm. to ↑P >A IV. Airway Resistance a. Airways = tubes in series => resistance falls w/ successive branching b/c ↑ b. Change i. Active—smooth mm. contraction ii. Passive—↑ lung volume => ↑ radius of airways & ↓resistance c. Relationship between airway conductance & lung volume is linear V. Forced Expiration a. Used to asses mechanics & dynamics of airflow b. Spirometry—inhale to TLC then forcibly exhale to RV i. VC—total exhaled volume (vital capacity) ii. FEV1—volume of air exhaled in 1 second iii. FVC—forced vital cap
More Less

Related notes for BIOL 2P93

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.