Class Notes (835,539)
Canada (509,225)
Physiology (1,062)
Tom Stavraky (262)
Lecture

Ventilation

2 Pages
95 Views
Unlock Document

Department
Physiology
Course
Physiology 3120
Professor
Tom Stavraky
Semester
Winter

Description
Human Physiology Monday, February 1, 2010 “Respiration II” Ventilation • Process by which air moves in and out of the lung • Inspiration/inhalation  Active process; requires contraction of diaphragm muscles and intercostal muscle  Contraction of external intercostals and contraction of diaphragm increases pressure gradient between interpleural space and lungs • Only takes a relatively small change in pressure • Cutting a hole in the diaphragm will interfere with inspiration (interpleural pressure will be atmospheric  Lung inflates because have larger surrounding area • Expiration/exhalation  Passive process normally; lung and chest wall moves back to equilibrium  Active process during exercise or spontaneous hyperventilation; muscles of abdominal wall/internal intercostals; cutting the internal intercostals would prevent voluntary expiration (i.e. won’t be able to exercise) • Lung compliance  Relatively small changes in pressure required to inflate lung  Volume change per unit pressure change  Large = large volume change for small pressure change  Small = small volume change for large pressure change  2 factors  Elasticity of lung tissue • Fibres of elastin (easily stretched) and collagen (not easily stretched) • Specific arrangement of these fibres  Surface tension at alveolar level  Can plot it with a pressure-volume curve  Take lung out, slowly inflate & deflate it and measure the pressure (dog lung)  Initially, you don’t get large increase in volume for a change in pressure; if you continue inflation, get a large volume increase for each pressure interval  Important features: • Nonlinear • At high and low volumes, the lung is less compliant than at intermediate volumes • At the same pressure, the lung has more volume during deflation than during inflation (hysteresis) • Note tha
More Less

Related notes for Physiology 3120

Log In


OR

Join OneClass

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

Sign up

Join to view


OR

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.


Submit