Study Guides (238,455)
United States (119,809)
Physiology (48)
PSIO 420 (4)

Review Exam 3 PSIO 420.docx

4 Pages
Unlock Document

University of Arizona
PSIO 420
Douglas Keen

Review Exam 3 PSIO 420 Respiratory purposes: Ventilation - moving air in and out of the lungs which allows for external respiration pH regulation - removal of CO2 and how it contributes to acid/base balance Respiration: External vs. Internal • External - diffusion of gasses from tissues to blood in the lungs. • Internal - Diffusion of gasses from blood to tissues in the muscles, skin, organs Well why do we breath?? - we do it to get gas exchange so that aerobic respiration can be performed. This exchange is called diffusion of gasses. KEY POINT: Respiratory system is not limiting factor during exercise!! Family tree of AIR way: The last section is alveoli - 24 - Diameter decreases as you move from top to bottom. - Length also decreases moving from top to bottom, with the alveoli being 1/3 mm. - The number of each increased moving from top to bottom, causing the number of alveoli to be about 300 million. - Lastly total cross sectional area decreased from 0 to 3, however increased from 3 to 24. The alveoli was about 50 -100m in total cross sectional area. - The conducting zone is also called anatomical dead space, due to no gas diffusion in this area. Anatomy of Lungs: Function is to help expand and relax the lungs, inhale and exhale. - Visceral pleura is outer layer on the lungs. -Parietal pleura is attached to the chest wall. -Pleural cavity is the space in-between the visceral pleura and parietal pleura. - Alveoli sac • very well vascularized • Large surface area for gas exchange • Very thin respiratory membrane: Has to cross three barriers  Alveolar cell membrane (Type 1 alveolar cell simple squamous) - epithelial basement membrane  Interstitial space  Capillary (endothelial cell) - also a basement membrane • Type II cells - secrete surfactant (3%)  allows for alveoli so expand - no collapsing  There is also a thin layer of water present in the alveoli which causes the cell to want to collapse, surfactant stops this from happening. Gas diffusion: • Velocity of gas diffusion is proportional to the AREA, D is a constant, and Driving pressure(P1-P2) and is inversely proportional to Thickness • Thickness is proportional to Solubility and inversely proportional to square root of Molecular Weight Lecture 18: part 2 Mechanics of Breathing - Change in volume to effect pressure: The diaphragm, intercostal muscles, and accessory muscles change volume that ultimately changes pressure. KEY POINTS: • Air moves from areas of high pressure to areas of low pressure. • Boyle's Law - Volume and pressure are inversely proportional - first change volume to change pressure. • Inspiration - takes place when alveolar pressure is lower than the outside pressure (this only takes a couple of mm of Hg) • Expiration - Takes place when alveolar pressure is higher than the atmospheric pressure outside the body.
More Less

Related notes for PSIO 420

Log In


Don't have an account?

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.