Flashcards in Exam 1 Deck (614)
with a relaxed diaphragm: lungs=
lungs= elastic force relaxed
chest wall= elastic force relaxed
with inhalation, the diaphragm ______________________________ and the lungs & chest wall __________________.
active muscle contraction
* increase in negative pressure, similar to vacuum
during inspiration the external intercostals:
elevate and therefore increase the volume of the pleural cavities
during inspiration the diaphragm:
depresses the inferior wall of the thoracic cavity and, therefore, increase the volume of the cavities
during expiration the internal intercostals:
compress and lower the ribs and therefore decrease the volume of the pleural cavities
during expiration the abdominals:
compress the abdominal cavity which elevates the abdominal organs and passively elevates the diaphragm and, therefore, decreases the volume of the pleural cavities.
transfer of oxygen from alveolar sacs to pulmonary circulation
what 5 principles is diffusion based on:
1. surface area of alveolar capillary membrane
2. diffusing capacity of alveolar-capillary membrane
3. pulmonary capillary blood volume
4. ventilation / blood volume
5. transit time of blood in alveolar capillary membrane
what does the amount of oxygen that diffuses across alveolar-capillary membrane vary with?
varies directly with size (surface area) and inversely with thickness.
decrease the surface area and increase in thickness -->
decrease in amount of O2 in blood
vent (v) / perf (Q) =
apical low perfusion =
lung base perfusion increased due to gravity
apical alveoli expand fully =
lung base enlarged vessels compress alveoli
what does optimal function of the heart depend on?
synchronized coupling of electrical conduction and mechanical contraction
cardiac output =
-force (inotropic effect) & rate of contraction (chronological effect)
what are two measures of myocardial impairment?
large vessels =
elastic & connective tissue
medium to small vessels =
more smooth muscle
what do arteriolar regulate blood flow through?
regional vascular beds
(hydrostatic = out , oncotic = in)
O2 diffusion (__________ content to ____________ content) occurs quickly
intravenous at PO2 averages ____mm Hg
Only _____mmHg pressure needed for cell metabolism
OER: amount of O2 extracted at _______ = 23%
rate of O2 extraction regulated by oxygen ___________ (not oxygen availability)
partially desaturated blood and CO2 are removed from:
cells to venous circulation
what are factors that "shake up" O2 transport
normal: activity, position, emotional stress
disease: bed rest, fever, disease itself, inflammation process, medication, fluid imbalance
what is the greatest influence on O2 transport?
humans are designed to function:
60% of body weight is fluid so...:
small shifts in Gravity --> big fluid shifts