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GNUR 293_ Exam 4 (2)
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GNUR 293_ Exam 4 (2)
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GNUR 293: Exam 4Ventilation - ANS-movement of air in and CO2 out of the lungs
ex: decrease ventilation = asthma or obstruction (air in)
Functional residual capacity - ANS-reserve of air that is left over in lungs after expiration
-decrease will occur in COPD, pregnant women, obese patients
-become hypoxic much quicker
Pulmonary function test (PFT) - ANS-evaluation of airflow in lungs
-used spirometer
-obstructive = can't get air out
-restrictive= can't get air in
Ventilation dead space: anatomic dead space - ANS-volume of gas not used in gas
exchange (no perfusion or diffusion-only in lungs)
-apex of lung "dead space"
Mechanics of breathing: airway resistance - ANS--influenced by airway radius and
pattern of gas flow
-stimulation of cholinergic fibers (PNS) = bronchoconstriction
-Stimulation of B2 adrenergic fibers (SNS) = bronchodilation
-turbulent flow increases resistance
-laminar flow decreases resistance
Mechanics of breathing: lung compliance - ANS--influences the work of breathing
-represents lung expandability and ease of lung inflation
ex: skinny jeans/smaller balloon = low/decreased compliance; wide jeans/bigger balloon
= high/increased compliance
Low compliance - ANS--low volume inflation
-high pressure or effort
ex: fibrosis, stiff lung
High compliance - ANS--high volume of inflation
-low pressure or effort
ex: COPD, loss of elastic
Are alveoli larger at base or apex of lung? - ANS-apex
,Perfusion - ANS--movement of blood in and out of capillary beds of lungs to body
organs/tissues
ex: decrease perfusion = pulmonary emboli
Where is perfusion the highest in the lung? - ANS-The bottom or base or zone 3
aka lowest ventilation
-work of breathing is done here
Where is perfusion the lowest in the lung? - ANS-The top or apex or zone 1
aka highest ventilation
What is the ventilation to perfusion ratio? - ANS-0.8
4 L/min of alveolar ventilation to 5 L/min capillary blood flow
Hypoventilation - ANS--insufficient delivery of air to alveoli to meet need to provide O2
and remove CO2
-increase PaCO2 (hypercapnia) due to decrease respiration
causes for hypoventilation - ANS--morphine
-sleep apnea
-damage to chest wall
-rib contusion
-paralysis of respiratory muscles
hyperventialtion - ANS--increased air entering alveoli
-decreased PaCO2 < 35 mm Hg (hypocapnia) due to increase respirations
cause of hyperventilation - ANS--pain
-fever
-anxiety
-obstructive and restrictive lung disease
-sepsis
-brain stem injury
Hypoxemia - ANS-deficient levels of blood O2
Hypoxia - ANS-decreased in tissue oxygen
High V/Q imbalance - ANS-ventilation with no perfusion
, -physiologic dead space
Low V/Q mismatch - ANS--Lower PaO2
-airways obstructed
-hypoxemia results
shunt effect - ANS--results from blood flowing from the right side to the left side of heart
without passing through ventilated areas of the lung (localized pneumonia- alveoli are
perfused but not ventilated)
Diffusion - ANS-passive movement of gas between air spaces in lungs and bloodstream
(high concentration to low concentration area)
ex: change in diffusion = pulmonary edema, HF
What is the pathophysiology of pulmonary hypertension? - ANS--walls of pulmonary
vessels thicken from an increase in the muscle
-becomes fibrotic
-sustained pulmonary HTN results in formation of a network of blood vessels (plexiform)
that impede blood flow
Treatment for pulmonary HTN - ANS--supplemental O2
-vasodilators
-diuretics
-heart/lung transplant
-surgery if left to right shunt causing increased work for R ventricle
How doe HTN progress to Cor Pulmonale? - ANS--Consequence of HF but more so
from pulmonary HTN
-*Eventually Cor Pulmonale and right ventricular failure will develop if severe pulmonary
HTN continues b/c of persistent back pressure to the right sided HF*
What causes pulmonary vasoconstriction? - ANS-hypercapnia, hypoxia, acidemia,
increased H+ concentration
-not enough O2 getting into lungs so heart work load increases
-vasoconstriction causes increase in resistance/afterload which causes Cor Pulmonale
(right sided HF)
What is Cor Pulmonale aka right sided HF? - ANS-an enlargement of the right ventricle
due to high blood pressure in the lungs caused by chronic lung disease
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