Respiratory Physio Flashcards
main muscle of inspiration
diaphragm
muscles of inspiration
diaphragm
ext intercostal
accessory muscles of inspiration
serratus anterior
scalene
scm
accessory muscles of expiration
rectus abdominis
internal intercostal
abdomen is sucked in while accessory muscles of inspiration are contracting
paradoxical breathing
indicator of impending respiratory failure
paradoxical breathing
difference in alveolar and pleural pressure
transpulmonary pressure
pressure of fluid in the space between parietal and visceral pleura
pleural pressure
pressure inside alveoli
alveolar pressure
negative intrapleural pressure
created by movement of diaphragm downward and chest wall outward. the driving force of inspiration
driving force of expiration
increase in intrapleural pressure, by movement of diaphragm upward and chest wall inward
normal compliance
200ml/cm H20
measure of lung distensibility/how lung accommodate air
compliance
defined as the change in volume required for a fractional change of pulmonary pressure
compliance
property of lung that makes it resistant to deformation
elastance
defined as the pressure required for a fractional change im lung volume
pulmonary elastance
increased compliance
reduced elastance
obstructive lung disease
increased elastance
decreased compliance
restrictive LD
created by the attractive forces between water molecules
surface tension
complex phospholipid secreted by type 2 pneumocytes
minimizes the interaction between alveolar fluid and alveolar air
surfactant
reduces the compliance resistance work of the lung
surfactant
characterized by small alveoli+ increased surface tension+ elevates collapsing pressure on baby born <34 wks
neonatal respiratory distress syndrome
work of breathing required to overcome resistance in airway
airway resistance 25%
work of breathing required to expand lung against chest recoil forces
compliance/resistance 75%
work of breathing required to overcome viscosity of lung and chest wall structure
tissue resistance
states that the longer the airway, the higher the resistance
poiseuille’s law
area of highest airway resistance
medium sized bronchi
airway resistance in large airways
large airways are arranged in SERIES= resistance is additive
airway resistance in small airways
small airways are arranged in PARALLEL= decreased resistance
volume of air inspired with EACH normal breath
tidal volume
normal tidal volume
500ml
volume inspired over and above the tidal volume
the maximum volume that can be inspired beyond a normal TV
inspiratory reserve volume
normal IRV
3000 ml
the volume that can be EXPIRED after EXPIRATION of TV
the maximum volume that can be expired after a normal tidal expiration
Expiratory reserve volume
normal ERV
1,100ml
volume remaining in lungs after maximal expiration
residual volume
normal RV
1,200
TV + IRV
inspiratory capacity
normal IRV
3500
ERV + RV
functional residual capacity
normal ERV
2300 ml
maximum volume of air expired after maximal inspiration
vital capacity
tv+ IRV + erv
vital capacity
normal vc
4,600
maximum volume of air in lungs after maximal inspiration
total lung capacity
TV+irv+ erv+ rv
total lung capacity
maximum amount of air that can be exhaled in 1 second after a maximal inspiration
fev1
normal fev1/fvr ratio
80%
meaning: able to exhale 80% of what was inhaled on the 1st second of exhalation
fev1/fvc ratio in copd
decreased
fev1/fvc ratio in restrictive LD
increased
blood supply to lungs
bronchial artery
pulmonary artery
branch of thoracic aorta
high pressure,low flow
supply the conducting zone
bronchial arteries
low pressure,high flow
receive 100% of cardiac output
pulmonary artery
portion of lungs that are ventilated but no gas exchange
pulmonary dead space
3 types of pulmonary dead space
anatomic
alveolar
physiologic
volume of air in conducting airways not involved in gas exchange
anatomic dead space
150 ml
nose to terminal bronchiole
ventilated alveoli but not perfused
alveolar dead space
sum of anatomic and alveolar dead space
physiologic dead space
anatomic dead space is INCREASED during?
mechanical ventilation
ET will shorten the dead space but the tubings in MV will increase dead space
zone of lung that has no blood flow during cardiac cycle
zone 1
lung apices
seen in pathologic conditions only
zone with intermittent blood flow during cardiac cycle, no blood flow during diastole
zone 2
in upper 2/3 of lungs
zone with continuous blood flow
zone 3
formula of minute ventilation
rr x tv
normal: 6L/min
amount of air that moves into respiratory passages per minute
minute ventilation
rate at which new air must reach the gas exchange area
alveolar ventilation
DLCO
uses carbon monoxide
V/Q at rest
0.8
v/q of lung apex
3.3
lung apex is underperfused and overventilated
v/q of lung base
0.6
overperfused but underventilated
controls basic rhythm of respiration/ inspiration
dorsal respiratory group
stimulates expiratory muscles as in forced expiration
ventral RG
inhibits inspiration
pneumotaxic center
increase duration of inspiration
apneustic center
group of nerve terminals sensitive to changes in ph, paO2, paCO2
chemoreceptors
stimulate hyperventilation in response to increased paCO2 amd decreased ph
central chemoreceptor
responds to ph, paco2, paO2
peripheral chemoreceptors in carotid and aortic bodies
airway distention– further inhibit inspiration
hering breuer reflex
