Respiratory System Flashcards
upper airway muscles (33)
active during inspiration, keep airway open
nasal and oral cavities, pharynx, larynx (vocal cords)
Trachea
Lungs
- bronchi –> bronchioles –> alveoli
smooth muscle and connective tissue
pulmonary circulation
Sleep apnea
reduction in upper airway path during sleep. Airflow is blocked.
caused by loss of muscle tone, anatomical defects
Risk factors of sleep apnea
Lack of excitatory drive - reduction in muscle tone
Filtering Action regions
conducting zone - mucus-producing (goblet) cells and ciliated cells
trap and remove inhaled particles
muco-cilliary escalator
Role of goblet cells and ciliated cells
Trap inhaled particles and remove them. Prevent it from reaching respiratory zone
SOL layer
low density. Free cilia movement
CILIATED cells that have free movement
GEL layer
Goblet cels (mucous)
high viscosity and elastic properties
traps inhaled particles
Removal of mucous
cilia movements
downward (nasopharynx)
upward (trachea)
eliminated through esophagus
Smoking affect on cilia and goblet cells
chemicals/tar effect cilia movement, preventing the removal of particles
Where are macrophages located
Alveoli
Last defence to inhaled particles
Pulmonary fibrosis
silica duct and abestos
lungs cannot expand due to collagen buildup over time
Spirometry
Pulmonary function test
rate of insp and exp air
measure volume of air inspired and expired by the lungs
AMOUNT AND RATE OF AIR BREATHED IN AND OUT OVER TIME
Atelectasis
complete or partial collapse of lung (or lobe of lung)
Occurs when alveoli become delated/flat
Can you measure residual lung volume?
NO it cannot be measured via spirometry
Tidal volume
volume of air moved IN or OUT of respiratory tract during each ventilation cycle
inspiratory reserve volume
additional volume of air that can be forcibly inhaled following NORMAL RESP
simply inspire maximally, MAXIMAL POSSIBLE INSPIRATION
expiratory reserve volume
additional volume of air that can be forcibly exhaled following normal expiration
simply expire maximally MAXIMUM VOLUNTARY EXPIRATION
residual volume RV = FRC - ERV
the volume of air remaining in the lungs after a MAXIMAL EXPIRATION. cannot be expired at all (no matter what)
RV = FRC - ERV
Capacities
SUM of two or more lung volumes
VC = TV + IRV + ERV
VITAL CAPACITY - maximal amount of air that can be forcibly exhaled after maximal inspiration
IC = TV + IRV
INSPIRATORY CAPACITY - maximal volume of air that can be forcibly exhaled
FRC = RV* + ERV
FUNCTIONAL RESIDUAL CAPACITY - volume of air remaining in the lungs at the end of a normal expiration
cannot be measured by spirometry
TLC = FRC + TV + IRV = VC + RV*
TOTAL LUNG CAPACITY - the volume of air in the lungs at the end of a maximal inspiration
cannot be measured by spirometry
Lung volume
Tidal volume - 0.5 L
Flow (calculation)
Total/minute ventilation
total amount of air moved into the respiratory system per minute
Total/minute ventilation = TV x resp frequency = 0.5L x 15bpm = 7.5L/min
Alveolar ventilation (Va)
amount of air moved into alveoli per minute
depends on the anatomical dead space - constant, not available for gas exchange
AV = (0.5 - 0.15) L x 15/min = 5.25 L/min
Which sis more effective - DEEP breathing or INCREASED RATE (shallow)?
Deep breathing - higher alveolar ventilation
FEV1
FORCED EXPIRATORY VOLUME in 1 sec
health person can empty most air out of their lungs in one second
FVC
FORCED VITAL CAPACITY
amount of air that is blown out in one breath after max inspiration as fast as possible
Spirometry Test Patterns (3)
- normal (age, gender, weight, height)
- obstructive (difficulty exhaling - asthma)
shortness of breath, air comes out slowly - restrictive (difficulty fully expanding - fibrosis, ALS, MS)
stiffness in lungs
Helium dilution technique
helium is insoluble in blood, EQb after a few breaths, Measure the concentration at the end of expiratory effort
measures communicating gas or ventilated lung volume
Mechanics of Ventilation
Static properties of lung (mechanics of ventilation)
NO AIR IS FLOWING maintains chest wall volume Intrapleural ressuer (Pip), transpulmonary pressure (Ptp)
Dynamic properties of lung (mechanics of ventilation)
LUNGS ARE CHANGING VOLUME
air flows in and out
permits airflow
Alveolar pressure (Palv)
Boyle’s Law
for a fixed amount of an ideal gas; fixed temperature
Pressure and volume are INVERSELY proportional
P1V1 = P2V2 (contant T)
gas molecules are in constant motion, creating pressure:
EXPIRATION: decrease volume, increased pressure (alv)
INSPIRATION: increased volume, decreased pressure (alv)
Ventilation
exchange of air between the atmosphere and alveoli
Bulk flow: gas moves from HIGH pressure to LOW pressure
F = deltaP / R
deltaP —> (Palv-Patm)
What creates pressure
movement of gas molecules in a container
How ia airflow created
change in volume and pressure produces airflow
pressure difference is generated, air moves via bulk flow HIGH to LOW pressure
F = deltaP / R
Elastic recoil
interaction between lung and thoracic caste determines lung volume
Lungs tend to collapse due to elastic recoil
chest wall - pulls thoracic cage outward due to elastic recoil
EQb –> inward recoil balanced with outward recoil
Intrapleural Pressure (Pip)
Intrapleural fluid - reduces friction of lung against thoracic wall during breathing
PRESSURE IN THE PLEURAL CAVITY
always subatmospheric
if Pip = Palv —> lungs would collapse
Transpulmonary pressure
FORCE RESPONSIBLE FOR KEEPING ALVEOLI OPEN
grater than 0 to keep lungs expanded
determines lung volume (static) not airflow
airway resistance
- Inertia of respiratory system (negligible)
- Friction
- lung tissue with itself
- lung and chest wall tissue
- resistance of air flow
Laminar flow
relatively little energy in airflow RESISTANCE, small airway are distal to terminal bronchioles
Transitional flow
extra energy needed to produce vortices, resistance increases
airflow is transitional throughout bronchial tree
Turbulent flow
effective resistance to airflow is highest
LARGE AIRWAYS (trachea, larynx, pharynx)
radius is large and linear air velocities may be extremely high
Poiseuille’s law
laminar flow
R = 8nl / pi r^4
airway resistance is proportional to the viscosity of the gas and the length of the tube, but inversely proportional to fourth power of the radius
R to airflow is highly sensitive to the airway radius
Disease conditions of Airway resistance
typically impacted by small airways more than large ones
- smooth muscle wall contraction
- edema occurring on the walls of alveoli and bronchioles
- mucus collection in lumens of bronchioles
Lung compliance
Dynamic vs static
measure of elasticity of lungs, lung expansion
CHANGE IN LUNG VOLUME produced by change in TRANSPULMONARY PRESSURE
static - measured during no gas flow
dynamic - measured during gas flow
Static compliance
no air flow through
Dynamic compliance
measured during air flow
reflection of lung stiffness and airway resistance
Emphysema - high compliance
loss of alveolar tissue (less gas exchange)
floppy lungs, less elastic recoil
Hysteresis
defines the difference between inflation and deflation compliance paths
Grater pressure difference is required to open a previously closed (narrowed) pathway than to keep an open airway from closing
Elastic components of lungs
elastin - weak spring, LOW tensile strength, extensible
collagen - strong twine, HIGH tensile strength, inextensible
What determines Lung Compliance
Elastic components - elastin, collagen
Surface Tension - air/-water interface within the alveoli
alveolar surface tension
water molecules at the surface of a gas-liquid interface are attracted strongly to the water molecules within the liquid mass
surface tension measures the attractive forces acting to pull a liquid’s surface molecules together
Factors that affect pressure-volume relation
air inflation
liquid inflation
Laplace’s equation
describes EQb:
P=2T/r
the smaller the bubbles radius is, the grater pressure needed to stay inflated
Alveolar surfactant
Produced by Type II alveolar cells
Lowers surface tension ( level of alveoli)
Stable against collapse
Surfactant and surface tension
Phospholipids mixture
Dipalmitol-phosphatidylcholine
breaks the strong attractive forces at the surface of water