quotes from rosens notes.... lecture 7 Flashcards
which divisions of the lung conduct zone
bronchi
bronchioles
terminal bronchioles
what is the conduction zone for?
BULK movement of air
no respiratory function
helps defend the lungs
which divisions of the lung are respiratory (aka transitional)
respiratory bronchioles
alveolar ducts
alveolar sacs
what is the respiratory zone for?
gas exchange via the acinus
how does branching of bronchioles affect surface area?
it durastically increases surface area and thus, the air VELOCITY SLOWS down
what provides circulation in the alveolus
pulmonary artery, capillary bed and pulmonary vein
distance between blood and air in an alveolus
<0.5 microns. tiiiiny
what are some lung/respiratory system functions
humidification
warming
filtration
if your lung dries out, what happens
“dessication of respiratory surface … could lead to infection”
the URT filters air. what are the four sizes of particles?
where are those particles trapped?
larger than 10 microns ==> hairy nose
5-10 microns ==> sinuses, pharynx
2-5 microns ==> bronchioles
alveoli (this is where smoke goes)
where is mucous not present
mucous only goes as far as terminal bronchioles. this makes suspension of very fine particles in the acini very troublesome
how do you get rid of particulates
cilia ==> they beat and propel the mucous suspension toward pharynx
alveolar macrophages ==> phagocytic destruction of debris, microbes
sneezing and coughing
sneezing and coughing is effective for?
the first 12 ish branch points of the R. system
what space allows for lung mvmt
the intrapleural space couples the lung surface to the chest wall and diaphragm
what does the lung natrually wants to __ but we prevent it by __
collapse; the recoil force of the chest wall and diaphragm give it a slightly negative INTRAPLEURAL pressure, and zero INTRAPULMONARY pressure
how does a lung collapse
by exposing the chest cavity to atmospheric pressure
or
introducing air into the intrapleural space (pneumothorax)
majority of inspiration is due to? the rest is?
diaphragm (75%)
the rest is external intercostals, scalene, sternomastoid…. (thats not a muscle?)
why can you breathe without much resistance
there is a large cross sectional area of the LRT, (therefore, low TOTAL resistance to flow).
this set-up allows you to move large amounts of air with very small pressure differences
expiration at rest
due solely to recoil of elastic elements in lungs
they recoil until their force equals the force of the chest wall
inadequate expiration results in
limited USEFUL lung capacity
airway resistance =
how easily does air go throuigh the tracheo-bronchial tree?
> asthma
> CF
thoracic resistance examples
fractured rib
obesity
surface tension tries to minimize?
surface area of the lyng
compliance =
change in volume / change in pressure
in alveoli what does DECREASED compliance try to do to your lungs? Compliance is inversely proportional to?
it tries to keep them closed (tries to collapse them). Compliance inversely related to surface tension. (increased tension= decreased compliance)
what does surfactant do to the lung?
induces an AREA DEPENDANT effect on tension, which changes how water molecules interact
as a chemist, my (more accurate) definition is… “it helps water attract to other surfaces, thereby reducing waters attraction to itself… lowering tension”
relationship between radius and pressure
a small R needs more pressure to blow up an alveolus
what does surfactant do to:
work, compliance, tension
reduces work increases compliance (aka decreases resistance) decreases tension (compensates for small radius of alveoli)
how do you get preemies to breathe
positive pressure vent.
> surfactant production begins @ 32 wks
tidal volume=
NORMAL breath volume
aka TV
expiratory reserve volume=
ERV; maximum volume of forced exhale AFTER NORMAL breathing
inspiratory reserve volume =
IRV; maximum volume of forced inspiration AFTER NORMAL breathing
vital capacity=
MAX volume you can INHALE and EXHALE
VC = TV + IRV + ERV
residual volume =
RV; volume of air left in lungs AFTER MAXIMUM EXHALE
functional residual capacity=
- volume of air in lungs AFTER NORMAL EXHALE
- describes the balance of force between lung collapse and chest wall recoil
downfall of vital capacity measurements
they are only static numbers, they don’t tell you anything about the flow of air in a lung
how do you measure dynamic properties of a lyng? whats normal
- forced expiratory volume (over 1 sec) and forced vital capacity; ** we did this in lab.
- FEV / FVC should be about 0.8
- useful for COPD and asthma
what causes airway resistance
- due to frictional loss of energy from walls of airways
obstructive diseases
increased airway resistance and CO2 retention
Asthma is an example of
bronchospastic or reversible obstructive condition because the increase in resistance is due to bronchocontriction
exercise induced asthma
- cough, wheezing, chest tightness
- may be due to heat and water loss during rapid respiration
- (or maybe just that it doesn’t bother you until you try do exercise)
emphysema is an example of
- irriverible obstructive condition
- forced residual capacity increases and elastic work decreases
- airway ressitance increases
- tendency to retain co2
what happens to FEV/FVC in obstructed airway
- decreased ratio
- result of increased airway resistance
- in some cases you also have a loss of lung elasticity/recoil
examples of restrictive diseases
- atelectisis
- consolidation
- pleural effusion
- respiratory distress syndrome
- pneumothorax
- ** i would add scoliosis and broken rib
atelectesis =
collapse of part or entire lung
cnosolidation =
filling of alvolar spaces with inflammatory exudates
pleural effusion=
- heart failure,
- hypoproteinemia
- infection
- neoplasm
- thoracocentesis
respiratory distress syndrome
most common example of restrictive disease usually in premature babies, but also in :
- near drowning
- acid aspiration
restrictive disease=
- reduction of total lung capacity
- although FEV/FVC increases, the absolute movement of be air decreases because the functional residual capacity decreases
dead space =
volume of air in first 16 segments that does nothing for oxygen absorbtion…. only for air condutiobn
to live, __ must be greater than ___
TV must be larger than dead space
compare rapid shallow breaths to deep slow ones
volume wise, the two may move the same amount of air.
rapid breathing does not overcome the DEAD SPACE, so alveoli don’t oxygnate as well
good analogy for dead space?
think about snorkeling with suuper long tube…. it wouldn’t work. you’d keep breathing the same air
