pulmonary ventilation

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What 2 things does Respiration refer to?: 1. Gas exchange
2. Cellular respiration
what gas exchange occurs in respiration?: O2 for CO2
What are the 2 zones within the airway?: 1. Conducting zone
2. Respiratory zone
What 3 resp structures compose the conducting zone?: -Bronchi
-Bronchioles
-Terminal bronchioles.
What 3 resp structures compose the respiratory zone?: -Respiratory bronchioles
-alveolar duct
-alveolar sacs
Which zone has gas exchange?: the respiratory zone.
What's the conducting zone also called? Why? -What takes place there?: Dead zone - no gas exchange.
DOES: Warm air, humidify it, remove junk from it.
What 2 properties const. dead space?: -Cartilage to prevent collapse
-Smooth muscle to regulate airflow.
What characteristic enhances gas exchange in the resp zone?: Alveoli, providing large surface area.
how many alveoli/lung?: approx 500 million.
What pressures affect breathing?: -Atmospheric
-Pleural fluid
-Alveolar
what is outside pressure?: Atmospheric = Barometric = 760 mm Hg, but we say 0 cm of H2O.
What is F = to?: F = (Patm - Palv)/Resist.
When is there no airflow in or out of lungs?: when Patm = Palv
What direction does air flow when Palv is -Positive? -Negative?: Positive, flow out

Negative, flow in.
When is pleural pressure negative?: Always.
What makes neg. Pleural press?: Stretch reflexes of
-Lungs, want to collapse.
-Thoracic wall, want to expand.
Together they increase Pleural space volume thus decr. press.
What's the significance of having a negative Ppl all the time?: keeps the lungs expanded.
What controls the volume of the chest cavity?: Volume of pleural space, controlled by the DIAPHRAGM contracting.
What is a hole in the chest wall called? What's its affect?: Pneumothorax - makes Pleural pressure equal Barometric, lungs deflate and collapse.
What needs to happen for normal inspiration?: Increase chest cavity volume to decrease alveolar pressure.
-DIAPHRAGM CONTRACTION.
What allows increased inspiration?: Recruitment of other muscles.
-External intercostals
-Neck accessory muscles.
What occurs in normal expiration?: PASSIVE relaxation of the diaphragm.
What allows increased expiration?: Contraction of INTERNAL intercostals and abdominal muscles.
what measures resp volumes and capacities?: a spirometer
What is tidal volume?: the volume moved merely by breathing - the air going in and out of your airways.
what is IRV?: inspiratory reserve volume - the additional space for forced inspiration beyond normal amt.
what is ERV?: expiratory reserve volume - the amt of space you can breathe out hard
what is RV? whats the typical value?: residual volume - the air you can never breathe out.
Typically 1 L
What is Vital capacity? What is it equiv to? What is the typical value?: Total amt of air you can move - total lung capacacity
VC= Tidal vol + IRV + ERV
Typical value: 5 L
what is the typical tidal volume?: .5 L (500 mL)
what is "forced vital capacity"?: the rate of your vital capacity breathed out as fast as possible in one second. basically just breathing out hard and fast.
what is the problem in an "Obstructive Disorder"?: Patient can't breathe out enough
-Forced vital capacity decreasd, -Makes Residual vol increased.
In obstructive disorders, what are the values of: Forced Vital Capacity? Residual volume? Total lung capacity?: 3 L - FVC is decreased from 5 L
3 L - RV increased from only 1 L
6 L - TLC is normal.
What is the cause of emphysema?: -Loss of alveoli/elastic recoil.
-Result: lungs dont want to deflate as much so passive exhalation is impaired.
What's a "Restrictive Disorder?" What are two categories of it?: Problem in air inhalation
-Acute: edema/fluid in lungs.
-Chronic: fibrous growth in lungs.
In restrictive disorders, what are the values of: FVC RV TLC: FVC: 3L (decreased)
RV: 1L (Normal)
TLC: 4L (decreased)
Is Asthma a restrictive or obstructive disorder? What causes it?: Obstructive disorder.
Cause: allergy/stress constricts airways; increased chest compression collapses lungs, traps air inside lungs and can't push it out.
What is dead space? What are 2 types? Which is normal/abnormal?: Space in lungs not involved in gas exchange.
-Anatomic - normal
-Alveolar - abnormal, diseased.
What is Anatomic dead space?: Air in the conducting zones.
Typically about 150 ml
What is Alveolar dead space?: Alveolar air that no blood is flowing past; no gas exch. here.
What is Total ventilation? Does it adequetely represent breathing?: the amnt of air moved / min.
Typ: 500ml/bth x 12b/m = 6000
No - it's not necessarily the amount of air in gas exchange.
What is a better representation of gas exchange?: Alveolar ventilation -
Av = (Tidal vol - Anatomic dead space)x Breathing frequency.
(500 - 150)x 12 = 4200 ml/min
Better to breathe deep/slow or Shallow/fast?: Deep/slow - if you breathe shallow you only fill up your dead space.
What do snorkelers have to do? Why?: Breathe more deeply because anatomic dead space is increased.
What is Airway resistance proportional to?: 1/airway radius to 4th power.

Incr airway radius decrs resistance, vice versa.
In airways: Where is greatest resistance? Where is most important R?: Bronchi are most resistant b/c there are so FEW of them.
Most important R in bronchioles b/c have smooth muscle and there are many of them.
What 3 things control airway resistance?: 1. Sympathetic nervous sys.
2. Parasymp nervous sys.
3. CO2 in the tissues.
How does the SNS control airway resistance?: By releasing Norepi and Epi to act on Beta2 receptors and cause DILATION so you can run.
How does the PNS control airway resistance?: By releasing AcH to muscarinic receptors to cause CONSTRICTION so you don't waste air while sleeping.
What's a common Asthma treatment?: Beta2 receptor agonist - acts like EPI so you can breathe better.
How does CO2 control airway resistance?: Normally it's in high levels in the capillaries to bronchioles.
When Blood flow blocked, CO2 is low, so bronchioles constrict.
What should I remember to predict how the bronchioles will act in response to blood flow?: Decrease BF, Decrease Bronch'ol.

BLOOD FLOW MATCHES AIR FLOW!!!!
What is "COMPLIANCE"?: the measure of how distensible the lungs are - how easily they inflate.
What does Compliance = ?: chng in Vol
Compliance = ------------------
chng in Pressure.
When is Compliance increased? What is the Press/vol relation in this case?: Emphysema - Inflating easier b/c elastic recoil is decreased.

Changes in pressure cause bigger volume changes - Barrel chested.
When is compliance decreased? What is the P/V relnshp?: In Restrictive disorders (i.e., edema; lungs harder to inflate.
Pressure changes result in unremarkable volume changes.
What is the purpose of SURFACTANT?: It decreases surface tension in the alveoli by disrupting hydrogen bonds in the water coating, thus preventing collapse of the alveoli.
What secretes surfactant?: Type 2 alveolar cells
What is surfactant made of?: Lipoprotein - fat dirsupts hydrogen bonds and decreases water surf tension in alveoli.
Where is surfactant more important, in small or large alveoli?: Small - if wasn't there, they would collapse.
When in development is surfactant made?: Late in fetal dvelopment; therefore preemies lack it, and their alveoli collapse.
what does lack of surfactant do to compliance and work in breathing?: Decreases compliance.
Increases work you have to do to breathe.

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