Test 2 - Study Guide Flashcards
Define the terms static and dynamic?
-Static: at rest
-Dynamic: with movement
What is compliance and what is elastance?
-Compliance: how easy or difficult it is to distend the lungs when force is applied
-Elastance: the lungs attempt to return to original size and shape when force is not being applied
What is normal lung compliance and how do the numbers change when it improves/ worsens?
Normal Cstat= 100 ml/cmH2O
Lower# -> worse compliance
higher#-> better compliance
Are large alveoli more or less likely to collapse when compared to a small one?
Less likely
What saves the small alveoli from collapse?
Surfactant
What type of cell creates surfactant and what does surfactant do for the lung?
Type II granular pneumocytes. Surfactant decreases surface tension (enhances alveolar integrity)
Does length or radius have more effect on Raw?
Radius (when the radius is cut in half, it becomes 16x more pressure to maintain the same flow)
What is Raw and what is the normal range?
Airway resistance. Normal Raw = 0.5-2.5 cmH2O/L/S
A time constant is
The time necessary to inflate an alveolus to 60% of its potential filling capacity
Know the normal Vt, F, and I:E ratio
Vt= 7-9ml/kg of IBW f=12-20 I:E= 1:2 (need to know how to calculate IBW and Vt range)
What is minute ventilation and what is the calculation for it?
Minute ventilation is the volume of air that moves into or out the lung in one minute. MV=Vt x f
How does ventilation differ from respiration?
Ventilation is the moving of air into and out of the lungs. Respiration is the diffusion of gasses across a membrane. We can replace ventilation, but not respiration.
What causes air to flow into and out of the lungs (very basic)?
Diaphragm contracts->pressure in the lungs is less that the pressure in the atmosphere->air goes in until alveolar pressure is equal to barometric pressure->diaphragm relaxes->pressure in the lungs is greater than the pressure in the atmosphere->air goes out until alveolar pressure is equal to barometric pressure
How does the equation for alveolar ventilation differ from the equation for minute ventilation and what is the definition of alveolar ventilation?
Alveolar ventilation is the volume of gas that reaches the alveoli and takes part in gas exchange. This equation differs from minute ventilation because we must account for deadspace.
VA =(Vt–VD) X f
What is the definition of Deadspace and what are the three types of deadspace?
Deadspace is the volume of gas that doesn’t take place in gas exchange.
-Anatomic – Upper airways (i.e. conducting airways)
-Alveolar – Non-perfused alveoli (i.e. pulmonary embolus)
-Physiologic – Sum of the two (aka total)
Normal (anatomic) deadspace is
1 ml/lb. of IBW.
In the upright lung, where does more perfusion take place? Ventilation?
More ventilation takes place in the apices. More perfusion takes place in the bases.
What are the seven different ventilatory patterns that were reviewed and what are the definitions of each?
Eupnea – Normal breathing
Apnea – Not breathing
Hyperpnea – Breathing volume is increases ( with or without increased f)
Hyperventilation – Breathing off more CO2
Hypoventilation – Not breathing off enough CO2
Tachypnea – Increased f
Dyspnea – Difficulty breathing (Subjective)
