Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

69 Cards in this Set

  • Front
  • Back
Conducting zone
-Larger airway
-Does NOT participate in gas exchange
-Warms and humidifies air
-Evenly distributes air in deeper sections of lung
-Trap toxins, dust, bacteria
Respiratory zone
Alveoli - gas exchange
Describe alveoli
Thin walls and large surface area - air-blood barrier
Sequence of events in inspiration
Inspiratory muscles contract (diaphragm drops, rib cage rises) --> thoracic volume increases --> lungs stretched --> intrapulmonary pressure drops to negative --> air rushes into lungs down pressure gradient until pressure is 0 again
Sequence of events in expiration
Inspiratory muscles relax (diaphragm rises, rib cage descends due to gravity) --> thoracic volume decreases --> elastic lungs recoil passively --> intrapulmonary pressure rises to positive --> air rushes out until pressure is 0 again
Pleural pressure
-pressure in the pleural space
-negative at rest due to opposing forces of chest wall and lung - chest wall wants to go out, lungs want to come in (collapse), this negative pressure keeps lungs from collapsing
Alveolar pressure
Pressure inside alveoli
Transmural pressure
2 parts:
-Transpulmonary - difference between alveolar and pleural pressures, lungs will not collapse as long as this pressure is positive
-Transairway- difference between airway and pleural pressures, keeps airways open during forced expiration
Describe pressures at rest
At rest alveolar pressure = barometric pressure = 0
Pleural pressure is NEGATIVE, transpulmonary pressure is POSITIVE
Pleural and transpulmonary pressures exert equal and opposite forces, chest wall has potential to recoil outward and lungs have potential to recoil inward
Describe pressures during inspiration
Alveolar pressure is less then barometric pressure
Pleural pressure becomes more negative and transpulmonary pressure becomes more positive
As thoracic volume increases, alveolar pressure becomes negative, creating a pressure gradient. Pleural pressure becomes more negative as a result of increase in thoracic volume and force of elastic lung recoil
Describe pressures during expiration
Alveolar pressure is greater then barometric pressure
Alveolar pressure becomes positive because forces pushing for lung recoil compress air in alveoli.When alveolar pressure becomes greater then barometric, pressure gradient is created and air rushes out of the lung. As thoracic volume decreases, pleural pressure becomes less negative and transpulmonary pressure becomes more positive
Describe pressures during forced expiration
Alveolar pressure is twice as much as barometric. Both pleural and transpulmonary pressures become positive due to contraction of expiration muscles. Greater pressure in alveoli compared to barometric creates a large pressure gradient resulting in rapid and forceful expiration
What happens in pneumothorax
Puncture wound lets air in the pleural space and pleural and transpulmonary pressures become 0. Without these pressures lungs collapse and chest goes outward.
Tidal volume
Normal breathing
Inspiratory reserve volume
Max amount of air that can be inhaled after normal inspiration
Expiratory reserve volume
Max amount of air that can be exhaled at the end of tidal volume
Residual volume
Volume of air remaining in lungs after maximum expiration - CAN NOT BE MEASURED WITH SPIROMETRY
Inspiratory capacity
Max amount of air inhaled following normal expiration - from lower end of tidal volume and up
Functional residual capacity
-amount of air remaining in lungs at the end of tidal volume
Vital capacity
Everything except residual volume - max amount of air that can be exhaled
Total lung capacity
amount of air in lungs following max inspiration
Vital capacity is sum of _
Tidal volume + expiratory reserve volume + inspiratory reserve volume
Inspiratory capacity is sum of _
Tidal volume and inspiratory reserve volume
Functional residual capacity is sum of _
Expiratory reserve volume and residual volume
Total lung capacity is the sum of _
4 volumes - tidal volume + inspiratory reserve volume + expiratory reserve volume + residual volume
Forced expiratory volume
amount of air that can be forcibly expired per unit time ( 1-3 sec)
Forced vital capacity
Amount of air that can be forcibly expired following maximum inspiration
What ratio is used to differentiate lung diseases
Obstructive lung disorders
Obstruction of small airways
Restrictive lung disorders
Reduced compliance of lung or chest wall or weakening of inspiratory muscles
Normal vs patient with obstructive disorder
Obstructive disorders include asthma and emphysema and are characterized by slow air movement during forced expiration.
FEV1 will be greatly reduced
FVC will be also reduced
Residual volume will be increased since a lot of air is left and cannot get out.
FEV1/FVC ration would be decresed drastically
Normal vs patient with restrictive disorder
Restrictive disorders are disorders like lung fibrosis that reduce lung compliance.
Maximum inspiratory volume and vital capacity will be reduced. Amount of air exhaled will be reduced since air inhaled is also reduced
FEV1/FVC ratio will be slightly increased compared to normal patient
Define anatomical dead space
Part of airway where air fills lungs but doesnt contribute to gas exchange
Define alveolar dead space
Normally not present but if alveoli stop participating in gas exchange due to collapse, blockage or reduced blood flow, you get alveolar dead space
Define physiological dead space
Physiological dead space = anatomical dead space + alveolar dead space
Alveolar ventilation rate
Va = breaths per min (f) * (tidal volume - dead space)
Dead space = anatomical dead space + alveolar dead space
In normal lungs, dead space = anatomical dead space
Minute ventilation
Breaths per min (f) * tidal volume - total amount of air inspired per min
What happens to alveolar ventilation rate when patient is hyperventilating
Becomes 0
What happens to alveolar ventilation rate when patient is hypoventilating
Define distensibility of lung
Ease lung is stretched/inflated
Increasing distensibility decreases _
Elastic recoil of the lung
_ is measure of distensibility
Conditions with increased lung compliance
Infection, COPD, environmental toxins
Conditions with decreased lung compliance
Restrictive - fibrosis
About 2/3 of work required to inflate lung is due to _
Surface tension
Surface tension decreases _
Alveoli diameter and surface area - producing inward force and collapsing pressure
Collapsing pressure is directly proportional to _ and inversely proportional to _
Directly proportional to surface tension and inversely proportional to radius
-Allows alveoli of different sizes to coexist and be stable at lower lungs volumes
-Also increases lung compliance so decreases work needed for inflation of the lungs
-Lower surface tension
Main cause of neonatal respiratory distress
Lack of surfactant
Airflow equals to
Pressure /Resistance
Major site of resistance in lungs
Medium bronchi
Factor affecting airway resistance
- Lung volume - decrease volume - increase resistance
-Smooth muscle tone - sympathetic - bronchial dilation, parasympathetic - bronchial constriction
-Gas density - deep sea diving
Difference between partial pressure of O2 in lungs and atmospheric air
When you figuring out partial pressure in lung need to subtract partial pressure of water vapor
Px = (Pb- Ph2o) * F
Driving force for diffusion in lungs
Difference in partial pressures across membrane
Decrease functioning alveoli, decreases surface area
Increases membrane thickness
Increases capillary perfusion so increases surface area
3 forms of gases in solution
1) Dissolved
2)Bound - O2, CO2, CO bound to hemoglobin
3)Chemically modified - CO2 travels as bicarbonate
Which gases contribute to partial pressures
Alveolar perfusion and ventilation are highest at _ , lowest at _
Highest at base, lowest at apex
V/Q (ventillation/perfusion) ration is higher at _ , lower at _
Higher at apex, lower at base
You get overventilation at _
and overperfusion at _
Overventilation - apex
Overperfusion - base
Venous admixture
2 causes
Mixture of oxygenated and deoxygenated blood
1) physiological shunt - small amount of blood that doesnt participate in gas exchange and leaves pulmonary capillaries unoxygenated - 1 % of CO
2)low V/Q ratio - insufficient alveolar ventilation
If partial pressure limits exchange it _ , if blood flow its _
Diffusion limited - CO
Perfusion limited - N2O
2 types of O2 transport
1) Dissolved
2) Bound to Hb - 98%
Shift to left in Hb curve means _ , right _
Left - increased affinity - makes unloading at tissues more difficult
Right - decreased affinity - unloading of O2 at tissues
Factors that can cause right shift in Hb curve
1) acidosis - Bohr effect
2)increase temp
3) increase 2,3 - BPG
Factors that cause left shift in Hb curve
1) alkalosis
2)decrease temp
3) decrease 2,3 BPG
3 transport mechanisms of CO2
1) dissolved
2)bound to hemoglobin
3) as bicarbonate