Exam 2 Flashcards
What does P IP & P PL stand for?
Pleural Pressure
- What does P A stand for?
Alveolar pressure
- What does P EL & P ER stand for?
Elastic recoil pressure
- What does P TP stand for?
Transpulmonary pressure
- What is the normal pleural pressure & when is it measured?
-5 cm H2O & measured in between breaths
- What is the normal P A pressure?
- 0 cm H2O
- It oscillates between -1(inspiration) & +1(expiration) cm H2O
- What does P EL refer to & what is its normal pressure?
- It refers to stretched out lung wanting to recoil
- The pressure is +5 cm H2O (equal & opposite to intrathoracic pressure)
- What is the formula for Transpulmonary pressure?
P TP= P A – P IP
- What does transmural pressure refer to?
Pressure available to fill up the lungs
What does a (+) transmural pressure indicate?
Availability to put air into the lungs
What is the chest wall’s normal resting tone?
Outward
What do the following letters stand for; C, a, A, V, D?
- C= Content
- a= arterial
- A= Alveolar
- V= Ventilation per min
- D= Gas absorbed/expired per min
How much oxygen (mg) does 1 dL have?
20mg
What is the formula for compliance?
Compliance= Delta V / Delta P
What is the formula for Elastance?
Elastance= Delta P / Delta V
When is someone’s peak lung function?
At age 20
What is the normal VT?
500mL
What is the normal FRC?
Normal functional residual capacity is 3.0L
What volume or capacity helps keep the lungs from collapse?
RV
What makes up the FRC?
ERV= 1.5 L & RV= 1.5 L
What is the lung volume at the end of maximal expiration?
1.5L only the RV is left
What is used as a buffer when we do not breath for a bit but already exhaled?
RV
What is the total lung capacity (TLC)?
6.0 L
What makes up Vital capacity (VC)?
- IRV= 2.5 L,
- VT= 0.5 L
- ERV= 1.5 L
What is the max IRV?
2.5 L
In the supine position, which lung volume(s) do not change?
RV, VT
In the supine position, which volume(s) decrease?
ERV, FRC
In the supine position, which volume(s) increase?
IRV
How long is the normal breathing cycle?
5sec total
- Inspiration= 2sec
- expiration= 2sec
- 1 sec in between
What changes does the PA undergo during expiration?
PA goes to +1 cm H2O at 1sec then back to 0 @ the end of expiration
What is the P ER at the end of inspiration?
-7.5 cm H2O
When is the max inspiratory Delta P for the alveoli?
It is @ 1sec of the inspiratory cycle. PA pressure is @ -1 cm H2O
What makes up the PVR?
Alveolar & Extraalveolar BV’s
How does lower lung volumes affect PVR?
There is a higher increase in Extraalveolar resistance than decrease in Alveolar resistance resulting in a higher PVR
How does higher lung volumes affect PVR?
There is a small decrease in Extraalveolar resistance & big increase in Alveolar resistance resulting in a higher PVR.
Does an increase or decrease in lung volume lead to a higher PVR?
Decrease
What happens to alveolar capillaries during inspiration?
They increase in length & decrease in diameter –> higher resistance
What happens to Extraalveolar vessels during inspiration?
The negative pressure pulls on the vessel walls increasing diameter & decreasing resistance.
How much dead space volume is there?
150 mL
What is the normal RR?
12 bpm
What does V E stand for?
Total minute ventilation
What do most pulmonary tests look at?
At expired air
What action is the better option to increase O2 saturation?
Increase depth of breath rather than RR
What is the formula for calculating tidal volume?
VT= VDS + VA
Where is the apex of the lung?
It extends superior passed the 1st rib
Where is the most movement of the lungs & how much is it?
At the base & it’s about 2cm
What seals the thorax & abdomen?
The central tendon
What are the 3 diaphragm openings, anterior to posterior?
- Caval aperture
- Esophageal aperture
- aortic aperture
What is the caval aperture?
Opening for the inferior vena cava
What nerve is connected to the diaphragm?
The L & R phrenic nerves
What prevents inferior thorax movement during inspiration?
The scalene muscles
The anterior scalene muscle connects to what structures?
The 1st rib & to C3 - C6
The middle scalene muscle connects to what structures?
The 1st rib & to C3 – C7
The posterior scalene muscle connects to what structures?
The 2nd rib & to C5 – C7
What structures make up the dead space?
- Trachea
- Bronchi
- Bronchioles
- Terminal bronchioles
What structures play part in actual air exchange?
- Respiratory bronchioles
- alveolar ducts
- alveolar sacs
How many generations does the conducting zone have?
16 generations
How many generations does the respiratory zone have?
7 generations
17 - 23
What is stridor?
Noise from an obstruction in the airway
What is hyperpnea?
Hyperventilation in excess of metabolic needs
What is orthopnea?
Body position changes cause difficulty breathing
What is the difference between looking blue & looking grey?
- Blue means the Hgb does not have O2 attached.
- Grey means Hgb is low.
At what point does cyanosis occur?
When Deoxy Hgb is > 5 gm/dL
What is hypoxia?
Decreased O2 amount at tissue level
What is hypoxemia?
Decreased O2 in arterial blood
What is hyper/hypocapnia?
Excessive/deficiency of CO2 in arterial blood
Air passes through the nose or mouth, to the___, and then to the___ and then into the tracheobronchial tree.
Pharynx & larynx
What constitutes the transitional zone?
Generations 17-19, the respiratory bronchioles
What all entails an acinus?
An acinus includes respiratory bronchiole, alveolar ducts & alveolar sacs distal to a single terminal bronchiole
What are the air pathway structures after the larynx to gas exchange?
Trachea ->
bronchi ->
bronchioles ->
terminal bronchioles ->
respiratory bronchioles ->
alveolar ducts ->
alveolar sacs
What is the structural difference from bronchi and bronchioles?
Bronchioles do not contain cartilage.
Clara cells secrete what?
- Proteins (SpA, B, C & D)
- lipids
- glycoproteins
- inflammatory modulator
What are the other functions of Clara cells?
- Metabolize foreign materials
- participate in airway fluid balance
- act as progenitor cells
About how many alveoli are in a healthy human being?
~ 480 billion
What allows for interalveolar communications?
The pores of Kohn
What is the ratio of Type I to Type II cells?
1:2
Type I cells cover about___% of the alveolar surface due to__?
90-95% Due to the larger surface area
What are the purposes of Type I cells?
- They allow for easy gas exchange
- Help remove liquid from the alveolar surface by pumping sodium & water into the interstitium.
What generates spontaneous automatic breathing?
Neurons located in the medulla
What causes the resting negative intrathoracic pressure?
The mechanical interaction in opposite directions between the lung and chest wall
What is contained in the intrapleural space?
About 15-25mL of a serous liquid
During inspiration the transmural pressure difference___ & the alveoli are distended, ___ alveolar pressure?
Increases & Decreasing
Alveolar pressure is equal to intrapleural pressure + _____?
Alveolar elastic recoil pressure
What establishes the pressure gradient for air flow?
Increasing alveolar volume lowers alveolar pressure
What mechanically transmits the pressure difference across alveoli?
The alveolar septa
What are the accessory inspiratory muscles & when are they involved?
- The sternocleidmastoid, the trapezius, & vertebral column muscles.
- They are involved during exercise, coughing, sneezing or pathologic state such as asthma
The diaphragm is considered part of the___?
Chest wall
When supine the diaphragm is responsible for ___ of the air entering during eupnea? What about standing?
- Supine is 2/3 &
- Standing is 1/3
The diaphragm is innervated by the ____, which leave the spinal cord at the __ thru the ___ cervical segments?
- Phrenic nerves
- 3rd & 5th
What holds the diaphragm to the lower 6 ribs & the sternum?
By 2 crura
During eupnea the diaphragm descends __ cm & during deep breathing is descends __ cm?
1-2cm & 10cm
The scalene muscles are accessory muscles?
False, they contract during eupnea, therefore are not accessory muscles
What muscles contract during normal expiration?
None, expiration is passive
In obese people the inspiratory muscle may also contract, when?
During early part of expiration
When does active expiration occur?
During exercise, speech, signing, sneezing, coughing, bronchitis.
Contraction of the internal intercostal muscles move the ribcage___?
Downward, opposite of the external intercostals
What is the I:E ration in eupnea?
1:2 or 1:4
During inspiration the alveolar pressures ___?
Decrease (-1 cm H2O)
Compliance is the inverse of ____?
Elastance
Elastance refers to?
Tendency for something to oppose stretch & its ability to return to its original state.
Surfactant has a lesser effect on surface tension during___ due to?
- Inspiration.
- Due to movement of surfactant from interior of the liquid phase to the surface during inspiration.
Many pathologic states shift the compliance curve to the___?
Right ( for any increase in transpulmonary pressure there is less of an increase in lung volume)
Fibrosis, atelectasis & thermal injuries ___ alveolar elastic recoil?
Increase. Fibrosis decreases compliance, therefore elastance is increased
Emphysema ___ compliance due to the destruction of the ___ tissue?
- Increases
- septal tissue, which opposes lung expansion.
Compliance in obese people is ___?
- Decreased.
- Moving the diaphragm downward is much more difficult