Test #2 for 306 Flashcards
TEF are also commonly associated with?
Esophageal Atresia
Thyroid hormones T3 & T4
Increase the rate of production of surfactant due to increase rate of phospholipid synthesis
When is the terminal sac period?
24 weeks to birth
Primitive Pharynx>LT Groove envaginates >LT Diverticulum>Lung Bud & TE Folds>TE Folds> Laryngotracheal Tube (larynx, trachea, bronchi, Lungs) && Primitive Oropharynx & Esophagus
Formation of the Lower RESP TRACT
Cartligage of the larynx is derived from Which pharyngeal arches
4th and 6th pharyngeal arches
Other lipids in Surfactant
phosphatylinositoil sphingomyelin blah blah
Oxygen Tension
PAO2: what is available or diffusion in the pulmonary capillary
PAO2:
1- partial pressure of O2 on the alveolar gas
2-actual number of Molecules available for diffusion into pulmonary capillary
3-Sum of pressures of all gases in alveoli=760mmHg
4-Formula: Barometric pressure - partial pressure of water vapor x Fi02 in the dry air
Oxygen Tension
-Partial pressure of waterr vaopr in the lung is 47mmHG at 37 degrees when alveolar gas is fully saturated
-
- When in room air at sea level, the PAO@ is 150mmHg (760-47x.21=150mmHg)
- to get PAO2, need to also include PaCO2
- Resp quotient (R) : ratio of CO2 excretion to O@ uptake =.8
in RDS, what is deficient?
Surfactant
What do Type II Cells do?
Secrete surfactant an line the walls of the terminal sac
What are the 4 stages of Lung Development?
1-pseudoglandular 2-canalicular 3-terminal sac 4-alveolar
Minute Ventilation
Minute Vent = TV in ml x # of braths per minute or resp frequency
VE=vtxf
To whom are we thankful for being in school?
God, ourselves and our spouses
Esophageal atresia with BOTH proximal and distal TEF’s occurs more commonly in males or females?
Males (but only 1% of TEF’s)
Where is surfactant produced?
Smooth and Rough ER or type II Cells
What is the 3rd stage in lung development?
Terminal sac period
the lungs have a glassy hyaline membrane which cover the alveoli with this:
RDS Hyaline Membrane Disease
Oxygen in the blood
Forms:
1-plasma
2-Blood
Resistence
amt of pressure needed to move resp gases thru the airway at a constant flow rate
-depends on lung resistence/viscosity,
flow or airway resistence
On the left, the two secondary bronchi supply which lobe of the ling?
Upper and lower (only 2 lobes on the left)
SP-B&C
FUNCTIONAL proteins of surfactant; maintains the integrity of the cell wall
An adequate ratio of L/S is 2:1 indicating fetal lung
MATURITY
Hemoglobin
Total amounto f O2 carried by Hg depends upon
1-Concentration of the Hg (is Hg normal)
2-degree of saturation (is there adequate O2 available to have adequate saturation)
Clinical significance in low lung volumes
Compliance and FRC- indicators of severity of disease process (Low FRC=atelectasis)
- compliance decreases with worseningof disease
- compliance improves with onset of diuresis
- *diuresis-mobilization of interstitial fluid (but you can see a decrease in compliance with this)
True or False: Gastric contents cannot back up into the trachea when you have esophageal atresia with a PROXIMAL TEF?
True
Excretion of Surfactant occurs by
EXOCYTOSIS
Alveolar Minute Ventilation:
AVE= (vt-dead space) x f
what also seperates from the primitive pharynx and gives rise to Lung Buds and TE Folds?
Laryngotracheal diverticulum
Tidal Volume
6-9 ml/kg
Amount of gas drawn through nose or ETT during a single cyycle of ventilation is called a TV:
Amount of air taken in with a breath is a TV
FRC is greather than TV
What week does the development of the larynx, trachea, bronchi & Lungs occur?
4th week
Which TEF rusults in air NOT being able to to enter the distal esophagus and stomach?
Esophageal atresia with a PROXIMAL TEF (1%)
TEF’s occur due to an incomplete separation during which week of development?
4th week
In an H-type TEF, what/where is the fistula?
Between the trachea and esophagus
When, in the terminal sac period, when does the epithelial lining sac become thin causing capillaries to bulge into them?
24-28 weeks
Where is surfactant stored?
Lamellar bodies
Also present in the terminal sac period are….
Type II Secretory Cells
What is the 2nd stage of lung development?
canalicular
Insulin will inhibit surfactant production
It inhibits the production of surfactant because there is no glucose available for use; seen in IDM: inhibits glycogen breakdown; insulin results in decrease lung maturation
Tissue Resistence
40% if resistance in newborns due to
icrease pulm interstitial fluid
cc/s (RLF)
early stage RDS
Pulmonary hypoperfusion
What are some complications from an H-Type TEF?
Gastric contents can enter the trachea (lungs)
Time COnstant
TC
TC in healthy infant
TC=0.15 sec
so in 1 TC 3% of the TV will be exhaled in 0.15 secs
3 TC 3x0.5=0.45 secs
5 TC=5x0.15 =0.75 seconds for 99% of TV to be exhaled
1 TC is defined as the time needed for alveolar pressure to reach 63% of the change in airway pressure
End of 3 TC 95% of the tidal volume is discharged
Glucosteroids (Betamethosone) do what to Surfactant?
Accelerates fetal lung development; increases the availibity of glucose, increases the surfactant production by type II Cells; Increases the beta adrenergic lining cells (increasing compliance)
Inspiration is
Active
the Laryngotracheal diverticulum consists of what?
Lung buds and the TE Folds
Hemoglobin is ReSTRICTIVE
Only so much, once it’s sturated-can’t go past 100%
NON-LINEAR
Amount of HG that binds to O2 increases sharply at LOW PO2’s
Each Hg molecle binds up to 4 MOL of O2
Each GRAM of Hg carries 1.34 ml of O2
Hg will Bind more if Plasma O2 is low
How does the Laryngotracheal Groove Develop?
Outgrowth from the caudal end of the primitive phayynx
Type I Cells are used for what?
Gas exchange
What kinds of cells doe the alveoli contain?
A continious lining of TI& Type II Pneumocytes
Expiration
in normal breathing
Is a passive event
Resp muscles relax
lungs and rib cage return to a resting state
amt of gas drawn through the ETT during a single cycle of ventilation is called a TIdal Volume
Radial size of alveoli
1-Indicates how much pressure is needed to inflate the lungs
2-law of LaPlace: pressure need to inflate the lung is 2x the surface tension and is inversly proportional to the radius of the structure
P=2st/r
If radius is increased, there is less pressure needed to inflate the lung
If radius is decreased, you need more pressure to inflate the lung
In which period of lung development does the lumen of the bronchi and bronchioles become larger and more vascular?
Canalicular Period
MIGRATES to the surface of the liquid layer in order to be functional
Surfactant
True of false: in the alveolar stage of transformation, the lungs are transformed from secretory into gas exchange units?
TRUE
What is the Primary Lipid in Surfactant?
Lecithin (phosphatidylcholine)
Linear relationship of oxygen in the plasma
Increase in FiO2, there is an approximate increase in PaO2
Chemoreceptors, chest wall reflexes, lung relexes, respiratory center,
CONTROL respirations
Which bronchus is larger in the embryo and adult?
Right mainstem bronchus; it is larger and straighter
what other lipid in surfactant is unique to lung cells and is a good marker for surfactant in amniotic fluid?
Phosphatidlglycerol
PEEP or CPAP
High pressures neede to expand a non-compliant lung
-to decrease this high pressure-add PEEP or CPAP
Physilogical Dead Space
NOT AVAILABLE FOR RESP
3ml/kg
1-anatomic- portion of the air that never gets to the alveoli
2-alveolar-portion f tidal gas not perfused
3- Total of 1 & 2 = physiological dead space
4-wasted ventilation
Sphingomyelin levels remain constant
throughout gestation
What gives rise to the epithelium and glands of the larynx, trachea, bronchi & Pulmonary Epithelium?
Endodermal lining of the endotracheal groove
In Normal Breathing
INSPIRATION
Inspiration is contraction of the resp muscles
&
Enlargement of the intrathoracic space
Low lung Volumes
restrictive lung disease
1-restrictive lung disease
a) pulmonary hypoplasia (small lungs CDH)
b) surfactant defiency
c) extrinsic lung disease
d) instrisic lung restriction (liesions, PIE)
Gas Exhange
Gas echange occurs consistently due to FRC (Sizeable amount of gas in the lungs after inspiration and expiration; it is the source of ongoing gas echange
-VENTILATION in related to the concentration of CO2
FRC=30cc/kg
During which stage of lung development can the lung structures and cells support life?
During the terminal sac period at 26-28 weeks when the epithelium of the alveoli is thinned enough to allow for gas exchange (VQ Matching)
When is the terminal sac development?
24 weeks to birth
SP-A
Responsible for spreading surfactant, antioxidant, antimicrobial
Airway resistence
Low in newborn
Determined by:
flow rates
length of connecting tubing
inner diamater or airwy (wrong ETT size)
physical properties of the gas
When will the lungs increase in size due to the increase in the # of immature alveoli?
3 years of age
Type I Cells for during what stage of lung development?
The terminal sac period
TC
TC is critical when I-Time or E-Time is so short that it is insuffiient for pressure equilibration
If I-time is
If E-TIme is too short
what is formed with the Tracheoesophageal folds grow towards one another and fuse?
Trachesophageal Septum
Do the respiratory and other system remain immature during the canalicular period?
YES
When do mature alveoli form?
after birth (95% do not develop until after birth)
What week does the primitive main stem bronchus/connection of each bronchial bud beome enlarged?
5th
Respiratory Failure
RESP requires a lot of energy
1-Food Substrate-muscle fatigue from hypoglycemia
2- hypoxia
3- Elastic recoil (Passive in expiration)
a) surfactant interface
b) ability of resp muscles to relax (FRC) resting volume
Where is surfactant transported to once it is produced?
Golgi appartus
What is the first stage of lung development?
Pseudoglandular period
During the 4th week of development, the lungs divide to form what two structures?
Bronchial buds (from the primitive pleural cavity) and the BRONCHI
Ventilation
- Movement of gas convection through the airways
- Molecular diffusion into alveoli and pulmonry capillaries
- CO2 ELIMINATION is VENTILATION
O2 UPTAKE is OXYGENATION
Oxygen Tension
PaO2 is the BEST indicator of degree of O2 intake within the lungs
paO2 (oxygen concentration in arterial blood (ABG’s))
1- Partial pressure of O2
2-amountof O2 dissolved in arterial blood (plasma)
3-Expressed in units or Torr or mmHg
4-Acceptable limits in newbornd is 50-80 mmHg
During reopening of the larynx, what forms from the fold of mucus membranes?
Vocal cords
Which cells are osmophillic?
Type II Cells because they produce surfactant
Most Common TEF fistula includes what deformations? This occurs 85% of the time
Superior part of the esophagus (blind pouch) with the inferior part being joined to the trachea via a fistula
In which week does the main bronchus subdivide into 2 more bronchial buds, forming secondary bronchi?
later in the 5th week
When is the psuedoglandular period?
5-17 weeks Not possible for survival
Clinical Significance:
HYPERVENTILATION Can decease PACO2 by 20-30 mmHg- Increasing the PAO2 by the same amount
- You get a higher paO2
- Live in Denver-barometric level is 600mmHg-ingants have 1/3 less available O2 in alveeoli when breathing room air
there is an increase in the number of alveoli as well as the size of the alveoli at what age?
8 years
When/where do hypoplastic occur?
Occurs with posterolateral CDH
SP-A is the predominant protein in surfactant
YES
Why does a TEF occur?
Because there is incomplete seperataion of the trachea and espghagus
A defect/atresia with both proximal and distal TEF’s can causse gastric contents to enther the trachea?
Yep, it sure can
Surfactant
Breaks the surface tension at the air/liquid interface of alveoli; they are polar and line up
Fators that shift the curve to the right
Decrease affinity for O2
Decrease Ph
Increase PCo2
Increase H ions
What cells cover 95% f tge alveolar surfac & Are made up of Squamous epithelial cells?
Type I Pneumocytes
H-Type fistula occurs in ??? %%%%%?????
4%; people think it’s the most common type, but it is not
Expiration is
Passive
TC is RDS
Lung isn’t expanding; lung with decreased compliance will complete inflation and deflation quicker
Type II Pneumocytes are made up of what kinds of cells?
Made up of Cuboidal cells
At 24 weeks, what kind of squamous epithelial cells line the sac?
Type I Cells
As the lungs develop, what kind of pleura is acquired?
Visceral pleura
Epiglottis forms from what pair of pharyngeal nerves?
3rd & 4th
The 4th stage of lung development is the?
Alveolar Period
What is the second stage of lung development?
Canalicular Period
When do tertiary bronchi develop?
7th week
Lecithin increases from
34 weeks
On the Right, the superior bronchus will supply which lobe of the ling?
Upper (superior)
Laryngeal Muscles are derived from what?
myoblasts of the 4th & 6th pharyngeal arches
When are Type II Pneumocytes detected?
25-30 Weeks BUT potential for alveolar stability does not occur intil 3-36 weeks
The larynx is closed primarily, but it reopens again during which week of development?
10th
When does the the endotracheal groove envaginate to form the laryngotracheal Diverticulum?
end of the 4th week
In the Alveolar period, what does each resp bronchial terminates into?
thin-walled terminal sacs
where does the epithelial lining of Larynx develop from?
The cranial end of the laryngotracheal tube
Clinical uses for Peep/CPAP
corrects stelectasis
Increasess FRC
improves V/Q mismatch
Improves Pulm edema
What is the 3rd stage of lung development?
Terminal Sac Period
PEEP or CPAP
1- PEEP mechanical ventilation
2- CPAP baby is breathing spontaneouosly
-breaks the following cycle:
reduces the amount of pressure needed to ventilate; also imporved by adding surfactant
Why does Laryngeal web form?
it forms if there is an incomplete opening of the larynx in the 10th week
what findings would you expect from a TEF with esophageal atresia?
Rapid abdominal distention; the stomach and intestines rapidly fill up with air
What is the ratio of Lipids to protein in Surfactant?
9:1 90% Lipids 10% Protein
when does the canalicular period of lung development occur?
16-25 weeks of gestation
A L/S ratio of
Fetal lung immaturity
Factors that influence compliance
1-number of alveoli (if not enough, decrease in compliance)
2-surfactant
3-interstitial changes (scars/PIE/Pneumonia)
4-V/Q Mismatch
5-lung volume
CO2 moves faster than O2
Time Constant
Time Constant = resistance x Compliance
How long it takes for the lung to inflate and deflate
or
measure of how ling is takes for the lung to inflate and deflate
depends of compliance and resistanve
Concentration of surfactant in amniotic fluids occurs at a 2:1 ratio at about what week indicating lung maturity?
34-34 weeks
Terminal bronchioles divide to form smaller bronchioles during the canalicular peiord
There are 3-6 alveolar ducts at about 24 weeks
By 24 weeks, about how many orders of branches have formed and about how many respiratory bronchioles have formed?
about 17
VQ Matchiing
Capillary touhing the alveolar surface to have exchange
1-matching of ventilation and perfusion
2: ratio reflects the correlation between alveolar ventilation and capillary perfusion for lung as a whole
3-when ventilation is matched to perfusion-the ratio is 1
VQ mismatch is defective of gas exchange
95% of these cells cover the alveolar surface. These cells are interconnected by tight junctions……
Type I Cells
On the right, the inferior bronchus subdivides into two bronchi to form?
1- Middle lobe of the right lung & the other to the lower (inferior lobe)
Rib Cage in NN
1- More cylindrical than elipsoid
2-ribs more horizontal than oblique
3- Reuslts
a) Muscles are shorter
b) less mechanical advantage
c) angle of the diaghragm is different (more horizontal so air move inward rather than upward)
d) ribcage is pliable and unstable
e) retractions
Pulmonary ad systemic circulation is established in what period?
Alveolar period
When is the alveolar period?
Late fetal to 8 years of age
Factors that shift the Curve to the LEFT
Hg has an INCREASD affinity of O2
Presence of Hgf
decrease 2,3 DPG
Alkalosis
Decrease PCO2
Decrease Temp
In the pseudoglandular period:
Resembles an endocrine gland all major parts of the lung form except alveoli
Can air enter the esophagus if you have an Esophageal atresic with a PRXIMAL TEF?
No, so there is NO abdominal distention
Where does the trachea come from/differentiated from?
The distal end of the laryngotracheal tube
Surfactant is diffused/dispersed by
PROTEINS
when does adequate production of surfactant occur?
During the alveolar period
Oxygen Tension
FiO2:
1- Fraction of inspired O2
2-Measured in %%%%
3-RA has .21% O2
(In air trasnport: Altitude increases % oxygen availaible in ambient air; O2 availability is decreased because the MOLECULES are smaller and are harder to analyze
Is some respiration possible in the canalicular period?
Yes……16-25 weeks, if born between 22-25 weeks, there is a chance but some still die
Factors affecting Hg Affinity for O2
% of fetal and adult Hg
1-95% HGf
2- Hgf does not bind to 2,3 DPG
a) Result: Hgb holds onto O2 tightly
b) Left shift in Oxyhgb Curve
