Respiratory

Question 1

Lung development
1) respiratory tract is derived from ___
2) what first branches from esophagus to form the lungs?
3) does this arise from forgot, Midgut, or hindgut

Answer 1

1) Endoderm
2) Ventral Bud
3) Foregut

Question 2

Vascular Supply
1) which aortic arch does the pulmonary vasculature form from?
2) where do the bronchial arteries come from? What did they supply?
3) how do pre-Acenar arteries develop? When are they complete?
4) how do intra-Acenar arteries develop? When are they complete?

Answer 2

1) sixth aortic arch
2) aorta to the conducting airways, visceral, pleura, connective tissue
3) angiogenesis (16 weeks)
4) vasculogenesis (alveolar development to 8-10 years)

Question 3

Alveolarization
1) what phase does this occur? (Timeline)
2) how many alveoli at term? Adult?
3) what enhances alveolarization?
4) what delays alveolarization?

Answer 3

1) alveolar phase (36 weeks to 8 years)
2) 50 – 150million -> 200–600 million
3) vitamin a and thyroxine
4) postnasal steroids, oxygen, malnutrition, ventilation, insulin, inflammation

Question 4

Lung development
List the stages of lung development and gestational age

Answer 4

Embryonic (0–5)
pseudoglanular (5–15)
canalicular (15–25)
Sacular (25–35)
Alveolar (36+)

Question 5

Embryonic
1.) structures?
2.) developmental abnormalities?

Answer 5

-Ventral bud, bronchi, five branches/lobes (“5 branches by 5 weeks”)
-Pulmonary vasculature from 6th aortic arch
-laryngeal cleft, tracheostenosis, tracheoesophageal fistula, bronchogenic cyst

Question 6

Pseudoglandular
1) structures?
2) developmental abnormalities

Answer 6

Branching up to terminal bronchi
Bronchopulmonary epithelium -> amniotic fluid
Pneumocyte precursors
Vasculature (artery/veins)
Separation of thorax/peritoneal (7wk)

Branching abnormalities, CDH, CLE, CPAM, pulmonary lymphangiectasia

Question 7

Cannulicular
1) structures?
2) developmental abnormalities?

Answer 7

-Terminal bronchioles/respiratory bronchioles
-Type two-> type one pneumocytes
-Viable lung at 25 weeks

Pulmonary hypoplasia, surfactant deficiency, alveolar capillary dysplasia

Question 8

SACCULAR
1) structures?
2) developmental abnormalities?

Answer 8

-alveolar ducts
-Complete bronchial division
-Gas exchange = alveolar/capillary membrane

2) pulmonary hyperplasia, surfactant deficiency

Question 9

ALVEOLAR
1) structures?
2) developmental abnormalities?

Answer 9

1) alveoli
-Microvasculature

2) surfactant deficiency, CLE, PHTN

Question 10

PNEUMOCYTES
1) percent surface area of alveoli?
2) which secrete surfactant?
3) which is progenitor cell?

Answer 10

1) I = 90% II = 10%
2) type 2
3) type 2

Question 11

FETAL LUNG FLUID
1) how much volume? Equal to what on PFT?
2) production rate near term?
3) how is Cl- transported and pulmonary epithelia?
4) what inhibits fetal lung fluid production?

Answer 11

1) 20–30 ML/KG; FRC
2) 4–5, ML/KG/HR
3) actively on basal side
4) Epi (delivery stress), B-adrenergic agonists

Question 12

ABSORPTION OF FLF
1) prior to birth, function of respiratory epithelium changes from _____ secreting to _____ absorbing.
2) FLS decreases by ___, prenatally, ___ during active labor and ___ postnatal.
3) why is it helpful to have fluid in lungs at birth?

Answer 12

1) chloride, sodium

2) 1/3

3) P~T/r ⬆️ radius of airways allows for a lower pressure to overcome surface tension

Question 13

SURFACTANT
1) what is the largest composition?

2) what percentage is surfactant proteins

Answer 13

1) 50% disaturated Phosphatidylcholine

2) 8%

Question 14

SURFACTANT
1) chromosome for SP-A
2) chromosome for SP-B
3) chromosome for SP-C
4) chromosome for SP-D

Answer 14

1) 10
2) 2
3) 8
4) 10

Question 15

SURFACTANT
1) which is the most abundant?
2) hydrophobic?
3) express last (early third trimester)
4) assist w/ tubular myelin formation?
5) promotes surface absorption of phospholipid?
6) aids in host defense?

Answer 15

1) SP-A
2) SP-B, C
3) SP-D
4) SP-A, B
5) SP-B, C
6) SP-A, D

Question 16

SURFACTANT
1) which SP has no known mutations?
2) which homozygotes deficiency is autosomal recessive? Timeline of symptoms?
3) which is autosomal dominant? Timeline?

Answer 16

1) SP-A, D
2) SP-B @birth
3) SP-C months ➡️ interstitial lung disease

Question 17

SURFACTANT
1) what is the most common known genetic cause of surfactant deficiency? Inheritance?
2) mechanism of action of this protein?
3) timeline?

Answer 17

1) ATP-binding Cassatt member A3 deficiency (ABCA3 deficiency); autosomal recessive

2) assist with transport of lipids; deficiency lacks DPPG, and PG. Decreased lamellar bodies.

3) soon after birth to childhood

Question 18

SURFACTANT
1) ___ % of secreted surfactant is recycled

2) what is the turnover time?

Answer 18

1) 95%

2) 10 hours

Question 19

SURFACTANT
what is Survanta made from and what does it contain?

Answer 19

Minced bovine long
SP-B and C (small amounts.)
No SP -A

Question 20

SURFACTANT
What is infasurf and what does it contain?

Answer 20

Bovine lung lavage

SP-B, C
No SP -A

Question 21

SURFACTANT
What is Curosurf made from and what does it contain?

Answer 21

Minced porcine lungs

SP-B, C
No SP-A

Question 22

SURFACTANT
What is Alveofact made from and what does it contain?

Answer 22

Bovine lung lavage

SP-B, C
No SP-A

Question 23

SURFACTANT
Laplace’s Law

Answer 23

P=2T/r

“LaPressure’s Law”
Pressure is directly proportional to ST and indirectly to radius.

Question 24

CONTROL OF BREATHING
Boyles Law

Answer 24

P1V1=P2V2

Question 25

APNEA
1) define apnea
2) define periodic breathing

Answer 25

1) no airflow for >20 seconds
2) 3 respiratory pauses with more than 3 sec between for up to 20 seconds

Question 26

Ventilation
Ideal ventilation:perfusion

Answer 26

Va/Q should = 1
Anything else = VQ mismatch = hypoxemia

Question 27

VENTILATION
ventilation equation

Answer 27

Va= (tidal volume - dead space) x RR

Question 28

MECHANICS
1) resistance equation
2) most respiratory resistance

Answer 28

R = change in pressure (cmH2O / change in flow(L/s)

Chest wall (25%), airway (55%), lung tissue (20%)

Question 29

What part of the respiratory system has the most resistance?

Answer 29

About 50% of airway resistance is due to nasal resistance

Question 30

Poiseuille’s Law

Answer 30

Flow = [change in pressure x constant x (radius)4] / [8 (length X viscosity)]

Radius to the 4th power

Question 31

What happens to the resistance if the diameter of an ETT increases from 2 to 4 mm

Answer 31

If the diameter goes from 2 to 4 than the radius will increase from 1 to 2. And the resistance will be 16 times less because resistance is indirectly proportional to r ^ 4.

Question 32

Compliance equation

Elastance equation

Answer 32

C=changing vol / changing pressure
-Compliance is the slope of the volume pressure curve

E= changing pressure / changing vol
-elastance is inverse of compliance

Question 33

How does compliance differ from neonates to adults?

Answer 33

Greater chest wall compliance because bones are more Cartlidge and soft and compliant compared to hard adult ribs.

Question 34

1) How does compliance differ from premature to term infants?
2) How does RDS change compliance?

Answer 34

1) premature infants, have more compliant lungs

2) sentence with RDS have stiffer lungs. Flat volume pressure curve. Less compliant lungs

Question 35

MECHANICS
What happens to compliance at both high and low lung volumes?

Answer 35

Compliance decreases because very small volume changes require large pressure changes.

Question 36

What are disease states that lead to low FRC, and high FRC

Answer 36

1) low: RDS-> atelectasis and collapse

2) high: MAS, chronic lung disease, using excessive vent pressures

Question 37

MECHANICS
Define “time constant”

Time constant equation

Answer 37

How quickly the lungs can empty.
Also, how long it takes for alveolar and proximal airway pressure to equilibrate.

TC= resistance x compliance 

Question 38

MECHANICS
One time constant = ____% volume
Two time constant
Three time constants
3-5 time constants

Answer 38

63%
86%
95%
3-5: necessary to allow adequate time for inspiration and expiration

Question 39

MECHANICS
1) Healthy, newborn time constant?
2) RDS
3) CLD

Answer 39

1) 0.09-0.15
2) lower 0.05 (decreased lung compliance, and mildly increased airway resistance)
3) higher >0.15 (decreased lung compliance, and markedly, increased airway resistance

Question 40

MECHANICS
What is increase in neonates compared to adults?

Answer 40

Respiratory rate
Residual volume
Minute ventilation (TV x RR)
Alveolar ventilation
Chest wall compliance (soft compliant ribs)
Lung tissue resistance (more dense)
Oxygen consumption

Question 41

MECHANICS
What is decreases in neonates compared to adults?

Answer 41

Tidal volume
Total lung capacity
Inspiratory capacity
Vital capacity
Time Konstant
Lung compliance (stiffer lungs)
Muscle strength

Question 42

MECHANICS
What is the same in neonates and adults?

Answer 42

 Dead space
Functional residual capacity

Question 43

PATH
Sequestration vs CPAM

Answer 43

Sequestration: “sequestered in time out” not functioned, not connected to bronchial tree, systemic circulation, most likely to cause respiratory distress

CPAM: fed by Pulm circulation,

Both unilateral, both regress in utero.

Question 44

OXYGEN
1) Define paO2

2)Each hemoglobin contains ___ sites that combine to oxygen

3) define O2 sat

Answer 44

1) Partial pressure of oxygen dissolved in the plasma of arterial blood. (Not bound to Hgb)

2) 4 Fe++ Heme

3) % hgb O2 binding sites that are saturated with O2.

Question 45

OXYGEN
1) O2 content equation

Answer 45

1) O2 con= bound to hgb + dissolved

= (1.34 x Hb x O2sat) + (0.003 x paO2)

Question 46

CO2
1) how is majority transferred in blood

Answer 46

1) bicarb ions (70%) vs 10% dissolved

Question 47

BPD
classification

Answer 47

mild: 02 at 28d + room air at 36 wks
Moderate: 02 at 28D + < 30% at 36WKS
Severe: 02 at 28D + >= 30% at 36WKS or CPAP

Question 48

Factors associated with accelerated long maturation and surfactant production

Answer 48

1) chorioamnionitis
2) chronic maternal hypertension
3) hemoglobinopathy
4) incompetent cervix
5) IUGR
6) maternal cardiovascular disease
7) placenta, infarction
8) pregnancy, induced, hypertension
9) prolong rupture of membranes 

Question 49

Pulsus paradoxus occurs when the <increase/decrease> in <systolic/diastolic> blood pressure during <inspiration/expiration> is exaggerated and > ___mm Hg.

Answer 49

decrease in systolic blood pressure during inspiration is exaggerated and > 10 mm Hg.

Question 50

Which surfactant protein is not associated with human disease.

Answer 50

A, B, C are associated with human disease. D Does not

Most critical: b chromosome 2 (b is the second letter), c on chromosome 8 causes disease later.

A tubular myelin formation.

8% of surfactaht.

Question 51

La places law

Answer 51

P = 2T/r