10b: Resp Flashcards
Respiration is possible after which week of embryonic development?
Week 25 - end of canalicular stage
incompatible with life before that
Errors at (X) stage of lung development can lead to tracheoesophageal fistula
X = Embryonic (weeks 4-7)
By the end of the embryonic stage of lung development, the (X) (bronchi/bronchioles/alveoli) have formed
X = tertiary (segmental)
bronchi
By the end of the pseudoglandular stage of lung development, the (X) (bronchi/bronchioles/alveoli) have formed
X = terminal
bronchioles
(Weeks 5-17)
The respiratory bronchioles and alveolar ducts are formed by (X) stage of respiratory development.
X = Canalicular (Weeks 16-25)
Alveolar ducts form terminal sacs in which stage of lung development?
Saccular (Week 26-birth)
Pneumocytes develop in which stage of lung development?
Saccular (Week 26-birth) - mature levels not achieved until around week 35
The terminal sacs become adult alveoli in (X) stage of lung development. What is the key feature that distinguishes the two structures?
X = Alveolar (Week 36-8 years old)
Secondary septation (adult alveoli) versus primary septation (terminal sacs)
CXR of newborn shows discrete, round, sharply defined density in medial 1/3 of lungs. What is the likely congenital malformation?
Bronchogenic cyst (fluid-filled; air-filled if infected)
Pulmonary surfactant is a complex mix of (X). (Y) is the most important of these
X = lecithins Y = dipalmitoylphosphatidylcholine (DPPC)
List the potential complications of neonatal oxygen supplementation for respiratory distress
“RIB”
- Retinopathy of prematurity (hyperoxia, high VEGF/neovascularization, retinal detachment/blindness)
- Intraventricular hemorrhage
- Bronchopulmonary dysplasia
Screening test for fetal lung maturity:
Measure phospholipid content of amniotic fluid
Lecithin/Sphingomyelin ratio (L/S ratio) in amniotic fluid; greater than 2 is healthy, less than 1.5 predictive of NRDS
Anatomic dead space refers to air in which structure(s)?
Conducting zone of respiratory tree (no gas exchange) = nose up to terminal bronchioles
(X) structure(s) are lost when bronchi become bronchioles
X = cartilage and goblet cells
Transition from (X) epithelium to (Y) epithelium occurs at the (Z) bronchioles
X = pseudostratified columnar (ciliated) Y = cuboidal (ciliated; lose cilia in respiratory bronchioles) Z = terminal
T/F: Mucociliary clearance remains the primary clearance mechanism throughout the entire conducting zone of lung
True (alveolar macrophages clear debris in resp zone)
Least resistance in airway/respiratory tree is seen at level of (X) (bronchi/bronchioles/alveoli). And highest resistance?
X = terminal
Bronchioles (large numbers in parallel)
Med-sized bronchioles (due to turbulent flow)
RALS (“right anterior, left superior”) refers to (X) relationship to (Y) in lungs
X = pulmonary artery Y = bronchus
In hilum
The carina is sandwiched between which two key structures in thorax?
(Carina is bifurcation of trachea into R and L bronchi)
Anterior: ascending aorta
Posterior/lateral: descending aorta
T/F: Aspirating peanut while upright or supine will both cause it to enter R lower lobe
False - if supine, R upper lobe probably
List the three main structures perforating the diaphragm and at which levels they do so
- IVC (T8)
- Esophagus (T10)
- Aortic hiatus (T12)
“I(VC) 8 10 eggs (esophagus) at (aorta) 12”
The IVC as well as (X) perforate diaphragm at T(8/10/12).
X = right phrenic n
T8
The Esophagus as well as (X) perforate diaphragm at T(8/10/12).
X = vagus n (CN 10)
T10
The Aorta as well as (X) perforate diaphragm at T(8/10/12).
X = azygos vein, thoracic duct
T12
“At T-1-2 is the red, white, and blue”
The trachea bifurcates at which SC level?
T4 (biFOURcates)
The common carotid bifurcates at which SC level?
C4 (biFOURcates)
Functional residual capacity calculation:
RV+ERV (volume of gas in lungs after normal expiration)
Vital capacity calculation:
IRV + TV + ERV (max volume of gas that can be expired after max inspiration; also equals TLC - RV)
Aging changes: (increased/decreased) chest wall compliance, (increased/decreased) lung compliance, and (increased/decreased) (RV/TLC).
Decreased (calcification/stiffening of ribs)
Increased (loss of elastic recoil)
Increased RV; no change in TLC
Physiologic dead space equation
VD = VT*((PaCO2-PeCO2)/PaCO2)
“Taco, Paco, Peco, Paco”
VT= Tidal V
PeCo2 = expired air PCO2
Physiologic dead space refers to air in:
Conducting zone (aka anatomical dead space) + alveolar dead space (primarily in apices of lungs)
T/F: Physiologic dead space is much greater than anatomical dead space in normal lungs
False - the two are approximately equal in healthy lungs (barely any physio dead space), but physiological dead space may be greater if V/Q defect
At (X) lung volume, airway/alveolar pressures are zero and intrapleural pressure is (pos/zero/neg).
X = FRC (note: inward pull of lung balanced by outward pull of chest wall at this volume)
Neg (about -5 cm H2O)
T/F: Alveolar transmural pressure is always positive, regardless of volume of air in lungs.
True - perpetual collapsing force on lungs
Deoxy Hgb has (high/low) oxygen affinity
Low (taut form;promotes release/unloading of O2)
Oxy Hgb is relaxed form and has high affinity for O2
Mutations that alter (X) in Hgb will cause lower 2,3-BPG affinity
X = 2,3-BPG binding pocket positive charge
2,3-BPG is negatively charged, so mutation in binding pocket that decreases positive charge will decrease affinity (ex: familial erythrocytosis)
The phrenic nerve carries pain fibers from which parts of (visceral/parietal) pleura?
Parietal (diaphragmatic and mediastinal; the rest is via intercostal nerves)
Visceral pleura does not have pain fibers
Oxidized form of Hgb is (X). It binds O2 (more/less) readily and patient presents with which unique features?
X = MetHgb (Fe3+ state)
O2 less readily (but high affinity for CO)
Cyanosis (dusky skin) and chocolate-colored blood