Respiratory Flashcards
When and where does the lung bud develop from
What are the stages of lung development and when do they occur
When is surfactant formed
Week 4 from the endoderm Embryonic- Pseudoglandular- from 6 weeks Canalicular- from 16 weeks Saccular- from 24 weeks Alveolar- from 36 weeks
What forms at each stage of lung development
Embryonic- bronchial buds Pseudoglandular- bronchioles Canalicular- terminal sacs Saccular- surfactant Alveolar- alveoli
What shifts the o2 affinity curve left?
What does this do to oxygen affinity Examples?
Increased affinity for o2
Fetal hb
LESS h, temp,co and 2,3 DPG
What shifts the o2 dissociation curve right
What does it indicate
2 examples
Increased affinity to o2
Raised H, CO 2,3 DPG and temp
Adult hb and sickle cell
What is the role of 2,3 DPG
when it increases what does it do
How does it correlate to the o2 binding curve?
Controls o2 release from hb
Lowers affinity to o2
Increases- reduces affinity- shifts curve right
Lowered- increases affinity- shifts curve left
What process causes most toxic effects from carbon monoxide poisoning?
Reversible binding to cytochrome A3
From bottom to top what 4 volumes are seen in the spirometry curve
What capacity do all 4 make up?
Reserve vol Exp reserve Tidal vol Insp reserve Total lung capacity
What makes up the forced vital capacity (3 volumes)
IRV
TV
ERV
What makes up the functional residual capacity?
What does it signify?
Reserve vol
Exp reserve vol
Everything left after a normal breath out
What is changed more in obstructive disease; Inspiration or expiration
How do the volumes and capacities change
How does FEV1 change. How and why does this change the ratio?
Expiration becomes poor- air trapping Increased RV and ERV increased FRC and TLC Reduced FEV1 FEV1 reduces more than fvc therefore ratio decreases
Why can spirometry not diagnose restrictive disease reliably?
Cannot measure the RV therefore can’t measure TLC
How does the spirometry flow loop change in obstructive disease
Concave curve in exp.
normal curve in insp.
moves slightly left
What changes in restrictive disease
How does the ratio change
All volumes decrease
Increased or normal as all volumes and FEV1 reduce in proportion
In central/small airways obstruction how does a fixed obstruction look
How would a variable extrathoracic defect change the curve and why? Give an example
How would a variable intrathoracic curve look and why? Give an example
Boxed shaped curve- both insp and exp change
Extrathoracic airways have the smallest lumen in inspiration- flattening of the insp curve.
Vocal cord dysfunction
Intrathoracic have the smallest volume on exp- flattening of the exp curve.
Tracheomalacia
What is FEF 25-75
What does it indicate
What value is abnormal
Average flow rate in the middle of the FVC
Medium airway disease
<66%
What two shapes will you see in a normal flow volume curve
Will the upper or lower bit be inspiratory or expiratory
Triangle above a semi circle
Upper- exp
Lower- Insp
How does the spirometry flow loop change in obstructive disease
How does it change in restrictive disease
Moves left, scalloped exp portion
Generally smaller
What object does fixed upper airway dysfunction look like on a flow volume curve. What causes it
Post box
Tracheal stenosis
How does a variable intrathoracic obstruction look on a flow volume loop?
What causes it
Flattening of the exp curve
Tracheomalacia or foreign body
How does a variable extrathoracic obstruction look on flow volume loop?
Give an example
Flattened insp curve
Laryngomalcia or vocal cord palsy
What 2 volumes make up the inspiratory capacity
Reserve volume
Insp reserve volume
What happens FEV1:FVC ratios in obstructive disease and restrictive disease
Obstructive- FEV1 reduces more than fvc therefore ratio reduces
Restrictive- both reduce so ratio is normal or increased
What would be seen on spirometry with poor technique
Everything reduces in proportion
Which gene in CF is potentially treated
What class of defect is it
What is the medication
G5116D
Class 3
Ivacaftor
