Respiratory L7: Lectorial (Exam Questions) Flashcards
You work as a Personal Trainer in your local gym. A new female client of yours experienced a sudden onset of breathing problems during the first exercise session. You asked your client to consult her local GP. A week later your client shows you the results of her spirometry the GP has ordered. It shows an increased Residual Volume (RV) and a decreased Vital Capacity (VC).
Name TWO (2) major respiratory diseases that cause an increased RV and decreased VC.
- Asthma
- Leads to early dynamic small airway closure due to the airway resistance
- Emphysema
For asthma, briefly explain the underlying cause and mechanism for this obvious early airway closure.
- Inflammatory disease
- Inner lining of small airway becomes thicker = mucus build- up = bronchoconstriction = increased small airway resistance
- bronchoconstriction and mucus built-up in bronchioles leads to increased small airway resistance. Upon forced expiration the pressure in the small airways decreases quicker thus the equal pressure point of small airway pressure and intrapleural pressure is reached early, which results in early small airway closure, trapping more air within the alveoli hence the residual volume is increased and the vital capacity is decreased.
For emphysema, briefly explain the underlying cause and mechanism for this obvious early airway closure.
- Distraction of alveoli walls = artificial large alveoli and fewer
- Problem = less recoil of lungs = decreased transmural pressure at rest = increased intrapleural (higher than normal)
- Emphysema is a loss of lung tissue that results in a lower recoil of the lungs. This leads to a smaller transmural pressure gradient and an increased intrapleural pressure. During forced expiration the equal pressure point of intrapleural pressure and small airway pressure is reached earlier leading to an increased residual volume and decreased forced vital capacity.
In asthma, how is there an increase in small airway resistance?
Inner lining of small airway becomes thicker = mucus build- up = bronchoconstriction = increased small airway resistance
In asthma, upon forced expiration the pressure in the small airways _________ (increases/decreases) quicker thus the equal pressure point of small airway pressure and intrapleural pressure is reached _____ (earlier/later), which results in ____ (early/late) small airway closure, trapping more air within the alveoli hence the residual volume is _______ (increased/decreased) and the vital capacity is _______ (increase/decreased).
decreases; earlier; early; increased; decreased
In emphysema, what is the problem? What does that lead to?
less recoil of lungs = decreased transmural pressure at rest = increased intrapleural (higher than normal)
Emphysema is a loss of lung tissue that results in a _____ (higher/lower) recoil of the lungs. This leads to a ______ (larger/smaller) transmural pressure gradient and an _____ (increased/decreased) intrapleural pressure. During forced expiration the equal pressure point of intrapleural pressure and small airway pressure is reached _____ (earlier/later) leading to an _____ (increased/decreased) residual volume and ______ (increased/decreased) forced vital capacity.
lower; smaller; increased; earlier; increased; decreased
You work as a Personal Trainer in your local gym. A new female client of yours experienced a sudden onset of breathing problems during the first exercise session. You asked your client to consult her local GP. A week later your client shows you the results of her spirometry the GP has ordered. It shows an increased Residual Volume (RV) and a decreased Vital Capacity (VC). One aspect of the above scenario strongly indicates the diagnosis of one of the diseases.
Which aspect of the above scenario indicates which disease?
The sudden onset and the fact that breathing problems were exercise induced suggest asthma o Emphysema- doesn’t go away
Another client of yours, a very healthy and fit young male asks you if breathing pure oxygen during exercise would increase his performance. What would you suggest to him? Why?
- No benefit: Hb is fully saturated after it has passed the pulmonary circulation. Oxygen therapy would increase arterial PO2 , but because Hb is already fully saturated, the O2 content would increase only by the small amount of extra dissolved O2 in plasma.
- Healthy = no binding available
After your discussion he completes a vigorous 4-hour weight training. About 20 minutes after his weight training you see him sitting down still breathing rather heavily. Briefly explain his increased ventilation after a 20-minute resting period.
- Lactic acid built-up leads to metabolic acidosis. Heavy breathing suggests respiratory compensation of metabolic acidosis that reduces the CO2 induced [H+] thus relieving the acidosis.
- Regulate blood pH
- Type IIb muscle fibres (anaerobic) use glycolysis to produce ATP
A person who has a decreased arterial partial pressure of CO2 but normal arterial oxygen content would most likely be ________.
- Hyperventilating
- Inversely proportional
Briefly explain a cause or mechanism that would lead to a decreased Residual Volume (RV)? What does that result to?
- Pulmonary surfactant deficiency and pneumothorax. The former is often seen in premature babies leading to Infant Respiratory Distress Syndrome. Pulmonary Surfactant Deficiency increases the alveolar surface tension thus increases the overall recoil of the lung. This in turn leads to late small airway closure, hence decreased RV.
- Collapsed lung
An increased arterial PO2, decreased arterial PCO2 but a decreased blood ph indicates what?
MAYBE NOT IN EXAM
- Respiratory compensation of metabolic acidosis
- Hyperventilation
- Should be alkali but is acidic
A decreased arterial PO2 , increased arterial PCO2 but a increased arterial bicarbonate concentration and normal blood ph indicate what?
MAYBE NOT IN EXAM
- Renal compensation of respiratory acidosis brought on by hypoventilation
- Hypoventilating
- Chronic
- Normal lower (acute)
Predict the values for arterial pH, arterial PCO2 and PO2, arterial bicarbonate concentration and the P(Aa)O2 that you would expect during: Justify your predictions. (6 marks)
- acute asthma attack
- acute respiratory failure
- metabolic acidosis (eg. lactic acid build-up after exercise)
MAYBE NOT IN EXAM
What is the The CO-HB dissociation curve?
- Carbon monoxide combines with haemoglobin at the same point on the haemoglobin molecule as does oxygen.
- Furthermore, it binds with approximately 210 - 240 times as much tenacity as oxygen
How much would the oxygen carrying capacity be reduced if blood were exposed to air containing 0.1% carbon monoxide?
Affinity of CO for hemoglobin is over 200 times greater than the affinity of oxygen for haemoglobin
