Effects of Anaesthesia on Lung Function Flashcards
Regarding the humidification of inspired gas during normal resting nose breathing:
It is made more efficient by turbulent gas flow caused by the nasal turbinates
True. This results in better mixing of air and water vapour from airway lining fluid.
Regarding the humidification of inspired gas during normal resting nose breathing:
It is not complete until inspired gas reaches the small bronchi
False. It is complete when gas reaches the trachea in quiet breathing.
Regarding the humidification of inspired gas during normal resting nose breathing:
It occurs due to evaporation of water from the mucous layer of airway lining fluid
True. The mucous layer is the most superficial and contains abundant water for evaporation.
Regarding the humidification of inspired gas during normal resting nose breathing:
It is facilitated by the viscoelastic properties of mucin
False. The viscoelastic nature of mucins has no effect on water evaporation.
Regarding the humidification of inspired gas during normal resting nose breathing:
It influences the depth of the periciliary layer of airway lining fluid
False. The depth of the periciliary layer remains constant irrespective of the humidification role of the airway lining fluid.
Which of the following substances are inactivated on passing through the pulmonary circulation?
A. Histamine
B. Lidocaine
C. Bradykinin
D. Adrenaline
E. Prostaglandin D2
A. Incorrect. Endothelial cells have no uptake system for histamine.
B. Correct. Any basic drug is inactivated.
C. Correct. This is rapidly metabolised by endothelial cell surface bound angiotensin converting enzyme.
D. Incorrect. Endothelial cells have no uptake system for adrenaline.
E. Correct. Active metabolism occurs on the cell surface.
Regarding the cilia of the respiratory epithelial cells:
Cilia beat within the mucous layer of the airway lining fluid
False. Cilia can only beat in the low-viscosity periciliary layer.
Regarding the cilia of the respiratory epithelial cells:
Cilial activity is impaired by inhaled anaesthetic agents
True. All inhaled anaesthetic agents slow cilial beat frequency.
Regarding the cilia of the respiratory epithelial cells:
Cilia move the airway lining fluid along the airway at 10 mm/s
False. Cilia move at 4 mm/s.
Regarding the cilia of the respiratory epithelial cells:
The recovery stroke of a single cilium beat occupies a majority of the total time
True. 75% of the time, the cilium is recovering from the effective stroke.
Regarding the cilia of the respiratory epithelial cells:
Cilia tips only reach into the mucous layer during the effective stroke of each beat
True. This is how the cilium grips the mucus to move it along.
Is the following compound present in airway lining fluid to facilitate defence against inhaled pathogens?
Immunoglobulin IgM
Incorrect. IgA is present in the upper airway and IgG is found in the lower respiratory tract.
Is the following compound present in airway lining fluid to facilitate defence against inhaled pathogens?
Defensin peptides
Correct. Defensins are natural antibiotics present throughout the respiratory tract.
Is the following compound present in airway lining fluid to facilitate defence against inhaled pathogens?
Surfactant protein A
Correct. Surfactant protein A in the alveoli has immunological activity.
Is the following compound present in airway lining fluid to facilitate defence against inhaled pathogens?
Elastase
Correct. This is a protease enzyme present in mucous that is active against pathogens.
Is the following compound present in airway lining fluid to facilitate defence against inhaled pathogens?
Angiotensin converting enzyme
Incorrect. This is only present in pulmonary circulation and has no immunological role.
Does the following statement support the suggestion that the lung is an endocrine organ?
The lung converts angiotensin I into angiotensin II
False. Angiotensin is not produced in the lung.
Does the following statement support the suggestion that the lung is an endocrine organ?
Pulmonary endothelium secretes nitric oxide which via its association with haemoglobin exerts an effect on systemic capillaries
True. A substance secreted into the blood by the lung exerts a physiological effect elsewhere in the body.
Does the following statement support the suggestion that the lung is an endocrine organ?
Histamine secretion by the lung in response to inhaling an allergen causes bronchospasm
False. This is a local paracrine response.
Does the following statement support the suggestion that the lung is an endocrine organ?
Pulmonary endothelium completely inactivates circulating adrenaline
False. Adrenaline is not produced by the lung.
Does the following statement support the suggestion that the lung is an endocrine organ?
Fall in blood pressure secondary to secretion of prostaglandins following inhalation of an inhaled allergen
False. An endocrine effect is physiologically beneficial, while this one is a pathological response.
Is the following statement concerning catecholamine metabolism by the pulmonary circulation correct?
It occurs by the action of monoamine oxidase in the endothelial cells
True. MAO is abundant in endothelial cells.
Is the following statement concerning catecholamine metabolism by the pulmonary circulation correct?
It results in complete clearance of noradrenaline from the circulation
False. Only one-third is removed due to a lack of a specific uptake mechanism for noradrenaline.
Is the following statement concerning catecholamine metabolism by the pulmonary circulation correct?
It is important for removing circulating histamine
False. Histamine is not taken up into endothelial cells.
Is the following statement concerning catecholamine metabolism by the pulmonary circulation correct?
It results in complete clearance of 5-hydroxytryptamine from the circulation
True. A very specific uptake mechanism exists.
Is the following statement concerning catecholamine metabolism by the pulmonary circulation correct?
It is dependent on highly specific uptake mechanisms on the endothelial cell surface
True. The metabolic enzymes are completely non-specific, so selective metabolism depends only on the molecular uptake systems.
