Lungs: Fine-tuning Flashcards
What happens to pH of the blood as it passes through systemic capillaries
It decreases
How is the efficiency of O2 transmission to cells affected as blood passes through systemic capillaries
The oxygen dissociation curve shifts which causes MORE O2 to be delivered to the cells
Is the airway involved in the swallowing reflex and vomiting reflex. If so, how?
They are:
Swallowing reflex - Respiration is INHIBITED to prevent aspiration of food
Vomiting Reflex - Oesophagus relaxes and the glottis is CLOSED
What happens to the amount of surfactant as the lungs inflate and why is this the case
The amount of surfactant decreases to prevent OVERINFLATION
What happens to the amount of pulmonary surfactant when blood flow is interrupted
The amount of surfactant decreases when pulmonary blood flow is interrupted as this occlusion causes the lungs to collapse
How does lung residual volume vary as people age?
The lung residual volume INCREASES
Tidal Volume DECREASES
How does the lung volume level at which small airways start to close during expiration change with age
Increases with age
At what stage of inspiration is INTRAPLEURAL PRESSURE is lowest?
End of inspiration
At what stage of inspiration is INTRAPULMONARY PRESSURE lowest?
mid-inspiration
At what stage of inspiration is INTRAOESOPHAGEAL PRESSURE lowest?
end of inspiration
An increase in CO2 uptake causes an equal increase in HCO3- and H+. True or False?
False
H+ is largely buffered by haemoglobin so it doesn’t enter the blood while HCO3- is
What has the highest conc in arterial blood, CO2 or O2
CO2
What is usually bigger, the rate of perfusion or the rate ventilation
Rate of perfusion
What receptors bring about bronchoconstriction
M3
Describe the hering-breuer inflation reflex
- Stretch receptors found throughout the bronchi and bronchioles send impulses down the vagi to the DRG when stretched
- Stops APs being transmitted to inspiratory muscles, causing them to RELAX
Describe the flow-volume curve
Flow into the lungs increases as volume increases initially until we reach a peak called the peak expiratory flow. The flow rate begins to decrease as we reach the end of inspiration
We then reach FVC
Flow reaches a lower peak during inspiration (the peak inspiratory flow)
What does the volume-time curve of a spirometer show
FEV1 + volume of air breathed out during maximal exhalation
What kind of receptor is M3
G-coupled
What do M3 receptors cause in the bronchioles
Increased intracellular Ca2+ - BRONCHOCONSTRICTION
What do M3 receptors cause in the endothelium
Increased release of NO - VASODILATION
What binds to beta-2 receptors
adrenaline
When is beta-2 receptor binding adrenaline released
When noradrenaline binds to the adrenal glands - BRONCHODILATION
When is compliance of lung greatest (spirometer wise)
Within the normal range of the tidal volume
What happens to the rate of ventilation at high altitudes
Increases
