Regulation of breathing Flashcards
Explain the process of normal quiet inhalation when the Dorsal respiratory group is active
-Diaphragm contracts and external intercostal muscles contract during their most active phase
-Ribcage moves upwards and outwards
-Pressure decreases inside the lungs to below atmospheric pressure, drawing air in from the environment
Explain the process of normal quiet exhalation when the Dorsal respiratory group is inactive
-Diaphragm relaxes and external intercostal muscles becomes less active and relax, followed by elastic recoil of lungs
-Ribcage is pulled downwards and inwards
-Pressure increases inside the lung to above atmospheric pressure, forcing air out into the environment
Explain the process of forceful inhalation
-Dorsal respiratory group (DRG) activates the ventral respiratory group (VRG)
-Diaphragm contracts and external intercostal muscles contract during their most active stage
-Accessory muscles of inhalation contract
=forceful inhalation
Explain the process of forceful exhalation
-Ventral respiratory group causes accessory muscles of exhalation to contract
=forceful exhalation
What are the 2 principal areas of the respiratory system?
-The medullary respiratory centre in the medulla oblongata
-The pontine respiratory centre in the pons
What area sets the basic rhythm of respiration?
The inspiratory area in the medualla oblongata
What can respirations be modified by?
-cortical influences
-chemoreceptors
-limbic system stimulation
-proprioceptor stimulation
-temperature
-pain
-irritation of airways
-inflation reflex
What is compliance in respiratory?
-ease with which the chest wall and hence lungs can stretch/ expand
-in the lung determined by alveolar surface tension and chest wall recoil
-by 8 years old chest wall should be compliant
What is airways resistance?
-determined by length, radius and cross section of airways and density viscosity and velocity of gas
-resistance increases as the diameter of the airways decreases as found with the bronchoconstriction, oedema and increase in mucous
What is work of breathing?
-determined by muscular effort required for breathing
-usually WOB requires low effort but increases with disease process resulting in increased consumption and metabolic demand
What happens in external respiration?
-gas exchange between blood and lungs
-the movement of gases is always from an area of greater pressure to one of the lesser pressure
-pressure resulting from any gas is called partial pressure
-the p in PO2 means partial pressure
What happens in internal respiration?
The process of exchanging oxygen and carbon dioxide between the body’s cells and blood
What is acidosis?
-When carbon dioxide (CO2) levels in the blood are high, it can lead to acidosis, a condition where the pH of the blood falls below 7.35.
-This happens because high CO2 levels cause a rise in the concentration of H+ ions in the bloodstream, which lowers the pH.
