Respiratory Physiology Flashcards
What are the three respiratory functions?
Ventilation
Oxygen utilisation
Gas Exchange
What are the two steps of breathing
Ventilation
Oxygenation
What is the conducting zone?
Areas of the respiratory system that moves air- the mouth, nose, pharynx, larynx, trachea, primary bronchi, all branches of bronchioles up to and including the terminal bronchioles
What are the functions of the conducting zone?
Warm and humidify air, filtration, cleaning, transport
Where in the lungs is there an improved ventilation to perfusion ration?
Lung bases
Why does more perfusion occur towards the base of the lungs?
High concentration of capillaries surrounding respiratory alveoli
What is the role of surfactant?
Dissolve within water to break surface tension to allow alveoli to inflate
Which lung cells produce surfactant?
Type 2 alveolar cells/ pneumocytes
What is anatomical dead space?
Anatomical dead space is air contained within the conductive airways of the respiratory system, that does not enter gas exchange regions
What are the inspiratory muscles for respiration?
External intercostal
Sternocleidomastoid muscles
Anterior serration
Scaleni
How is pulmonary function assessed?
Spirometry
What is tidal volume?
The volume of gas inspire or expired in an unforced respiratory cycle
What is inspiratory volume?
The maximum volume of gas that can be inspired curing forced breathing in addition to tidal volume
What is expiratory reserve volume?
The maximum volume of gas that can be expired during forced breathing in addition to tidal volume
What is residual volume?
The volume of gas remaining in the lungs after maximum expiration
What is vital capacity?
The maximum amount of gas that can be expired after maximum inspiration
What is inspiratory capacity?
The maximum amount of gas that can be inspired after a normal tidal expiration
What is functional residual capacity?
The amount of gas remaining in the lungs after normal tidal expiration
What does Fick’s law say about movement of gases?
Gas will move from areas of high concentration to a low concentration. The rate of diffusion is proportional to the concentration gradient
Where in the brain are the respiratory centres?
The brain stem
What is the Hering-Breuer inflation reflex?
Baroreceptors within lung tissue detect stretching and generate impulses to the medulla to depress the inspiration centre
Explain chemical regulation of breathing
CO2 diffuses from blood into the CSF, dissolving in water to form carbonic acid. This lowers PH and stimulates central chemoreceptors to send impulses to the respiratory centre
What is the average PH of arterial blood
7.4
Why does oxygen move from alveoli into the blood?
The partial pressure of O2 within the alveoli is 105mmhg, within the capillaries it is 100mmhg. Oxygen follows the concentration gradient so moves into blood
