airflow and gas exchange Flashcards
what is the normal respiratory rate
20-30brpm
what is the normal respiratory rate in horses
10-12brpm
eupnoea
normal breathing
tachypnoea
increased respiratory rate
hyperpnoea
increased respiratory depth
dyspnoea
increased respiratory effort
apnoea
absence of breathing
what is involved in breathing
muscle contraction
diaphragm
external intercostal muscles
internal intercostal muscles
abdominal wall muscles
what is inspiration
diaphragm and external intercostals contract
what is expiration
usually passive can be active in some species during exercise where internal intercostals and abdominal muscles contract
what is compliance
degree to which a decrease in transpulmonary pressure leads to an increase in volume of the lung
what does compliance depend on
elasticity of lungs and thoracic cage
surface tension in the alveoli
why are alveoli lined with fluid
to facilitate dissolution and diffusion of gases
what creates surface tension
water molecules form hydrogen bonds at a water-air interface
what does surface tension resist
expansion of the lungs
what does surfactant do
acts to reduce surface tension of the fluid film lining the alveoli
what does the pressure inside an alveolus depend on
its radius and the surface tension inside it
what is airway resistance dependent on
radius and length of tube and viscosity of the substance travelling through it
what is the correct exchange of gases reliant on
ventilation and perfusion of the alveolus
hypocapnia
hyperventilation will cause excess loss of co2 leading to a drop in PaCO2
what is dead space
areas which are ventilated but don’t participate in gas exchange
