ventilation in mammals Flashcards
what happens during inspiration
diaphragm contracts and flattens
external intercostal muscles contract, moving ribcage up and out
thoracic volume increases
thoracic pressure decreases
air flows into lungs to equalise the pressure difference
what happens during passive expiration
diaphragm relaxes and curves up
external intercostal muscles relax, moving ribcage down and in
thoracic volume decreases
thoracic pressure increases
air flow out of lungs
what happens during active expiration
exhale forcibly using energy
internal intercostal muscles contract pulling ribcage down and in
abdominal muscles contract, moving the diaphragm up
thoracic volume decreases hard and fast
thoracic pressure increases rapidly
air flows out of the lungs
how can the lung capacity be measured
peak flow meter
vitalograph
spirometer
how does spirometer work
Static lower half of tank is full of water
Mobile upper half of tank is full of oxygen
Breathe out into the tank and the upper half will rise
Breathe in from the tank and the upper half will fall
Trace marker is attached to the mobile upper half
define vital capacity
maximum volume of air an individual can inhale and exhale during a deep breath
define tidal volume
air inhaled and exhaled when at rest
define residual volume
small volume of air remain in lungs when you have exhaled as hard as possible
define inspiratory reserve volume
the maximum volume of air you can breathe in over and above normal inhalation
define expiratory reserve volume
maximum volume of air you can force out of your lungs over and above the normal tidal volume of air you breathe out
graph
total lung capacity
sum of vital capacity and residual capacity
define breathing rate
number of breaths taken per minute
worked out from the graph by counting how breaths are taken per minute
ventilation rate
tidal volume x breathing rate per minute
