mechanics of breathing Flashcards
what respiration occurs within a cell
internal respiration
what is the exchange and transport of gases around the body called
external respiration (ventilation)
where is the rythm of breathing generated
medulla
medullary centers
dorsal respiratory group - controls inspiration sending signals to the inspiration muscles ventral respiratory group -controls inspiration and expiration inactive during quiet repsiration
what is found in the pons
pneumotaxic centre increases rate, shortens inspiration inhibitory effect on inspiratory centre apneustic centre increases depth and prolongs inspirations stimulates inspiratory centres
what do the centres in the pons do
send stimuli to medulla
control rate and depth
chemoreceptors
central chemoreceptors medulla moinitors cerebrospinal fluid (CO2 and pH) peripheral chemoreceptors carotid sinus, aortic arch
quiet expirayion
elastic recoil of lung
relaxation of external IC and diaphragm
accessory muscles of forced expiration
abdominal muscles - push diaphragm up
internal IC -depress ribs
accessory muscles of forced inspiration
scalenes - upper ribs
sternocleodimastiod - sternum
pectorals - pulls ribs out
why does a cavity lead to lung collapse
forces are not balanced (inward and outward)
what is a measure of elasticity
complinance
ease of the lungs/thorax expanding
low compliance - harder to breath in
high compliance- harder to breath out
components of elastic recoil in the lungs
elastic tissue
mucus/surfactant creates surface tension
surface tension and alvelio
alveoli are different sizes
larger alveli = lower pressure
movement of air from smaller to larger, collapse of smaller alveli
surfactant overcome collapse
surfactant
lipids and protiens
produced byType II pneuocytes
lines airway surfaces
