the mechanism of ventilation Flashcards
what is the importance of breathing
animals need to maintain a concentration gradient across their exchange surfaces so that oxygen will diffuse into the blood and carbon dioxide will diffuse out
how do fish maintain their concentration gradient
they keep a continuous stream of oxygenated water moving through their gills
how do mammals maintain their concentration gradient
in the alveoli by ventilation
what is ventilation
the refreshing of air in the lungs so that there is a higher oxygen concentration than in the blood and a lower carbon dioxide concentration
another word for ventilation is…
… breathing
how is air moved in and out of the lungs
as a result of pressure changes in the thorax brought about by breathing
what is the thorax
chest cavity
how is breathing facillitated
the ribs and diaphragm provide a cage in which pressure changes occur to facilitate breathing
what does ventilation replace used air with
fresh air and brings in more oxygen whilst also removing carbon dioxide
what does ventilation ensure
the concentration of oxygen in the air of the alveolus remains higher than in the blood
the concentration of carbon dioxide in the alveoli remains slower than in the blood.
what is another word for inspiration/inhalation
breathing in
is inhalation an active or passive process
active
describe the mechanism of inspiration
- diaphragm muscle contracts and moves down
- external intercostal muscles contract while internal intercostal muscles relax
- thoracic volume increases, thoracic pressure decreases
- airs flows into the lungs (to equalise the pressure difference
what is another word for expiration/exhalation
breathing out
is exhalation active or passive
passive
