ch 3 breathing Flashcards
small organisms with large sa:v are able to diffuse nutrients___
faster
larger organisms with smaller sa:v ratio have __ to increase ____
adaptations, exchange
what are the adaptations of exchanging surfaces
- large surface area
-thinly skinned which provides a shorter diffusion path
-efficient blood supply
-being ventilated
where are the lungs located and how are they protected and seperated
-thorax
-ribs
-diaphragm
how does the ventilation of the lungs start
by movements of your ribcage and diaphragm
what happens when you breathe in
your intercostal muscle contracts which pulls your ribs upwards and outwards, then the diaphragm flattens to increase the volume of the thorax
what happens to the pressure inside your throax when you breathe in
it drops because the ame gas is inside a much bigger space which causes more air to move into your lungs by atmospheric pressure
how do you breathe out
the intercostal muscle relaxes and your ribs drop down and inwards, diaghraph returned to its curved shape which causes the pressure of the thorax to increase and air to be forced our of your lungs
how are alveoli adapted
-rich supply of blood to maintain a concentration gradient
-cappilaries are one cell thick which allows diffusion to take place over a shorter distance
how does having a steep concentration gradient make breathing effective
due to lots of blood which comes into the lungs being low in oxygen and high in co2
how do mechanical ventilation systems work
-positive pressure and negative pressure
why are breathing aids needed
to help people who are paralysed or have a disease which cannot ventilate their lungs
how do negative pressure ventilators work
cause air to be drawn into the lungs which is then exhaled passively
how do possive pressure ventilators work
they force carefully measured air into patients lungs then air pressure automatically stops
whats the benefit of using positive pressure ventilators
they can be easily moved around unlike the negative pressure ventilators
-patents have more control over the ventilation
