Ventilation in mammals Flashcards
what is the process of inspiration( breathing in)
- external intercostal muscles and diaphragm muscles contract
- causing the ribcage to move upwards and outwards, and the diaphragm to flatten increasing the volume of the thorax
- As the volume of thorax increases pressure inside the lungs decreases
- causing air to flow in the lungs
inspiration is an active process as it requires energy
what is the process of expiration ( breathing out)
- external intercostal muscles and diaphragm muscles relax
- ribcage moves downwards and inwards and the diaphragm becomes curved again
- As volume of thorax decreases lung pressure increases
- air is forced out of the lungs
Expiration is a passive provess
what is forced expiration
EG when you blow out candles on your birthday cake
- during forced expiration the INTERNAL intercostal muscles contract, to pull the ribcage downwards and inwards
Tidal volume?
the volume of air in each breath
vital capacity?
MAXIMUM volume of air that can be breathed in or out
Breathing rate?
how many breaths are taken per minute
Oxygen consumption/ oxygen uptake?
rate at which organisms use up oxygen
3 reasons for residual air
1) trachea are held open by cartilage
2) alveoli held open by elastic fibres
3) ribs and lungs can not be completely flattened
what does soda lime do in a spirometer
absorbs CO2
does the total volume of gas in the oxygen chamber of a spirometer increase or decrease
decrease
This is because the air that is breathed out is a mixture of O2 and CO2
- CO2 is absorbed by soda lime
- so there is only oxygen left in the chamber wihich the person inhales from
- as this oxygen gets used up by respiration, the total volume decreases
how to work out oxygen consumption on a graph produced by a spirometer
draw a slope
basically draw a tangent
and work out the gradient
change in y divided by change in x
