gas exchange Flashcards
what is gas exchange?
the exchange of o2 and co2 in the alveoli
what are all features in gas exchange surfaces limited to?
- large surface area
- thin wall/membrane
- good blood supply
- good ventilation with air
what experiments are used to test for co2 levels in air?
- hydrogen carbonate
- limewater
what is the positive result to a hydrogen carbonate test?
pink/red to yellow
what is the negative result to a hydrogen carbonate test?
pink/red to purple
what is the positive result to a limewater test?
clear to milky
what is the negative result to a limewater test?
remains clear
what is the % of o2 in inspired air?
21%
what is the % of o2 in expired air?
16%
what is the % of co2 in inspired air?
0.04%
what is the % of co2 in expired air?
4%
what is the % of water vapor in inspired air?
0.2 - 4%
what is the % of water vapor in expired air?
5 - 7%
what is the % of nitrogen in both inspired and expired air?
78%
when is the composition of oxygen highest?
in inspired air
when is the composition of carbon dioxide highest?
in expired air
when is the composition of water vapor the highest?
in expired air
what is the order of the pathway of air?
nasal cavity → pharynx → trachea → bronchus → bronchioles → alveoli
when breathing in, the internal intercostal muscle ______, the external intercostal muscle and diaphragm ______, and the pressure in the alveoli _____
relaxes, contracts and decreases
when breathing out, the internal intercostal muscle ______, the external intercostal muscle and diaphragm ______, and the pressure in the alveoli _____
contracts, relaxes and increases
why is does the trachea have c-shaped rings?
to accomondate the oesophagus when peristalsis is taking place (the gaps/open part allow the lumps of food to pass through)
how does the breathing system protect itself from pathogens and bacteria?
- goblet cells: produces mucus
- mucus: sticky substance that traps pathogens
- ciliated cells: moves the mucus away from the part of the organ up into the mouth to be swallowed.
what are the effects of physical activity on breathing?
- increased frequency of breathing
- increased depth of breathing
why is there increased depth and frequency of breathing during physical activity?
bc the muscles are working harder and aerobically respire more bc they need more oxygen to be delivered to them.
(this is also to avoid the production of lactic acid, which can lower the pH of cells and denature enzymes)
